AeroElectric-Archive.digest.vol-ef
March 31, 2005 - April 05, 2005
> environment for that appliance such that it's isolated from an
> effect it cannot tollerate.
>
>
>>I think Paul mentioned a load dump from switching off the landing
>>lights. Should I also shut off electronics before shutting off landing
>>lights? Would a rheostat be a better device than a toggle switch for
>>turning landing lights on and off?
>
> Here we have an excellent example of mis-use or misunderstanding
> of words. As long as there is a battery on line, there are NO
> perturbations of bus voltage due to operation of any accessory
> that should be of concern to the builder. A "load dump" in the
> contemporary sense is a perturbation of rare and exceedingly
> large magnitude that occurs when large load changes are made
> on a system that does not have the stabilizing benefits of a
> battery.
>
> I've often suggested that this event should be called a "battery
> dump"
> event. In the certified airplane world, a "load dump" is just
> what Paul described . . . a large reduction in system load. This
> happens any time we shut of a 150A Freon compressor, or 200A of
> electric tail de-ice. Yes, this produces a perturbation in bus
> voltage that we EXPECT and have LEARNED TO TOLERATE by observing
> the system behavior based on decades of performance.
Bob I refuse to change the words LOAD DUMP as its a WORLD WIDE TERM FOR THIS
EVENT. There are 300,000 hits if you use the right search engine on
alternator load dump. Its a widely discussed issue and perhaps strangle the
solution seems always to be a Transorb or similar acting device as a
reliable solution. I simply do not understand your objections.
150 amp or 200 amp. GET real Bob, in our world 20 amp hyd pump is big, and
with no battery 10 amps is a large load dump that will trip your OVP 100% of
the time. As I have seen and can get notarized statements from the pilot(s)
that open cell battery failure in flight has happened; it's real and its
time we stopped the 'head in the sand' attitude that its not a concern. Its
far far more likely to have a open battery than a runaway alternator based
on failures that are easy to document.
>>Your observation that the discussion of malfunction modes, however
> rare,
>>may get exaggerated attention from the more worry-prone among us is a
>>point well taken. I suspect I am one of those: "constructive worry" is
>>at the core of my professional life, and it can be difficult to leave
>>these essential traits at work. But in my defense, I am building a new
>>airplane, and I want it to be the best it can be--or at least, at the
>>intersection of technology and expense that I find most harmonious.
>
> 99% of the worries out there right now are unnecessary because
> they are founded on misconception and concerns not based on
> the physics and practical realities. This is why I've prefaced
> all current discussions with experiments that describe what parts
> are used and what behaviors they show when operated in a specific
> manner. This is hard data that drives good interpretation and
> invites anyone to repeat the experiment to either confirm the
> results or illuminate errors. This is not a matter persuasiveness
> but accuracy.
A sample of one test in no way proves much and is never used in aerospace
engineering to do more than demonstrate the concept works. It does not
suggest that other tests will have similar results as long as there is no
detailed worst case analyses to support the test results are also
applicable. You got 15 ms and the spec says it can be 800 ms. Basing the
time sequenced events or parts power dissipations on this one atypical test
is not real engineering in any form I know or respect.
>
>
>>Incidentally, I should mention that I will take your advice and install
>>two P-mags instead of one P-mag and one E-mag. $250 for another level
> of
>>single-point redundancy. But for starting and idling, the engine IS
>>still dependent on the electrical system. P-mag's self-power output is
>>linearly proportional to rpm and doesn't become completely independent
>>of bus power until about 1600-1800 rpm.
>
> That isn't a big down side. How often do you drop below 1800 rpm
> before you begin descent to landing? Even if the power lead to an
> p-mag was compromised such that one ignition drops off line in a
> low power descent, you would have to have both power supplies
> open before it becomes an issue for comfortable completion of
> flight and the failure will be caught at the next pre-flight.
>
> Better yet, write a procedure into your shutdown check list to
> drop battery power off on one e/p-mag at a time to see that they
> run at ramp idle.
>
> With respect to your opening concerns, the vast majority of
> accessories
> you have to choose from are not adversely affected by perturbations
> of voltage on the bus for all normal operations. The only
> perturbations
> of significant concern would be failed regulators (persistent and
> extreme over voltage) or "load dump" transients brought on by
> large reduction of system loads without benefit of a battery. The
> first is easily mitigated by an OV protection system teamed with
> the
> bus stabilizing effects of a well-maintained battery. The latter
> is not a big concern because the potential for such an event
> arises only when a battery contactor has gone open.
>
> That prompts an interesting thought . . . suppose we put a fat
> diode
> across the battery contactor so that the cathode is tied to the
> battery
> side, anode to the bus side. This diode would not interfere with
> normal
> operations of the battery contactor . . . but should the contactor
> open because of solenoid failure -or- wiring failure, the bus would
> still benefit from the stabilizing effects of the battery for
> clamping
> of positive going transients under the "load dump" scenario. I'll
> have to noodle over that one for a bit to see if there's any
> downside.
> A diode/battery combination makes a hell-of-a-transorb capable of
> holding
> the bus at or below 18 volts for quite some time. Certainly for the
>
> duration
> of a load dump perturbation.
>
> Bob . . .
>
>
________________________________________________________________________________
| From: | "John Swartout" <jgswartout(at)earthlink.net> |
| Subject: | Making real world sense of the OVP thread |
Paul, how do you charge your back-up battery independent of the main
bus?
________________________________________________________________________________
| From: | B Tomm <fvalarm(at)rapidnet.net> |
| Subject: | Making real world sense of the OVP thread |
Paul,
Excellent post! I like and agree with the idea of ommiting the OVP system
that ala Bob's design. Myquestion is how to effectively connect all those
transorbs? I don't know what they look like but assume they are a device
with two wire leads coming out. Anyway I would like to know how to add
them to my electrical system which uses fuse blocks ala B&C for the busses.
Bevan
RV7A
more knowledgable thanks to the likes of Bob, Paul and many others on this
and other lists. Thank you.
-----Original Message-----
From: Paul Messinger [SMTP:paulm(at)olypen.com]
Subject: Re: AeroElectric-List: Making real world sense of the OVP thread
----- Original Message -----
From: "John Swartout" <jgswartout(at)earthlink.net>
Subject: AeroElectric-List: Making real world sense of the OVP thread
>
>
> Bob, Paul, Eric, et al:
>
Well John,
Here is how I think we stand. (Yes I am somewhat upset at recent posts on
this subject suggesting there is nothing wrong with status quo).
There are far more issues STILL to be resolved that we started with. We
started with issues about the current designs and so far I have seen no
solutions to any of the issues brought up.
I have seen many questions asked and +/- 50% are never answered. Perhaps
pocket vetoed as given time things seem to simply fade away.
I initiated this issue (OVP etc) with the results of a sub part of the load
dump testing from last year.
First a load dump is a normal event as far as the alternator is concerned.
We depend on the battery to act as a huge current sink to stabilize things.
ALL current Aeroelectric designs (as far as I can tell) prevent the
emergency mode of "no battery operation" as the OVP (as a standalone
module) or internal to the LR-3 are fast acting and cannot tell the
difference from a 5+ amp load dump and a hard alternator regulator failure
in the case of no battery operation. Why discard this mode of emergency
operation?? We have seen multiple batteries and alternators suggested. In
all cases the alternator only mode of operation is not only ignored, the
parts suggested as required on the alternator to protect for failures so
rare as near impossible to hear of (compared to engine mechanical failures
several times per week or so it seems) actually preclude this otherwise
simple mode of emergency operation. Of course if we define the battery as
never failing (open in this case) it might then make sense. As I have
documented 3 local "fail open" of aircraft certified batteries in the past
3
years it seems that to assume that batteries never fail open is at best
foolish to suggest.
How many failures do we need to protect for. Lets see it must be at least
three as dual batteries and dual alternators seems a good idea :-). Two
batteries, either can fail, and dual alternators so either can recharge the
battery.
What's wrong with no single failure and this can be done with Dual mags and
carb, or one battery and one alternator IF the alternator can run the
system
with a failed battery. Been flying with dual mags for 80 years and now we
need more backups for a much more reliable electrical system???
So If you want to have the ability to operate with no battery or operate in
the case of the battery having an open cell (far more likely than an
alternator regulator failure) you must not have either of the above devices
in your aircraft as they are very likely (near 100%) to false trip the
alternator off line. Their design simply does not address the normal load
dump case with no or a failed battery.
A failed alternator and failing high is very different, and here the LR-3
and OVP module act swiftly to short the system bus and open the associated
CB. This process produces huge currents that overload the CB and a single
case results in potential damage to meet specs of the CB. Thus every time
there is an OVP CB trip its necessary to replace the CB per local FAA
verbal
comments. Certificated aircraft only to be sure but who wants to rely on a
CB that may not trip properly next time? There is no need for large
currents
but the present designs create them (the only debate is what I found and
what Bob found as both were far higher than the max 'no damage' current).
So far a proper resistor to reduce the currents has not been defined that
is
not operated out of its specified currents. Special designed resistors are
required designed for hi current surges as compared with their wattage
rating which is not the design driver here.
There has never been a worst case design analysis to prove the present
designs will safely work under all parts types and specifications. This is
a
standard engineering design practice and requirement of any design to be
built more than once.
I could go on but I see no point. We are subjected to strange logic and
sample tests of one to support a poor design concept and implementation. I
have never seen the application of a crowbar in this type of design nor
have
any of my associates. Gross misapplication of the crowbar approach in every
opinion I got.
The facts as reported to Van's are clear. Van's says 100% of alternators
reported failed last year had some type of OVP protection added and the
failure occurred simultaneous with the OVP tripping. Perhaps it was a valid
trip but that logic is hard to support given that the thousands of no
failures with NO OVP added in. Vans has told me it would seem the adding of
the OVP devices is causing the failures and Vans does not have them on the
factory acft and does not recommend them to builders.
I have asked around the auto repair shops and auto parts stores locally and
NONE had ever had a alternator failure where the failure was a HI voltage
output.
Are we worrying about a failure so rare (and given that I feel the fix is a
poor design) that the fix is causing problems that are not there to begin
with? That its been the "standard for 40 years" and FAA certified is no
proof of quality or good design. The FAA routinely certifies bad designs of
every sort all the time.
I years ago took a different approach. On the load side of every CB I have
a
transorb sized so if the alternator runaway with HI voltage the transorb
will clamp the HI voltage and opens that specific CB and thus protect
expensive and or critical equipment. As I have a fully electrically
dependent aircraft I have a backup battery system for the engine that is
independent of the main bus so a fault hi or low on the main bus will not
affect the backup system.
Given the many CB's and associated transorbs there is essentially a OVP
distributed network in the acft wiring. under $10 for the transorbs and
simple to put across the CB. Would work with fuses as well.
Not the only related post planned but this one is already too long and has
too many subjects
Paul
________________________________________________________________________________
| From: | B Tomm <fvalarm(at)rapidnet.net> |
| Subject: | dual aft mounted batteries |
Paul and Bob
I would like your opinion/advice on the following scenario. Based on Bob's
Z19 less OVP.
Facts:
RV7A with Subaru based engine
Single alternator and dual aft mounted batteries
Two aft mounted contactors and battery buss blocks
Two forward mounted main electrical busses fed by large cable runs between
aft battery location and firewall.
Here are my questions:
A) Is it advisable to have the output of each battery contactor commoned
together right at the output lug of the contactors and then run forward to
the main buss block and ground point on single large conductors such as 4
or 6AWG? (as opposed to separate wires as some drawings show it).
B) This leaves a single cable as the sole provider of power for the starter
and main buss (lighting circuits). I don't think this cable is likely
gonna fail in flight causing an emergency but maybe I have overlooked
something such as practical connectors. Perhaps there is not an acceptable
way to connect multiple large wires to the battery contactors? I don't
have them yet so I can't see how big they are.
C) What is your experience or opinion with Periheliondesign.com solid
state battery contactors? I would like to use these SS devices in place of
standard contactors because their current requirements are far less than
the coil of a traditional contactor, they are lighter and should last
forever.
Your comments are appreciated.
Bevan
RV7A
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> thread |
| Subject: | Making real world sense of the OVP |
thread
thread
>
>
>Bob,
> >What electronics?
> Dynon D-10A EFIS
> Grand Rapids Technologies Model 4000 EIS
> ICOM A200 Comm Radio
> KT76A Transponder
> AmeriKing AK-350 encoder
> PS Engineering PM1000II Intercom
> Dell Axim x50 PDA with some kind of power supply
> Teletype GPS receiver
>
>I'd never heard of DO-160 Recommendations until you mentioned them on
>this list, and I've never seen any reference to them in the
>documentation for the devices I have. I have all of these devices except
>the Dynon, the Dell, and the GPS, but they don't yet have an electrical
>system to call home--so they won't be tested by me until I have build
>the electrical system and fire it up. I am ready to do that right
>now--that's why I'm asking so many questions. I want to give them a
>good, safe home.
If it's commercial, off the shelf stuff . . . or products intended
for the OBAM aircraft community, then you probably won't hear or
see anything about DO-160 . . .
>Concerning a fat diode across the battery contactor:
>
>Diodes, if memory serves, allow electricity to pass through them in only
>one direction. Is it true that when you open the battery contactor with
>a lot of electricity passing through it, the electricity jumps the gap
>while it still can, and this is a violent event like a capacitor
>discharging or a spark plug firing? And we know in which direction the
>spark leaps? And does a momentary reversal of polarity occur? So a
>diode could arrest that spike if we know which way the spike wants to
>go? How would it do that? Would it convert the electricity to heat? Is
>a diode a good heat sink?
This isn't about contact arcing. Any time you break a pair of
contacts carrying any amount of current there WILL be arcing.
The magnitude of the event is dependent on nature of the load,
voltage in the system and how much current is flowing at the time
the contacts break.
The ONLY time I'd be real concerned about this phenomenon is
when a plain vanilla contactor is trying to unhook the b-lead
of a runaway alternator. Starter contactors take the biggest
hits and they are specially constructed to have high closing
forces and rapid opening velocities. The battery contactor
closes with very light loads and opens with very light loads
and most battery contactors can be expected to operate for
thousands of cycles trouble free. There is no violence of
fire and brimstone under normal operating conditions for
battery contactors. I might point out that the S701-1 contactor
is RATED to switch only 70 amps. By waiting until the contactor
is closed and stable before you hit it with starter current, it
will CARRY the 200+ amps for cranking very nicely.
The load-dump transient that can be easily generated when
there is no battery on the bus is always positive going.
Your perception of diode operation is correct. We'd put the
diode across the battery contactor so that should the contactor
NOT be closed while the system is powered up, any positive
going load dump transients would be loaded no only by the
system but by the battery through the diode. So we'd get
the benefits of battery filtering of positive transients
whether the contactor is closed or not.
This isn't about arcing or even about handling a ton of
energy. It's figuring out what to do with a handful of
watt-seconds of energy during any load dump event.
Bob . . .
________________________________________________________________________________
| From: | Ken <klehman(at)albedo.net> |
| Subject: | Re: Making real world sense of the OVP thread |
This has been alluded to a couple of times but is a melted field winding
really very probable in this situation? I would have guessed that the
solid state device that switches the field current would open circuit
from current/voltage/heat before the windings actually "fried" and
started shedding metal.
Ken
> Had the OVP system operated due to a real OV event, then
> the regulator (root cause of the OV event) is already
> toast so the event that occurs after the b-lead contactor
> opens isn't event a load-dump transient . . . unless you
> want to consider a climb past 100 volts that continues
> until the field windings fry as a "transient".
>
>
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> thread |
| Subject: | Re: Making real world sense of the OVP |
thread
thread
>
>Well John,
>
>Here is how I think we stand. (Yes I am somewhat upset at recent posts on
>this subject suggesting there is nothing wrong with status quo).
>
>There are far more issues STILL to be resolved that we started with. We
>started with issues about the current designs and so far I have seen no
>solutions to any of the issues brought up.
I'm sorry. Which issues? I thought that a battery's demonstrated
abilities to supply high levels of current while maintaining
minimum bus voltage -AND- a demonstrated ability to stand off the
full output of a runaway alternator until the OV protection system
can act were answers to a number of concerns.
>I have seen many questions asked and +/- 50% are never answered. Perhaps
>pocket vetoed as given time things seem to simply fade away.
Paul, you know better than that. Nobody has veto power here
and I've never avoided a question. Please pose any question
you like and I will do my best.
>I initiated this issue (OVP etc) with the results of a sub part of the load
>dump testing from last year.
>
>First a load dump is a normal event as far as the alternator is concerned.
>We depend on the battery to act as a huge current sink to stabilize things.
agreed
> ALL current Aeroelectric designs (as far as I can tell) prevent the
>emergency mode of "no battery operation" as the OVP (as a standalone
>module) or internal to the LR-3 are fast acting and cannot tell the
>difference from a 5+ amp load dump and a hard alternator regulator failure
>in the case of no battery operation.
absolutely . . . but the question of no-battery operation has
never been addressed nor recommended in any of my writings. If
you're proposing this as a useful mode and are prepared to make
the environment suit the appliances, that's certainly okay by
me . . . but how does this affect the usage of components that
I've suggested or recommended in the context of a battery being
present? If you're concerned about the "status quo" having
no admitted problems, please recall that the first test I did
in the white paper published a few weeks ago started with a
investigation/demonstration of BATTERY performance. That test
is the foundation of the "status quo" for which I have yet
to identify any problems. If you wish to removed the battery
from discussions, that's fine . . . but we're no longer talking
about any system recommended in the 'Connection and therefore
not representative of any "status quo".
> Why discard this mode of emergency
>operation?? We have seen multiple batteries and alternators suggested. In
>all cases the alternator only mode of operation is not only ignored, the
>parts suggested as required on the alternator to protect for failures so
>rare as near impossible to hear of (compared to engine mechanical failures
>several times per week or so it seems) actually preclude this otherwise
>simple mode of emergency operation. Of course if we define the battery as
>never failing (open in this case) it might then make sense. As I have
>documented 3 local "fail open" of aircraft certified batteries in the past 3
>years it seems that to assume that batteries never fail open is at best
>foolish to suggest.
Okay, in this case, there's nothing published in the 'Connection
that applies and we're discussing the fabrication of a new
environment. A laudable goal . . . but not easy. Let's get to
it and see if it can be done.
>How many failures do we need to protect for. Lets see it must be at least
>three as dual batteries and dual alternators seems a good idea :-). Two
>batteries, either can fail, and dual alternators so either can recharge the
>battery.
Whoa! There are a half dozen architectures proposed in the z-figures
which address various levels of criticality based on intended usage
of the airplane and how it's fitted. You've thrown the whole pile of
options into one bucket. If I were building an airplane today it would
be fitted with two p-mags and a Z-13 system with one battery and
not quite a dual alternator system. I'd be perfectly content to
fly this in everything except IFR where there is a potential for
ice or convective conditions. There is NO amount of electrical
system reliability that will offset those hazards.
>What's wrong with no single failure and this can be done with Dual mags and
>carb, or one battery and one alternator IF the alternator can run the system
>with a failed battery. Been flying with dual mags for 80 years and now we
>need more backups for a much more reliable electrical system???
Lost you again. Once you've opted for all electric then there's
a drive pad open that you can either cover up or fill with
something relatively cheap, light and much more useful in the
all electric environment than the cover plate. I'm not suggesting
that the SD-8 is any kind of requirement . . . just an attractive
option that I would certainly incorporate if it were my choice.
If you can put a one battery/one alternator system together
with the intention of supporting alternator only operations
and have a system that is no worse than we work with today,
it would be a fine achievement. But the alternator only operation
opens whole new avenues of investigation that until now,
I've chosen not to address in light airplanes.
I can't argue with your "open battery" experiences but in my
own experience, this is a very rare event . . . much more rare
than loss of a certified alternator. Given the service history
of the current B&C offerings, perhaps this is a good time
to consider crafting a system that will run well without a
battery.
>So If you want to have the ability to operate with no battery or operate in
>the case of the battery having an open cell (far more likely than an
>alternator regulator failure) you must not have either of the above devices
>in your aircraft as they are very likely (near 100%) to false trip the
>alternator off line. Their design simply does not address the normal load
>dump case with no or a failed battery.
>
> A failed alternator and failing high is very different, and here the LR-3
>and OVP module act swiftly to short the system bus and open the associated
>CB.
If there were no battery on line, it's likely that a crowbar
OV trip will stall the alternator and accomplish system shutdown
WITHOUT popping the breaker. It's an established and acknowledged
fact that the crowbar ov protection system DEPENDS on a battery
being present to achieve the designed operating criteria.
>This process produces huge currents that overload the CB and a single
>case results in potential damage to meet specs of the CB. Thus every time
>there is an OVP CB trip its necessary to replace the CB per local FAA verbal
>comments. Certificated aircraft only to be sure but who wants to rely on a
>CB that may not trip properly next time? There is no need for large currents
>but the present designs create them (the only debate is what I found and
>what Bob found as both were far higher than the max 'no damage' current).
I'm not finding anything in the industry to support this. I've
searched our maintenance policies and asked our ol' gray beard
DERs about this and there's no acknowledgement of any requirements
along this line. I have turned up a number of anecdotal "requirements"
that adopted a similar philosophy but of course, they can never cite
a repeatable experiment. My circuit breaker guru buddy is out of town
but we've agreed to talk next week and he's going to search Eaton/Cutler-
Hammer's engineering and marketing documents for information on
this matter.
For my own part, I've personally conducted hundreds of "beyond the
spec'd curves" crowbar operating events on a single (admittedly
mil-spec) breaker. I'm not ready to address this issue in detail
but it IS being researched and I'll be pleased to speak to it
with after I've been educated in the matter. It will take several
weeks.
>So far a proper resistor to reduce the currents has not been defined that is
>not operated out of its specified currents. Special designed resistors are
>required designed for hi current surges as compared with their wattage
>rating which is not the design driver here.
>
>There has never been a worst case design analysis to prove the present
>designs will safely work under all parts types and specifications. This is a
>standard engineering design practice and requirement of any design to be
>built more than once.
I'm not sure that what you've perceived is a hard-limit in the
specifications having any more influence than reduced breaker life.
But when we're dealing with breakers spec'd for thousands of
operations inside the published curve limits, I'm not sure I'm
concerned about degrading breaker life to a few hundred operations.
Admittedly, my experience is undocumented. I may craft a test to
document but I'll wait until my friends in the industry share their
findings.
>I could go on but I see no point. We are subjected to strange logic and
>sample tests of one to support a poor design concept and implementation. I
>have never seen the application of a crowbar in this type of design nor have
>any of my associates. Gross misapplication of the crowbar approach in every
>opinion I got.
Never claimed this was any kind of industry standard other than
for computers. The experience of you and your associates does not
provide definitive data under which the design can be labeled either
strange or poor.
>The facts as reported to Van's are clear. Van's says 100% of alternators
>reported failed last year had some type of OVP protection added and the
>failure occurred simultaneous with the OVP tripping. Perhaps it was a valid
>trip but that logic is hard to support given that the thousands of no
>failures with NO OVP added in. Vans has told me it would seem the adding of
>the OVP devices is causing the failures and Vans does not have them on the
>factory acft and does not recommend them to builders.
Which is entirely his privilege . . . but he still cannot articulate
root cause for the conditions he has observed. He has his customers
to service and I have mine.
>I have asked around the auto repair shops and auto parts stores locally and
>NONE had ever had a alternator failure where the failure was a HI voltage
>output.
That's very reassuring to hear. Are you ready to install an internally
regulated machine in your airplane without benefit of OV protection?
I note that you're advocating transorbs at each breaker below . . . why?
>Are we worrying about a failure so rare (and given that I feel the fix is a
>poor design) that the fix is causing problems that are not there to begin
>with? That its been the "standard for 40 years" and FAA certified is no
>proof of quality or good design. The FAA routinely certifies bad designs of
>every sort all the time.
So? I've never hung my hat on certification as a figure of merit.
Virtually ALL of my work at RAC involves chasing rats out of
certified designs. Just finished one today that's only a year old and
tomorrow I start on one that's over 30 years old.
>I years ago took a different approach. On the load side of every CB I have a
>transorb sized so if the alternator runaway with HI voltage the transorb
>will clamp the HI voltage and opens that specific CB and thus protect
>expensive and or critical equipment.
Lost you here. Are you suggesting that a transorb per circuit
breaker can be depended on to protect the equipment . . . if you
do get an ov event, you end up with a whole panel full of blown
fuses/breakers and the equipment is all okay but none of it is working?
>As I have an fully electrically
>dependent aircraft I have a backup battery system for the engine that is
>independent of the main bus so a fault hi or low on the main bus will not
>affect the backup system.
Okay, you've already got a two battery system. Figure Z-11 with
the added second battery is essentially free of the effects
of any one battery or battery contactor going open. Figure Z-19
is a similar example. Once you have a two-battery system, why
be concerned with open battery failures or alternator only
operations? That takes a dual failure.
>Given the many CB's and associated transorbs there is essentially a OVP
>distributed network in the acft wiring. under $10 for the transorbs and
>simple to put across the CB. Would work with fuses as well.
Okay, let's assume the rare but dreaded ov event has occurred
and fuses/breakers are starting to pop. How is the pilot going
to be notified? What are his expected duties for bringing the
system under control? What are the potential problems he'll
be faced with for continued, comfortable flight? Are we considering
a battery to be present or absent during the ov event?
>Not the only related post planned but this one is already too long and has
>too many subjects
Agreed. Peel it back one layer at a time. Give me a question that
you believe I have ignored or "vetoed" along with any test
you'd like me to perform to deduce the answer. May I suggest:
Give me an array of circuit breakers by size and the suggested
transorbs to install downstream. I'll take it out to RAC, put
my data acquisition system on it and give it the acid test with
power supplies large enough to emulate the 60A alternator.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> thread |
| Subject: | Re: Making real world sense of the OVP |
thread
thread
>
>Some of your listed equipment have specific specs that are inside DO-160
>(tighter that is).
>
>I have reviewed DO-160 and its mostly toothless. Its full of suggestions and
>requirements things work after this test as you define it to work. Or even
>more strange requirements that the manufacturers set so in these cases
>DO-160 simply applies what ever the manufacturer says.
Gee . . . I and my associates have been reading and applying features
outlined in DO-160 for over 40 years and you're suggesting that it was
all for naught?
>There are NO requirements to do any of its parts and no requirements in the
>industry that I can find that require meeting any part of DO-160. No
>requirement to test, just to design to etc.
>
>Nice guidelines but I have my own list of equipment and NONE has been tested
>or even inspected by design to meet DO-160 as the mfgrs simple ignore this
>document.
No manufacturers I know can or will ignore this document because DO-160
is a levied requirement in EVERY specification we product and cited in
every TSO for electrical equipment that the FAA has issued. Yes, the
document
offers a wide range of testing tailored to the usage of the customer
but before certification is issued, you WILL have conducted and documented
testing per DO-160 and so identify that fact on the outside of the product.
>Perhaps its a valid and compliant document in the corporate and hi end
>avionics world.
If it goes into a TC aircraft it will be DO-160 qualified. Hi end, low end
and all ends.
>A reasonable design with a few properly placed transorbs will keep the 14V
>power system clean, at least to the extent required to meet OUR lists of
>equipment.
> > I'd never heard of DO-160 Recommendations until you mentioned them on
> > this list, and I've never seen any reference to them in the
> > documentation for the devices I have. I have all of these devices except
> > the Dynon, the Dell, and the GPS, but they don't yet have an electrical
> > system to call home--so they won't be tested by me until I have build
> > the electrical system and fire it up. I am ready to do that right
> > now--that's why I'm asking so many questions. I want to give them a
> > good, safe home.
> >
> > Concerning a fat diode across the battery contactor:
> >
> > Diodes, if memory serves, allow electricity to pass through them in only
> > one direction. Is it true that when you open the battery contactor with
> > a lot of electricity passing through it, the electricity jumps the gap
> > while it still can, and this is a violent event like a capacitor
> > discharging or a spark plug firing? And we know in which direction the
> > spark leaps? And does a momentary reversal of polarity occur? So a
> > diode could arrest that spike if we know which way the spike wants to
> > go? How would it do that? Would it convert the electricity to heat? Is
> > a diode a good heat sink?
>
>
>I must assume Bob is thinking about his position that batteries never fail.
>Nice concept but simply not true so the diode here is of no use in 100% of
>the cases. A simple low cost transorb works 100% of the time
>
>Bob I refuse to change the words LOAD DUMP as its a WORLD WIDE TERM FOR THIS
>EVENT. There are 300,000 hits if you use the right search engine on
>alternator load dump. Its a widely discussed issue and perhaps strangle the
>solution seems always to be a Transorb or similar acting device as a
>reliable solution. I simply do not understand your objections.
Not objecting . . . just making sure that we're all visualizing the
same thing. I take the same precaution when talking about current flow . . .
some folk were taught with "holes" others with "electrons". We can
call it by any name you wish as long as we're visualizing the same
thing. In the aircraft industry, load dump is measured both with
batteries on line and off line. Each condition calls for different
levels of testing under DO-160.
>150 amp or 200 amp. GET real Bob, in our world 20 amp hyd pump is big, and
>with no battery 10 amps is a large load dump that will trip your OVP 100% of
>the time. As I have seen and can get notarized statements from the pilot(s)
>that open cell battery failure in flight has happened; it's real and its
>time we stopped the 'head in the sand' attitude that its not a concern. Its
>far far more likely to have a open battery than a runaway alternator based
>on failures that are easy to document.
I admitted and acknowledged that having a battery present at all
times is key to the functionality of the systems described. If you
want to operated single battery and alternator only, then that's
a completely different world. Don't mind working toward goals in
that environment but let's be specific about environments.
> >
> > 99% of the worries out there right now are unnecessary because
> > they are founded on misconception and concerns not based on
> > the physics and practical realities. This is why I've prefaced
> > all current discussions with experiments that describe what parts
> > are used and what behaviors they show when operated in a specific
> > manner. This is hard data that drives good interpretation and
> > invites anyone to repeat the experiment to either confirm the
> > results or illuminate errors. This is not a matter persuasiveness
> > but accuracy.
>
>A sample of one test in no way proves much and is never used in aerospace
>engineering to do more than demonstrate the concept works. It does not
>suggest that other tests will have similar results as long as there is no
>detailed worst case analyses to support the test results are also
>applicable. You got 15 ms and the spec says it can be 800 ms.
Not at 150+ amps. I WAS operating out the top of the published
curve to get the performance demonstrated. What remains to be
discovered is whether operating in that mode is catastrophic or
simply accelerates wear rates.
> Basing the
>time sequenced events or parts power dissipations on this one atypical test
>is not real engineering in any form I know or respect.
I'm sorry but I'm not trolling for your respect. If you believe the
test is invalid because it's atypical, then it should be easy to
do the experiment again and demonstrate that it is NOT repeatable.
I'll do the test again next week with a cold soaked breaker.
You've chosen an interpretation of a data sheet which I don't read
that way and I'm digging into it to find out. I suspect that
we'll find that out of range operation of the breakers is not
an issue of hazardous failure to operate but a simple reduction in
life . . . in which case, the tests and anecdotal observations
I've offered are supported. We'll see.
Bob . . .
________________________________________________________________________________
| From: | "Larry Bowen" <Larry(at)BowenAero.com> |
| Subject: | Two impulse mags? |
I should clarify my original post.
I'm not having the best luck with my ElectroAir EI installation.
Reliability of MY installation in MY airplane has been less than expected.
I'm not bad-mouthing ElectroAir or Jeff Rose, who has provided great
customer service, I'm just looking for help and alternatives. Follow the
link to my web site below for details if interested.
-
Larry Bowen
Larry(at)BowenAero.com
http://BowenAero.com
> > > ----- Original Message -----
> > > From: "Larry Bowen" <Larry(at)BowenAero.com>
> > > To:
> > > Subject: AeroElectric-List: Two impulse mags?
> > >
> > >
> > >>
> > >>
> > >> I'm considering replacing my unreliable Rose elec ign
> with another
> > >> slick mag. Is there any crime in having two impulse mags so I
> > >> don't have to rely on the operator to keep the
> non-impulse mag off
> > >> while cranking? Or is there a better way?
> > >>
> > >> Starter and both ignitions are each on toggle switches.
> > >>
> > >> Thanks,
> > >>
> > >> -
> > >> Larry Bowen, RV-8/O-360
> > >> Larry(at)BowenAero.com
> > >> http://BowenAero.com
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> thread |
| Subject: | Re: Making real world sense of the OVP |
thread
thread
> Had the OVP system operated due to a real OV event, then
> the regulator (root cause of the OV event) is already
> toast so the event that occurs after the b-lead contactor
> opens isn't event a load-dump transient . . . unless you
> want to consider a climb past 100 volts that continues
> until the field windings fry as a "transient".
>
>
>
>This has been alluded to a couple of times but is a melted field winding
>really very probable in this situation? I would have guessed that the
>solid state device that switches the field current would open circuit
>from current/voltage/heat before the windings actually "fried" and
>started shedding metal.
>Ken
I don't see what would prevent it. IF we assume that an
alternator is capable of running self-excited to supply
energy to a system whether or not there is a battery present,
then it follows that it will also continue to supply its
own field excitation AFTER being disconnected from the
rest of the system due to an OV event. Further, the
same OV event will continue unabated within the alternator
making its self-destruction a certainty.
Bob . . .
________________________________________________________________________________
| From: | owner-aeroelectric-list-server(at)matronics.com |
Listers - PMags appear to be a good way to go safety wise as it renders (in
principle) ignition independent of the electrical system. But this only
happens if RPM is high enough.
In case of the unlikely scenario that the electrical system should die and
the RPM should fall below PMag's self sustaining level, would wind milling
by diving bring the engine RPM up sufficiently, thereby restoring engine
power?
A similar scenario would occur as one is on short final with engine at 800
RPM. If the electrical system is down, are we in a situation whereby the
PMag could stop generating its own electricity, thereby committing the
flight to a definitive landing no matter what, i.e. no go around
possibility?
Michle
RV8 - Wings
________________________________________________________________________________
| From: | "DonVS" <dsvs(at)comcast.net> |
The documents that were included with my P-Mags state that the units
continue to operate without batty support down to 700 rpm. Not making full
power but enough to sustain the engine. Don
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com]
Subject: AeroElectric-List: PMags and RPM
Listers - PMags appear to be a good way to go safety wise as it renders (in
principle) ignition independent of the electrical system. But this only
happens if RPM is high enough.
In case of the unlikely scenario that the electrical system should die and
the RPM should fall below PMag's self sustaining level, would wind milling
by diving bring the engine RPM up sufficiently, thereby restoring engine
power?
A similar scenario would occur as one is on short final with engine at 800
RPM. If the electrical system is down, are we in a situation whereby the
PMag could stop generating its own electricity, thereby committing the
flight to a definitive landing no matter what, i.e. no go around
possibility?
Michle
RV8 - Wings
________________________________________________________________________________
| From: | Jan de Jong <jan.de.jong(at)xs4all.nl> |
| Subject: | normally-on switch? |
If one needs a normally-closed-open-to-test switch is a cb the best
choice? Alternatives?
Properties looked for:
- reliable conductor of a wide range of currents
- normally-on appearance
- impossible to accidentally open
Thank you for opinions.
Jan de Jong
________________________________________________________________________________
| From: | "Jim Jewell" <jjewell(at)telus.net> |
| Subject: | Re: PMags and RPM |
I think this sounds like a good question to ask the people that make the
PMmags.
Does someone that plays a principle role in the company monitor the list?
Jim in Kelowna
----- Original Message -----
From: <owner-aeroelectric-list-server(at)matronics.com>
Subject: AeroElectric-List: PMags and RPM
>
> Listers - PMags appear to be a good way to go safety wise as it renders
> (in
> principle) ignition independent of the electrical system. But this only
> happens if RPM is high enough.
>
> In case of the unlikely scenario that the electrical system should die and
> the RPM should fall below PMag's self sustaining level, would wind milling
> by diving bring the engine RPM up sufficiently, thereby restoring engine
> power?
>
> A similar scenario would occur as one is on short final with engine at 800
> RPM. If the electrical system is down, are we in a situation whereby the
> PMag could stop generating its own electricity, thereby committing the
> flight to a definitive landing no matter what, i.e. no go around
> possibility?
>
> Michle
> RV8 - Wings
>
>
>
________________________________________________________________________________
| From: | Andrew Rowley <arowley(at)ncable.net.au> |
| Subject: | Re: Making real world sense of the OVP thread |
Robert L. Nuckolls, III wrote:
> The only component at-risk when internally regulated alternators
> are wired per Z-24 is the alternator itself. To date, ALL incidents
> of damage to the alternator using Z-24 architecture have been
> operator induced. I.e., the alternator was turned OFF while
> carrying a significant load.
>
> An internally regulated alternator with a b-lead contactor
> is at risk for this form of damage irrespective of the form
> of OV protection. In this case, the transient that damaged
> the alternator was a function of manipulation of controls
> . . . the OV protection system was not a participant.
This is one thing that concerns me. Before I read this list I was not
aware that the alternator could be damaged by turning it off. It seems
to me that eliminating this possibility should be an major goal in
designing these systems.
Switching a switch off should turn off any items dependent on the
switch. Switching it on should turn them on. Anything else (especially
damage) violates the principle of least astonishment.
--
Andrew Rowley
arowley(at)ncable.net.au
________________________________________________________________________________
| From: | "Alex Peterson" <alexpeterson(at)earthlink.net> |
> A similar scenario would occur as one is on short final with
> engine at 800 RPM. If the electrical system is down, are we
> in a situation whereby the PMag could stop generating its own
> electricity, thereby committing the flight to a definitive
> landing no matter what, i.e. no go around possibility?
>
> Michle
> RV8 - Wings
I don't know about fixed pitch props, but with a c/s, if your rpm was down
to 800, you would probably have already stalled due to low airspeed. Flight
idle at approach speeds is well above 800.
Alex Peterson
RV6-A 604 hours
Maple Grove, MN
http://www.home.earthlink.net/~alexpeterson/
________________________________________________________________________________
| From: | Andrew Rowley <arowley(at)ncable.net.au> |
| Subject: | Re: Making real world sense of the OVP thread |
Paul Messinger wrote:
> ALL current Aeroelectric designs (as far as I can tell) prevent the
> emergency mode of "no battery operation" as the OVP (as a standalone
> module) or internal to the LR-3 are fast acting and cannot tell the
> difference from a 5+ amp load dump and a hard alternator regulator failure
> in the case of no battery operation. Why discard this mode of emergency
> operation?? We have seen multiple batteries and alternators suggested. In
> all cases the alternator only mode of operation is not only ignored, the
> parts suggested as required on the alternator to protect for failures so
> rare as near impossible to hear of (compared to engine mechanical failures
> several times per week or so it seems) actually preclude this otherwise
> simple mode of emergency operation.
One problem I think is that in this environment the suggested systems
need to be generic enough that they will work on an aircraft without
knowing what else might be installed in the aircraft. The "worst case"
for a system designed to continue running alternator only might be, for
example, someone who had a circuit to flash their 2 x 100 watt landing
lights once a second, and continued to operate it for the rest of their
flight. They knew their alternator produced enough power, so why not?
The question then becomes what happens to the protection circuits in
this case? Do they continue operating, or do they give up the ghost too,
and what happens to the system then?
In some cases it is best to fail as early as possible, rather than try
to continue and set up a worse failure later.
> A failed alternator and failing high is very different, and here the LR-3
> and OVP module act swiftly to short the system bus and open the associated
> CB. This process produces huge currents that overload the CB and a single
> case results in potential damage to meet specs of the CB. Thus every time
> there is an OVP CB trip its necessary to replace the CB per local FAA verbal
> comments.
As commented earlier, I am skeptical that this is really a problem, as
it doesn't seem to be an issue with other CBs. The CB is designed to
trip with short circuit currents. You suggested that if a CB trips, you
could calculate the current and it was between you and the A&P whether
to replace the CB. I can't really imagine an A&P who would take
seriously a request to calculate the current to determine whether a CB
should be relaced after it trips - am I alone here?
> The facts as reported to Van's are clear. Van's says 100% of alternators
> reported failed last year had some type of OVP protection added and the
> failure occurred simultaneous with the OVP tripping. Perhaps it was a valid
> trip but that logic is hard to support given that the thousands of no
> failures with NO OVP added in. Vans has told me it would seem the adding of
> the OVP devices is causing the failures and Vans does not have them on the
> factory acft and does not recommend them to builders.
>
> I have asked around the auto repair shops and auto parts stores locally and
> NONE had ever had a alternator failure where the failure was a HI voltage
> output.
If we want anecdotal evidence, I was flying an aircraft recently
(Jabiru) and had a GPS plugged into the cigarette lighter socket. The
voltmeter on the GPS was reading about 16V. That seemed pretty high to
me, and convinced me that it is quite likely that many aircraft without
OVP fly around with high voltages undetected.
The only alternator failure I have had in a car also failed with high
voltage. (Confusing problem... the car would not start if you had just
been driving, but was fine 30 mins later once the battery recovered.)
Whether the repair shop would remember if asked I don't know.
Given the normal architecture, with a regulator sensing voltage and
adjusting the field current, I am not convinced that a high voltage
failure is much less likely than a low voltage failre.
--
Andrew Rowley
arowley(at)ncable.net.au
________________________________________________________________________________
| From: | "John Swartout" <jgswartout(at)earthlink.net> |
| Subject: | Making real world sense of the OVP thread |
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of
Andrew Rowley
Subject: Re: AeroElectric-List: Making real world sense of the OVP
thread
Robert L. Nuckolls, III wrote:
> The only component at-risk when internally regulated alternators
> are wired per Z-24 is the alternator itself. To date, ALL
incidents
> of damage to the alternator using Z-24 architecture have been
> operator induced. I.e., the alternator was turned OFF while
> carrying a significant load.
>
> An internally regulated alternator with a b-lead contactor
> is at risk for this form of damage irrespective of the form
> of OV protection. In this case, the transient that damaged
> the alternator was a function of manipulation of controls
> . . . the OV protection system was not a participant.
This is one thing that concerns me. Before I read this list I was not
aware that the alternator could be damaged by turning it off. It seems
to me that eliminating this possibility should be an major goal in
designing these systems.
Switching a switch off should turn off any items dependent on the
switch. Switching it on should turn them on. Anything else (especially
damage) violates the principle of least astonishment.
--
Andrew Rowley
arowley(at)ncable.net.au
I *think* this begins to explain why the experts favor externally
regulated alternators. I'm now re-thinking my plan to use the
internally-regulated alternator into which I've already invested nearly
$200.
John
________________________________________________________________________________
| From: | Charlie Kuss <chaztuna(at)adelphia.net> thread |
| Subject: | Re: Making real world sense of the OVP |
thread
> thread
>
>
> > Had the OVP system operated due to a real OV event, then
> > the regulator (root cause of the OV event) is already
> > toast so the event that occurs after the b-lead contactor
> > opens isn't event a load-dump transient . . . unless you
> > want to consider a climb past 100 volts that continues
> > until the field windings fry as a "transient".
> >
> >
> >
> >This has been alluded to a couple of times but is a melted field winding
> >really very probable in this situation? I would have guessed that the
> >solid state device that switches the field current would open circuit
> >from current/voltage/heat before the windings actually "fried" and
> >started shedding metal.
> >Ken
>
> I don't see what would prevent it. IF we assume that an
> alternator is capable of running self-excited to supply
> energy to a system whether or not there is a battery present,
> then it follows that it will also continue to supply its
> own field excitation AFTER being disconnected from the
> rest of the system due to an OV event. Further, the
> same OV event will continue unabated within the alternator
> making its self-destruction a certainty.
>
> Bob . . .
Bob, Paul & others,
I wish to thank all of you for your efforts on this subject. I've
learned quite a bit from your discussions. I now have a much better
appreciation for why both Bob & Paul prefer external voltage regulators.
For my own project, I've decided to follow the long time suggestions of
both Bob & Paul, to eliminate the internal voltage regulator from my 60 amp
ND alternator. For those listers who are unaware, Paul wrote a very nice
article in CONTACT magazine on how to accomplish this. I'll use his article
to perform "surgery" on my ND internal voltage regulator. This modification
effectively converts any internally regulated ND or Mitsubishi alternator
into an externally regulated unit.
I will still be following this thread for my own education.
Thanks
Charlie Kuss
________________________________________________________________________________
| From: | D Wysong <hdwysong(at)gmail.com> |
| Subject: | Re: normally-on switch? |
Would a regular toggle switch with a guard work for you?
D
________________________________________________________________________________
| From: | Richard Riley <Richard(at)RILEY.NET> |
| Subject: | OVP etc - do we have a bottom line? |
I've now spent much of the night trying to read and understand all the
objections to and defences of the crowbar OVP system.
I still have no idea who's right. I just have a migraine.
If I'm willing to spend enough money, can I build a system that satisfies
all the critics? For example, many of the crowbar posts involve internally
regulated alternators. If I'm using a B&C 60 amp alternator, an LR3, and
SD8 and 2 batteries, am I still in danger of frying $50k worth of avionics
because I blinked wrong?
Please understand, I am willing to spend whatever it takes to make this
problem (if it is a problem) go away. I don't want the "best" solution, I
want all the solutions that are worthwhile and applicable. I'm not going
to worry about an extra $100 for a transorb, I want belt and suspenders and
nail gun and epoxy. Is that possible? Or are the approaches being
described mutually incompatible?
________________________________________________________________________________
| From: | "Paul Messinger" <paulm(at)olypen.com> |
| Subject: | Re: Making real world sense of the OVP thread |
WOW lots to reply to. I will get around to all in the next few days. After
all there is life outside this list.
The below statement that ALL incidents were operator induced needs
justification!.
Bob please tell us where you got that information??? The GM at Van's was not
aware of any such conclusion. I was told only thing they knew was that all
alternator failures were associated with the use of any brand of OVP added
to the factory recommended electrical design. Both Crowbar and open circuit
designs that triggered on an OVP was the common element. The alternators had
failed after an OVP event. Who knows if the failure was the reason for the
event or the event caused the failure.
Its easy to say Van's is selling substandard alternators but this is not a
supportable conclusion based on the available facts.
I have seen NO data that; any, or some, or many, and certainly not ALL,
events were the result of operator actions. Since vans does not know and not
all failures were from Bob's OVP just how do all the failures become
operator induced.
That Bob's OVP is prone to false tripping (both from owner reports and
suggested on the last page of the do it your self builders instructions on
Bob's site) and that does not seem to harm some non Van's sourced
alternators leans to a conclusion that perhaps Van's alternators are somehow
poor quality. Lets NOT jump to conclusions. Has the Van's recommended wiring
been evaluated to see just what can happen and how this causes alternator
failures?? If so lets see the analysis.
The only conclusion the GM at Van's had made (or at least what I was told in
a personal conversation) was that the addition of a "B" lead contactor as
recommended in this list is the common element.
I have opened the "B" lead contactor under loads of 40 amps dozens (perhaps
over 100 times with ZERO damage. This during the load dump testing. NO
protection to the stock alternator was used. Then the load dump was clamped
with a simple transorb and the OV was tamed from 40+ volts to under 24V or
under 22 volts or under 20v depending on the transorb voltage rating.
Yes John its a poor design (or what ever) if the simple event of turning off
of a switch can fail any thing. Loss of that function should be fully
restored when the switch is turned back on. Its a simply unacceptable design
in any aircraft.
Turning a current producing alternator off (internal or external regulated)
stresses the alternator. The weakest part of the alternator is the internal
regulator if installed. Then there are the rectifier diodes (at least 6)
that have ratings unknown to most of us that can be stressed and fail.
An alternator is a current source and has internal energy that must be
externally loaded to control the voltage. This energy exists AFTER a
functioning regulator senses OV and turns off field current, this is the
classic load dump which is normal and designed for in alternators) If you
completely remove the load the voltage can exceed 100V in a very short time
and several hundred volts is possible. The internal diodes will exceed their
reverse voltage rating and clamp the voltage. Usually that is all that
happens as the voltage peak is sharp and the diodes can absorb the energy
with no damage.
Back 40-50 years ago alternators always had external regulators and there
was a mod kit that replaced the regulator with a different regulator box
that upped the alternator voltage to 120V for power tools. I still have such
a kit around here somewhere.
If there is an internal regulator it is the first line of defense and ALL
the regulators I have seen either have a built in transorb and / or require
an external transorb in addition. ALL alternators I have taken apart have
such protection. ALL alternators I have tested have not failed with a simple
opening of the "B" lead with loads of up to 40 amps. However my use of ALL
is meaningless as my testing includes 4 brands but only one or two of each
brand. Far less than needed for ALL to be used. I simply used the term ALL
to point out what a poor term it is in general conversation.
In any event there is a generic design error in every schematic where the
"B" lead contactor and an internally regulated alternator is shown. Also
every externally regulated alternator should seriously consider the same
correction.
The addition of one or more parallel transorbs (based on alternator amp
capacity) should be connected from the "B" lead to ground. The circuit path
is as follows.
The alternator "B" lead connection to the inline alternator fuse.
From the acft side of the fuse to ground are the transorbs.**
Then comes the "B" lead concoctor if there is one.
Finally the acft system connection for the alternator.
** some will argue the transorbs should be on the alternator side of the
fuse. The belt and suspenders designer may want have both sides protected.
The need for these trasnsorbs is additional protection for the alternator in
case the internal regulator gets a larger load dump than its designed for
and or to protect the alternator rectifier diodes if the voltage goes that
high which is likely if the regulator is external.
The transorbs are quite capable of blowing the Fuse if the tranorbs and fuse
are properly matched. Big transorbs and a fast blow fuse for starters.
The "B" lead contactor and OVP is eliminated with this configuration.
No false tripping based on an overly sensitive design.
Load dump protection in a no battery mode of operation.
Costs about the same but lighter in weight than the contactor.
NO huge current pulse thru the CB.
May not work when worst case design is performed with all types of
alternator failures; but an idea worth considering.
Just thinking out load to see the reaction. :-)
Paul
----- Original Message -----
From: "John Swartout" <jgswartout(at)earthlink.net>
Subject: RE: AeroElectric-List: Making real world sense of the OVP thread
>
>
>
> -----Original Message-----
> From: owner-aeroelectric-list-server(at)matronics.com
> [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of
> Andrew Rowley
> To: aeroelectric-list(at)matronics.com
> Subject: Re: AeroElectric-List: Making real world sense of the OVP
> thread
>
>
>
> Robert L. Nuckolls, III wrote:
>
>> The only component at-risk when internally regulated alternators
>> are wired per Z-24 is the alternator itself. To date, ALL
> incidents
>> of damage to the alternator using Z-24 architecture have been
>> operator induced. I.e., the alternator was turned OFF while
>> carrying a significant load.
>>
>> An internally regulated alternator with a b-lead contactor
>> is at risk for this form of damage irrespective of the form
>> of OV protection. In this case, the transient that damaged
>> the alternator was a function of manipulation of controls
>> . . . the OV protection system was not a participant.
>
> This is one thing that concerns me. Before I read this list I was not
> aware that the alternator could be damaged by turning it off. It seems
> to me that eliminating this possibility should be an major goal in
> designing these systems.
>
> Switching a switch off should turn off any items dependent on the
> switch. Switching it on should turn them on. Anything else (especially
> damage) violates the principle of least astonishment.
>
> --
> Andrew Rowley
> arowley(at)ncable.net.au
>
> I *think* this begins to explain why the experts favor externally
> regulated alternators. I'm now re-thinking my plan to use the
> internally-regulated alternator into which I've already invested nearly
> $200.
>
> John
>
>
>
________________________________________________________________________________
Received-SPF: softfail (mta2: domain of transitioning trigo(at)mail.telepac.pt does
not designate 85.138.31.240 as permitted sender) receiver=mta2; client_ip=85.138.31.240;
envelope-from=trigo(at)mail.telepac.pt;
| From: | "Carlos Trigo" <trigo(at)mail.telepac.pt> |
Can anybody tell me what is the "OBAM aircraft comunity"
Carlos Trigo
Portugal
________________________________________________________________________________
| From: | BobsV35B(at)aol.com |
| Subject: | Re: Making real world sense of the OVP |
In a message dated 4/1/2005 9:09:51 A.M. Central Standard Time,
marknlisa(at)hometel.com writes:
While I'm glad this discussion continues online, I find my limited time
competing with my desire to learn. I would ask for some brevity among
the contributers to the discussion. In pursuit of that goal I have a
couple of suggestions:
Good Morning Mark,
May I respectfully ask that you let the participants decide how much of
THEIR valuable time they wish to spend discussing the issue ONLINE?
I want to hear what they have to say whether I understand it or not.
If all we want is a cookie cutter device that can be purchased and applied,
we can just wait until we see it advertised and apply it to our projects at
that time.
It is my opinion that we are very privileged to be able to watch the process
that leads to the development of acceptable systems.
I'm happy the way it is!
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
Stearman N3977A
Brookeridge Airpark LL22
Downers Grove, IL 60516
630 985-8502
________________________________________________________________________________
| From: | BobsV35B(at)aol.com |
In a message dated 4/1/2005 10:21:10 A.M. Central Standard Time,
trigo(at)mail.telepac.pt writes:
Can anybody tell me what is the "OBAM aircraft comunity"
Owner Built And Maintained aircraft community.
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
Stearman N3977A
Brookeridge Airpark LL22
Downers Grove, IL 60516
630 985-8502
________________________________________________________________________________
| From: | "Troy Scott" <tscott1217(at)bellsouth.net> |
| Subject: | unreliable Rose ignition?? |
Larry,
After reading the following post I have to ask (since I have TWO Rose
ingitions) What's unreliable about yours?
Regards,
Troy Scott
"I'm considering replacing my unreliable Rose elec ign with another slick
mag. Is there any crime in having two impulse mags so I don't have to
rely on the operator to keep the non-impulse mag off while cranking? Or
is there a better way?
Starter and both ignitions are each on toggle switches.
Thanks,
Larry Bowen, RV-8/O-360"
________________________________________________________________________________
| From: | "Jerry Grimmonpre" <jerry(at)mc.net> |
| Subject: | Re: Making real world sense of the OVP thread |
Paul, Bob, listers ...
After reading Paul's note this thought crossed my mind. Assume an
alternator is beginning to drive towards OV. Wouldn't it be effective to
have the field made up of 2, 3, 4 or more winding circuits? As the OV
increases, have more field circuits electronically opened. As these
circuits open they "cool" down the output so other protection features are
able to catch up, putting a lid on frying $high$ stacks of electronics. It
seems this approach could be done in a more simple way electronically, but
that's not in my vocabulary. What is missed in this approach? I know
nothing about + to - .... or is it - to +?
Regards ...
Jerry Grimmonpre
----- Original Message -----
From: "Paul Messinger" <paulm(at)olypen.com>
Subject: Re: AeroElectric-List: Making real world sense of the OVP thread
>
>
> WOW lots to reply to. I will get around to all in the next few days. After
> all there is life outside this list.
>
> The below statement that ALL incidents were operator induced needs
> justification!.
>
> Bob please tell us where you got that information??? The GM at Van's was
> not
> aware of any such conclusion. I was told only thing they knew was that all
> alternator failures were associated with the use of any brand of OVP added
> to the factory recommended electrical design. Both Crowbar and open
> circuit
> designs that triggered on an OVP was the common element. The alternators
> had
> failed after an OVP event. Who knows if the failure was the reason for the
> event or the event caused the failure.
>
> Its easy to say Van's is selling substandard alternators but this is not a
> supportable conclusion based on the available facts.
>
> I have seen NO data that; any, or some, or many, and certainly not ALL,
> events were the result of operator actions. Since vans does not know and
> not
> all failures were from Bob's OVP just how do all the failures become
> operator induced.
>
> That Bob's OVP is prone to false tripping (both from owner reports and
> suggested on the last page of the do it your self builders instructions on
> Bob's site) and that does not seem to harm some non Van's sourced
> alternators leans to a conclusion that perhaps Van's alternators are
> somehow
> poor quality. Lets NOT jump to conclusions. Has the Van's recommended
> wiring
> been evaluated to see just what can happen and how this causes alternator
> failures?? If so lets see the analysis.
>
> The only conclusion the GM at Van's had made (or at least what I was told
> in
> a personal conversation) was that the addition of a "B" lead contactor as
> recommended in this list is the common element.
>
> I have opened the "B" lead contactor under loads of 40 amps dozens
> (perhaps
> over 100 times with ZERO damage. This during the load dump testing. NO
> protection to the stock alternator was used. Then the load dump was
> clamped
> with a simple transorb and the OV was tamed from 40+ volts to under 24V or
> under 22 volts or under 20v depending on the transorb voltage rating.
>
> Yes John its a poor design (or what ever) if the simple event of turning
> off
> of a switch can fail any thing. Loss of that function should be fully
> restored when the switch is turned back on. Its a simply unacceptable
> design
> in any aircraft.
>
> Turning a current producing alternator off (internal or external
> regulated)
> stresses the alternator. The weakest part of the alternator is the
> internal
> regulator if installed. Then there are the rectifier diodes (at least 6)
> that have ratings unknown to most of us that can be stressed and fail.
>
> An alternator is a current source and has internal energy that must be
> externally loaded to control the voltage. This energy exists AFTER a
> functioning regulator senses OV and turns off field current, this is the
> classic load dump which is normal and designed for in alternators) If you
> completely remove the load the voltage can exceed 100V in a very short
> time
> and several hundred volts is possible. The internal diodes will exceed
> their
> reverse voltage rating and clamp the voltage. Usually that is all that
> happens as the voltage peak is sharp and the diodes can absorb the energy
> with no damage.
>
> Back 40-50 years ago alternators always had external regulators and there
> was a mod kit that replaced the regulator with a different regulator box
> that upped the alternator voltage to 120V for power tools. I still have
> such
> a kit around here somewhere.
>
> If there is an internal regulator it is the first line of defense and ALL
> the regulators I have seen either have a built in transorb and / or
> require
> an external transorb in addition. ALL alternators I have taken apart have
> such protection. ALL alternators I have tested have not failed with a
> simple
> opening of the "B" lead with loads of up to 40 amps. However my use of ALL
> is meaningless as my testing includes 4 brands but only one or two of each
> brand. Far less than needed for ALL to be used. I simply used the term ALL
> to point out what a poor term it is in general conversation.
>
> In any event there is a generic design error in every schematic where the
> "B" lead contactor and an internally regulated alternator is shown. Also
> every externally regulated alternator should seriously consider the same
> correction.
>
> The addition of one or more parallel transorbs (based on alternator amp
> capacity) should be connected from the "B" lead to ground. The circuit
> path
> is as follows.
>
> The alternator "B" lead connection to the inline alternator fuse.
>
> From the acft side of the fuse to ground are the transorbs.**
>
> Then comes the "B" lead concoctor if there is one.
>
> Finally the acft system connection for the alternator.
>
> ** some will argue the transorbs should be on the alternator side of the
> fuse. The belt and suspenders designer may want have both sides
> protected.
>
> The need for these trasnsorbs is additional protection for the alternator
> in
> case the internal regulator gets a larger load dump than its designed for
> and or to protect the alternator rectifier diodes if the voltage goes that
> high which is likely if the regulator is external.
>
> The transorbs are quite capable of blowing the Fuse if the tranorbs and
> fuse
> are properly matched. Big transorbs and a fast blow fuse for starters.
>
> The "B" lead contactor and OVP is eliminated with this configuration.
>
> No false tripping based on an overly sensitive design.
>
> Load dump protection in a no battery mode of operation.
>
> Costs about the same but lighter in weight than the contactor.
>
> NO huge current pulse thru the CB.
>
> May not work when worst case design is performed with all types of
> alternator failures; but an idea worth considering.
>
> Just thinking out load to see the reaction. :-)
>
> Paul
>
> ----- Original Message -----
> From: "John Swartout" <jgswartout(at)earthlink.net>
> To:
> Subject: RE: AeroElectric-List: Making real world sense of the OVP thread
>
>
>>
>>
>>
>> -----Original Message-----
>> From: owner-aeroelectric-list-server(at)matronics.com
>> [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of
>> Andrew Rowley
>> To: aeroelectric-list(at)matronics.com
>> Subject: Re: AeroElectric-List: Making real world sense of the OVP
>> thread
>>
>>
>>
>> Robert L. Nuckolls, III wrote:
>>
>>> The only component at-risk when internally regulated alternators
>>> are wired per Z-24 is the alternator itself. To date, ALL
>> incidents
>>> of damage to the alternator using Z-24 architecture have been
>>> operator induced. I.e., the alternator was turned OFF while
>>> carrying a significant load.
>>>
>>> An internally regulated alternator with a b-lead contactor
>>> is at risk for this form of damage irrespective of the form
>>> of OV protection. In this case, the transient that damaged
>>> the alternator was a function of manipulation of controls
>>> . . . the OV protection system was not a participant.
>>
>> This is one thing that concerns me. Before I read this list I was not
>> aware that the alternator could be damaged by turning it off. It seems
>> to me that eliminating this possibility should be an major goal in
>> designing these systems.
>>
>> Switching a switch off should turn off any items dependent on the
>> switch. Switching it on should turn them on. Anything else (especially
>> damage) violates the principle of least astonishment.
>>
>> --
>> Andrew Rowley
>> arowley(at)ncable.net.au
>>
>> I *think* this begins to explain why the experts favor externally
>> regulated alternators. I'm now re-thinking my plan to use the
>> internally-regulated alternator into which I've already invested nearly
>> $200.
>>
>> John
>>
>>
>>
>
>
>
________________________________________________________________________________
| From: | B Tomm <fvalarm(at)rapidnet.net> |
| Subject: | Making real world sense of the OVP thread |
Paul,
Great post, I appreciate your time spent on this, even though my brain
flirts with it's own OVP event just in trying to follow it all. (good
thing it's internally regulated) LOL
Question. Do you suggest deleting the Alt contactor when using the inline
fuse and transorbs instead of Bob's OVP design? Without the contactor,
would we not be able to manually take the alt off line once it is
operating?
Bevan
-----Original Message-----
From: Paul Messinger [SMTP:paulm(at)olypen.com]
Subject: Re: AeroElectric-List: Making real world sense of the OVP thread
WOW lots to reply to. I will get around to all in the next few days. After
all there is life outside this list.
The below statement that ALL incidents were operator induced needs
justification!.
Bob please tell us where you got that information??? The GM at Van's was
not
aware of any such conclusion. I was told only thing they knew was that all
alternator failures were associated with the use of any brand of OVP added
to the factory recommended electrical design. Both Crowbar and open circuit
designs that triggered on an OVP was the common element. The alternators
had
failed after an OVP event. Who knows if the failure was the reason for the
event or the event caused the failure.
Its easy to say Van's is selling substandard alternators but this is not a
supportable conclusion based on the available facts.
I have seen NO data that; any, or some, or many, and certainly not ALL,
events were the result of operator actions. Since vans does not know and
not
all failures were from Bob's OVP just how do all the failures become
operator induced.
That Bob's OVP is prone to false tripping (both from owner reports and
suggested on the last page of the do it your self builders instructions on
Bob's site) and that does not seem to harm some non Van's sourced
alternators leans to a conclusion that perhaps Van's alternators are
somehow
poor quality. Lets NOT jump to conclusions. Has the Van's recommended
wiring
been evaluated to see just what can happen and how this causes alternator
failures?? If so lets see the analysis.
The only conclusion the GM at Van's had made (or at least what I was told
in
a personal conversation) was that the addition of a "B" lead contactor as
recommended in this list is the common element.
I have opened the "B" lead contactor under loads of 40 amps dozens (perhaps
over 100 times with ZERO damage. This during the load dump testing. NO
protection to the stock alternator was used. Then the load dump was clamped
with a simple transorb and the OV was tamed from 40+ volts to under 24V or
under 22 volts or under 20v depending on the transorb voltage rating.
Yes John its a poor design (or what ever) if the simple event of turning
off
of a switch can fail any thing. Loss of that function should be fully
restored when the switch is turned back on. Its a simply unacceptable
design
in any aircraft.
Turning a current producing alternator off (internal or external regulated)
stresses the alternator. The weakest part of the alternator is the internal
regulator if installed. Then there are the rectifier diodes (at least 6)
that have ratings unknown to most of us that can be stressed and fail.
An alternator is a current source and has internal energy that must be
externally loaded to control the voltage. This energy exists AFTER a
functioning regulator senses OV and turns off field current, this is the
classic load dump which is normal and designed for in alternators) If you
completely remove the load the voltage can exceed 100V in a very short time
and several hundred volts is possible. The internal diodes will exceed
their
reverse voltage rating and clamp the voltage. Usually that is all that
happens as the voltage peak is sharp and the diodes can absorb the energy
with no damage.
Back 40-50 years ago alternators always had external regulators and there
was a mod kit that replaced the regulator with a different regulator box
that upped the alternator voltage to 120V for power tools. I still have
such
a kit around here somewhere.
If there is an internal regulator it is the first line of defense and ALL
the regulators I have seen either have a built in transorb and / or require
an external transorb in addition. ALL alternators I have taken apart have
such protection. ALL alternators I have tested have not failed with a
simple
opening of the "B" lead with loads of up to 40 amps. However my use of ALL
is meaningless as my testing includes 4 brands but only one or two of each
brand. Far less than needed for ALL to be used. I simply used the term ALL
to point out what a poor term it is in general conversation.
In any event there is a generic design error in every schematic where the
"B" lead contactor and an internally regulated alternator is shown. Also
every externally regulated alternator should seriously consider the same
correction.
The addition of one or more parallel transorbs (based on alternator amp
capacity) should be connected from the "B" lead to ground. The circuit path
is as follows.
The alternator "B" lead connection to the inline alternator fuse.
>From the acft side of the fuse to ground are the transorbs.**
Then comes the "B" lead concoctor if there is one.
Finally the acft system connection for the alternator.
** some will argue the transorbs should be on the alternator side of the
fuse. The belt and suspenders designer may want have both sides protected.
The need for these trasnsorbs is additional protection for the alternator
in
case the internal regulator gets a larger load dump than its designed for
and or to protect the alternator rectifier diodes if the voltage goes that
high which is likely if the regulator is external.
The transorbs are quite capable of blowing the Fuse if the tranorbs and
fuse
are properly matched. Big transorbs and a fast blow fuse for starters.
The "B" lead contactor and OVP is eliminated with this configuration.
No false tripping based on an overly sensitive design.
Load dump protection in a no battery mode of operation.
Costs about the same but lighter in weight than the contactor.
NO huge current pulse thru the CB.
May not work when worst case design is performed with all types of
alternator failures; but an idea worth considering.
Just thinking out load to see the reaction. :-)
Paul
----- Original Message -----
From: "John Swartout" <jgswartout(at)earthlink.net>
Subject: RE: AeroElectric-List: Making real world sense of the OVP thread
>
>
>
> -----Original Message-----
> From: owner-aeroelectric-list-server(at)matronics.com
> [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of
> Andrew Rowley
> To: aeroelectric-list(at)matronics.com
> Subject: Re: AeroElectric-List: Making real world sense of the OVP
> thread
>
>
>
> Robert L. Nuckolls, III wrote:
>
>> The only component at-risk when internally regulated alternators
>> are wired per Z-24 is the alternator itself. To date, ALL
> incidents
>> of damage to the alternator using Z-24 architecture have been
>> operator induced. I.e., the alternator was turned OFF while
>> carrying a significant load.
>>
>> An internally regulated alternator with a b-lead contactor
>> is at risk for this form of damage irrespective of the form
>> of OV protection. In this case, the transient that damaged
>> the alternator was a function of manipulation of controls
>> . . . the OV protection system was not a participant.
>
> This is one thing that concerns me. Before I read this list I was not
> aware that the alternator could be damaged by turning it off. It seems
> to me that eliminating this possibility should be an major goal in
> designing these systems.
>
> Switching a switch off should turn off any items dependent on the
> switch. Switching it on should turn them on. Anything else (especially
> damage) violates the principle of least astonishment.
>
> --
> Andrew Rowley
> arowley(at)ncable.net.au
>
> I *think* this begins to explain why the experts favor externally
> regulated alternators. I'm now re-thinking my plan to use the
> internally-regulated alternator into which I've already invested nearly
> $200.
>
> John
>
>
________________________________________________________________________________
| Subject: | Re: Making real world sense of the OVP thread |
| From: | "Matt Prather" <mprather(at)spro.net> |
Hi Paul,
Embeded comment.
>
>
> WOW lots to reply to. I will get around to all in the next few days.
> After all there is life outside this list.
>
snip
>
> Yes John its a poor design (or what ever) if the simple event of turning
> off of a switch can fail any thing. Loss of that function should be
> fully restored when the switch is turned back on. Its a simply
> unacceptable design in any aircraft.
>
I can think of a number of controls on an aircraft that shouldn't be adjusted
during certain normal regimes of operation. Most people consider these
limitations acceptable. Just consider the ignition/starter switch. Once the
engine is running, most/all aircraft will likely incur some damage if the
starter
is re-engaged. Similarly, if the ignition is turned off when the engine
is at a
high power setting, it may backfire vigorously enough to damage intake and
exhaust components. Or how about the flap actuation switch? If you move
the electric flap switch to full down while at cruise speeds, structure
damage
may occur. In each of these cases, technology could be applied to make
the system more idiot proof. In the majority of cases nothing has been done
beyond attempting to train the operator.
I like the idea that a system can be made more operator fault tolerant.
However,
there are many systems that aren't, and I don't think they are all considered
examples of poor design. Though some actually are poor designs, many
were the state of the art at the time of development.
Similarly, I think I might like an airplane that were smart enough to not
let me
get into a situation where I could crash it. At the current state of the
art, that
might be possible, but I bet I couldn't afford to buy such an airplane.
I realize you have suggested relatively low cost solutions to enhance
electrical
system performance, and I applaud that. Will you work on my Cessna flap
switch when you get some free time?? Just kidding.
Regards,
Matt-
________________________________________________________________________________
| From: | Jim Oke <wjoke(at)shaw.ca> |
| Subject: | Re: Making real world sense of the OVP thread |
Let's keep an eye on the big picture in all this.
The devices under discussion are generally alternators designed for
automotive or similar applications.
Automobile electrical system designers avoid the "accidentally turned off
alternator while under load" situation by simply NOT providing such a
capability. The alternator system is (usually) transparent to the operator
safe for a "no charge" warning light or sometimes a voltmeter. No auto that
I have ever seen has an "alternator on/off" switch within easy reach of the
driver that has to be operated during every start-run-stop cycle; automobile
buyers would simply not stand for it.
Using these automotive alternators in an aircraft application involves some
cost vs. capability compromises. That is, taking advantage of the low cost
of a mass-produced automotive alternator means dealing with a few potential
shortcomings of the device when it is used in an aviation application. If
the bother of correcting these problems is not worth the cost savings, then
move on to some other solution. This could be, for instance, an alternator
designed with aviation use in mind (with the price tag associated with low
volume, highly regulated, production.)
The "crowbar OVP with B contactor" system is one reasonably cost effective
way with dealing with a potentially serious over-volt problem when using
such an automotive alternator in an aviation application. Let's keep in
focus the dollars involved. Spending $50 to prevent a $200 alternator from
frying $2000 worth of avionics is not a bad value, IMHO. (I would also
suggest that $2000 is at the low end of many system proposed - dual GNS
430s, EFIS, engine monitors, etc.).
Placing a $200 alternator at some limited risk to safeguard some very $$$
avionics seems like reasonable risk management to me.
Jim Oke
Wpg., MB
----- Original Message -----
From: "Andrew Rowley" <arowley(at)ncable.net.au>
Subject: Re: AeroElectric-List: Making real world sense of the OVP thread
>
>
> Robert L. Nuckolls, III wrote:
>
>> The only component at-risk when internally regulated alternators
>> are wired per Z-24 is the alternator itself. To date, ALL incidents
>> of damage to the alternator using Z-24 architecture have been
>> operator induced. I.e., the alternator was turned OFF while
>> carrying a significant load.
>>
>> An internally regulated alternator with a b-lead contactor
>> is at risk for this form of damage irrespective of the form
>> of OV protection. In this case, the transient that damaged
>> the alternator was a function of manipulation of controls
>> . . . the OV protection system was not a participant.
>
> This is one thing that concerns me. Before I read this list I was not
> aware that the alternator could be damaged by turning it off. It seems
> to me that eliminating this possibility should be an major goal in
> designing these systems.
>
> Switching a switch off should turn off any items dependent on the
> switch. Switching it on should turn them on. Anything else (especially
> damage) violates the principle of least astonishment.
>
>
> --
> Andrew Rowley
> arowley(at)ncable.net.au
>
>
>
________________________________________________________________________________
Hi all,
I would appreciate your opinion about the following point :
In our Rotax 914 powered MCR 4S, the only electrical noise audible is
from the small RAC Trim in the right aileron, not far from the Bob
Archer's VHF antenna in the wingtip. This is not a real nuisance, since
the aileron trim is seldom used in flight.
Nevertheless would a capacitor across the trim motor wires improve things ?
Thanks for your advice,
Regards,
Gilles Thesee
Grenoble, France
________________________________________________________________________________
| From: | Pascal Gosselin <pascal(at)aeroteknic.com> |
| Subject: | Clifton/Litton Vector Resolver (KI-206) |
The resolver on my KI-206 CDI is on the fritz.
It's a Clifton/Litton TWH-11-F-08/B189 VECTOR RESOLVER.
or that could be TWH-ii-F-08/B189
Waiting for a quote on unknown equivalent Bendix-King part but it's
apparently horrendously expensive. Anybody know of another source ?
This is my HSI backup and the LOC/GS work fine so I'm reluctant to invest in
(tuning VORs is something I do only when I am *very* bored).
-Pascal
+---------------------------+
Pascal Gosselin
pascal(at)aeroteknic.com
tel. (450) 676-6299
fax. (450) 676-2760
cell. (514) 298-3343
________________________________________________________________________________
| From: | Andrew Rowley <arowley(at)ncable.net.au> |
| Subject: | Re: Making real world sense of the OVP thread |
Matt Prather wrote:
> I can think of a number of controls on an aircraft that shouldn't be adjusted
> during certain normal regimes of operation. Most people consider these
> limitations acceptable. Just consider the ignition/starter switch. Once the
> engine is running, most/all aircraft will likely incur some damage if the
> starter
> is re-engaged. Similarly, if the ignition is turned off when the engine
> is at a
> high power setting, it may backfire vigorously enough to damage intake and
> exhaust components. Or how about the flap actuation switch? If you move
> the electric flap switch to full down while at cruise speeds, structure
> damage
> may occur. In each of these cases, technology could be applied to make
> the system more idiot proof. In the majority of cases nothing has been done
> beyond attempting to train the operator.
That's true, however the measure should be whether the average user
would expect the result. Flap speeds are well known and learnt by every
pilot. Alternator characteristics are less so, particularly when you
have different types - internally regulated vs. external etc.
Essentially, the results of switching a switch should not be a surprise.
They should be reasonable obvious. If I turn the alternator off, it is
not a surprise if I end up with a flat battery. It is a surprise if I
end up with a damaged alternator.
Ignition - you can switch the ignition off one at a time at cruise power
without a problem. If doing that damaged the magneto, it would be a problem.
--
Andrew Rowley
arowley(at)ncable.net.au
________________________________________________________________________________
| Subject: | Re: Making real world sense of the OVP thread |
Andrew,
I use to check the low voltage warning light at the run up area by
switching the ALT half of the rocker switch off in the Cessnas I use to fly. Was
or is that a bad practice? John Robinson RV-7A...electrical and gauges.
________________________________________________________________________________
| From: | Andrew Rowley <arowley(at)ncable.net.au> |
| Subject: | Re: Making real world sense of the OVP thread |
Bikcrzy(at)aol.com wrote:
> I use to check the low voltage warning light at the run up area by
> switching the ALT half of the rocker switch off in the Cessnas I use to fly.
Was
> or is that a bad practice? John Robinson RV-7A...electrical and gauges.
I don't know - I am learning this stuff from the list as much as anyone
else. I THINK that it is OK because the alternator is externally
regulated, and you are turning off the field rather than disconnecting
the alternator from the load, but I am not sure. Hopefully someone else
will have better information.
If this is the case it is another reason to try to design systems so
that turning off the alternator does not cause damage - if it is OK in
the aircraft people learn in, they are more likely to do it in other
aircraft.
--
Andrew Rowley
arowley(at)ncable.net.au
________________________________________________________________________________
| From: | "Gordon or Marge Comfort" <gcomfo(at)tc3net.com> |
| Subject: | flight over Wichita/battery,contactor location |
Gordon, Haven't heard from you in some time my friend.
Have you considered e or p-mags?
Say hi to Marge.
Bob . . .
Bob: Cruised by Wichita Monday last. We left Tucson at 06:20MST and
landed at Adrian, MI (ADG)at 18:10EST with two stops. Most of the trip
was at 9500'. The air was surprisingly smooth at altitude but there was
significant turbulence on landing in Missouri and Michigan.
Questions: If I place the battery (RV-8)aft of the baggage compartment
along with the contacter are there reasons other than weight (and
work)not to put the starter contacter there as well? It would mean
bringing a buss lead forward and if I decide to add electric heating
(garments or seats) a 60A alternator and probably a 6AWG buss lead would
be required. If this is done, how best to provide protection for the
buss lead? Should a temperature sensor be used with the LR-3?
Hope to see you at Oshkosh.
Gordon Comfort
N363GC
________________________________________________________________________________
| From: | "Fergus Kyle" <VE3LVO(at)rac.ca> |
| Subject: | VHF tape antenna |
"
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: AeroElectric-List: Antenna / aerial questions
>>
>Dear Bob et al>
>The radio antenna kit supplied by the manufacturer of my kit contains 6m
>of RG58C/U cable. It also contains some copper tape for the
>manufacturing of a dipole antenna in the rear of the fin. Toroids were
>also supplied and the aircraft is of fibreglass construction.>
>1) Considering cost/benefit etc, would I be wise to use RG400 cable
>instead ?>
>2) Instead of using the copper tape (others have reported it cracking
>after a while from temp changes), would it be okay to bring the inner
>part of the aerial cable out through the braid and make the dipole of
>these two cable components rather than other material ?>
>3) Use the toroids or not ?
tens of thousands of airplanes are flying with RG-58 in the
VHF comm system . . . The toroids don't do much but they
don't hurt either.
I've often wondered how well thin foil antennas perform when
bonded directly to composite shells. The differences in
thermal coefficient of expansion will probably cause cracks.
The width of the foil is a plus as it improves bandwidth of
the antenna. VHF comm has a greater spread of useful frequencies
(percentage wise) than any other service we use. The thin, flat
conductors are attractive. Making them out of copper makes them
solderable too.
Hmmmm . . . come to think of it, etched circuit board material
comes in big sheets of 0.062" fiberglas and epoxy with .0013"
copper sheet bonded to it. I've never heard any concern about
hairline cracks due to temperature cycling. I suspect your
worries don't have much foundation in physics. It's very
likely that your antenna assembled with the materials you
have will perform as expected for longer than you will
own the airplane. Bob . . ."
Cheers, all,
I am building the same kit as Kingsley and am using the supplied
copper tape per the instructions. As Bob says, the tape widens the range of
frequencies available but is susceptible to cracking if stuck to epoxy
stuff.
I slid the tape into an envelope of polythene and epoxied That
to the fin close-out, leaving the last two inches each end for trimming in
situ. Seems to work............
Ferg
Europa A064
________________________________________________________________________________
| From: | Hopperdhh(at)aol.com |
| Subject: | Re: Making real world sense of the OVP thread |
I haven't been on this list for very long, so forgive me if this has been
covered earlier, or if I'm misinformed.
I would think that turning off the alternator field even if the alternator
is at full output would do no damage to anything. There is no high voltage
transient, the battery just picks up the load as the system voltage drops to
12v or a little less. When the alternator field is turned back on, the
regulator should begin regulation as the voltage reaches its set point of 14 volts
or so. Now here is where a transient could happen, as we don't know what the
recovery characteristic of the regulator circuitry is, without an analysis of
the design of the regulator. Some experimental data here would be
necessary. I would especially like to know if a "linear" regulator would do as
well
as the switching type. A scope on the battery line should tell us this
information, but it would not necessarily hold for all regulators. I would report
the result of this experiment, except my RV-7A with the Vans 60 amp system
is in the paint shop for the next several weeks.
Now, if you were to disconnect the battery while it (the battery) was
drawing significant current, there is definitely a "load dump." The regulator
would turn off the field, but the alternator field current would take some time
to decay -- especially if a field diode in the regulator were recirculating
the field current. The diode extends the L/R time constant to about 200
milliseconds if memory serves me correctly. (Again, forgive me for not presenting
experimental data here.) During that time the system voltage could approach
40 to 60 volts (if there are no protective zeners, etc.) depending on the
rest of the load. This is what a "load dump" is -- at least in the automotive
world.
There is also the possibility that the battery might be necessary to
stabilize the regulator, alternator, battery, load loop. If that loop were to
begin
an oscillation it could easily exceed the design limits of the expensive
"load" components. This experiment would best be done in the lab using
something other than aircraft electronics for the load!
I will now revert back to reading and trying to catch up on this thread.
Regards,
Dan Hopper
hopperdhh (at) aol.com
Walton, IN
In a message dated 4/1/05 3:05:37 P.M. US Eastern Standard Time,
wjoke(at)shaw.ca writes:
Let's keep an eye on the big picture in all this.
The devices under discussion are generally alternators designed for
automotive or similar applications.
Automobile electrical system designers avoid the "accidentally turned off
alternator while under load" situation by simply NOT providing such a
capability. The alternator system is (usually) transparent to the operator
safe for a "no charge" warning light or sometimes a voltmeter. No auto that
I have ever seen has an "alternator on/off" switch within easy reach of the
driver that has to be operated during every start-run-stop cycle; automobile
buyers would simply not stand for it.
Using these automotive alternators in an aircraft application involves some
cost vs. capability compromises. That is, taking advantage of the low cost
of a mass-produced automotive alternator means dealing with a few potential
shortcomings of the device when it is used in an aviation application. If
the bother of correcting these problems is not worth the cost savings, then
move on to some other solution. This could be, for instance, an alternator
designed with aviation use in mind (with the price tag associated with low
volume, highly regulated, production.)
The "crowbar OVP with B contactor" system is one reasonably cost effective
way with dealing with a potentially serious over-volt problem when using
such an automotive alternator in an aviation application. Let's keep in
focus the dollars involved. Spending $50 to prevent a $200 alternator from
frying $2000 worth of avionics is not a bad value, IMHO. (I would also
suggest that $2000 is at the low end of many system proposed - dual GNS
430s, EFIS, engine monitors, etc.).
Placing a $200 alternator at some limited risk to safeguard some very $$$
avionics seems like reasonable risk management to me.
Jim Oke
Wpg., MB
----- Original Message -----
From: "Andrew Rowley" <arowley(at)ncable.net.au>
Subject: Re: AeroElectric-List: Making real world sense of the OVP thread
> --> AeroElectric-List message posted by: Andrew Rowley
>
>
> Robert L. Nuckolls, III wrote:
>
>> The only component at-risk when internally regulated alternators
>> are wired per Z-24 is the alternator itself. To date, ALL incidents
>> of damage to the alternator using Z-24 architecture have been
>> operator induced. I.e., the alternator was turned OFF while
>> carrying a significant load.
>>
>> An internally regulated alternator with a b-lead contactor
>> is at risk for this form of damage irrespective of the form
>> of OV protection. In this case, the transient that damaged
>> the alternator was a function of manipulation of controls
>> . . . the OV protection system was not a participant.
>
> This is one thing that concerns me. Before I read this list I was not
> aware that the alternator could be damaged by turning it off. It seems
> to me that eliminating this possibility should be an major goal in
> designing these systems.
>
> Switching a switch off should turn off any items dependent on the
> switch. Switching it on should turn them on. Anything else (especially
> damage) violates the principle of least astonishment.
>
>
> --
> Andrew Rowley
> arowley(at)ncable.net.au
>
>
>
________________________________________________________________________________
| From: | "Kelly Patterson" <kbob(at)cox.net> |
| Subject: | RE: PMags and RPM |
I'm a happy owner of an Emag and have spoken to the owners at length about
the E & P models. So I'll quote what I know from memory, which we know can
be flaky at times :)
They have a big following in the plastic plane arena, and are gathering
interest with the RV community. They did not indicate they monitor any
'lists', they are simply working hard to start a new business and answer
questions.
From what I understand about the PMag.which I don't own, but may someday.
The generator puts out 12-14V at approx. 1500 RPM, and drops voltage output
as the RPM drops. The PMag & Emag will still make spark at some ridiculous
low number like 5 V. So by generating 5+ V at 800 RPM it is self
sustaining. The deal is - it has no excess voltage that can charge a
battery below 1500 RPM, but it can help in a failed alternator situation
above that RPM. Of course the output would be a very low amperage, and I
wouldn't count on continued flight after an alternator failure.
That is the gist of it - no hard numbers - do some research on the website -
your mileage will vary - and I love this list and it's wealth of
information!
Kelly Patterson
RV-6A finishing & wiring
PHX, AZ
I think this sounds like a good question to ask the people that make the
PMags.
Does someone that plays a principle role in the company monitor the list?
Jim in Kelowna
----- Original Message -----
From: <owner-aeroelectric-list-server(at)matronics.com>
Subject: AeroElectric-List: PMags and RPM
>
> Listers - PMags appear to be a good way to go safety wise as it
> renders
> (in
> principle) ignition independent of the electrical system. But this only
> happens if RPM is high enough.
>
> In case of the unlikely scenario that the electrical system should die
> and the RPM should fall below PMag's self sustaining level, would wind
> milling by diving bring the engine RPM up sufficiently, thereby
> restoring engine power?
>
> A similar scenario would occur as one is on short final with engine at
> 800 RPM. If the electrical system is down, are we in a situation
> whereby the PMag could stop generating its own electricity, thereby
> committing the flight to a definitive landing no matter what, i.e. no
> go around possibility?
>
> Michle
> RV8 - Wings
________________________________________________________________________________
| From: | "Eric M. Jones" <emjones(at)charter.net> |
| Subject: | Re: Resistor for Crowbar-- calculation. |
Resistor for Crowbar---To keep the current within the 1000% range.
Basically we want to keep the peak current at 10X the rated current of the
circuit breaker, or 50 amps. If the voltage has risen to 16.2V, the resistor
must be 16.2/50=0.324 Ohms. Since the associated wiring and the circuit
breaker have SOME resistance, we can estimate that 0.250 ohms is probably
good enough to do the job.
Of course, this is on the upper safe-trip limit of the 5-amp circuit
breaker, and the lowest voltage that we still call over-voltage. What about
the sudden connection of dual batteries? What if the alternator goes
directly from 14.5 V to some unknown over-voltage? In that case 0.250 ohms
is probably on the small side.
A short word about resistorscarbon composition resistors are ideal for
pulses and surges, but they are becoming hard to get. Dont use metal film,
carbon thin-film, or plain wire-wound if you can avoid it. They are
inductive and/or develop hot spots that lead to failure. Carbon thick-film
or specially rated wire-wounds seems to be the choice for pulses.
Manufacturers frequently dont rate their resistors for overstress because
the materials used in their construction can vary batch-to-batch, and,
manufacturers can and do mechanically work the resistance elements to get
the required values.
Most resistors carry a continuous POWER rating in watts, but this does not
specify the ENERGY they are designed to handle. Electrical watts is
POWER=volts x amps. Electrical joules is ENERGY= power x time. Why do we
care? Usually I sq. x R is used to figure the resistor continuous power
dissipation, but in this case the resistor only sees a short pulse so we use
the energy equation of I sq. R x T, where T is the pulse time (yes, I know I
have played a little loose, but using a square-wave approximation allows for
some unknowns, and leads to a greater safety margin). So for I=50 A (our
desired limit); R=0.25 ohms (our assumed resistance), T=50 mS (a wild guess
pending additional testing) we get 31.3 joules (ENERGYsimilar to a strobe
flash).
Although you can measure resistances through a circuit breaker with an
ohmmeter, these reading are always suspect because it is through a contact
pair that will change resistance with every closure. I suspect this is at
the core of the extremely wide range of opening times in the manufacturers
data sheetsPublished trip time at 1000% Klixon 7274 is 0.046 to 0.800
secondsa 17X range. So I would choose to ignore measured CB resistance.
So how do we choose a resistor? We want 0.25 ohms or more. We want a
resistor that wont evaporate at 50A. So we can choose a resistor that has a
wattage rating that will give us these characteristics. Assuming that we
need a rating of 31.3 joules, that is power x time=31.3 joules. Then 31.3
joules /.050 Second=625 watts (almost a horsepower but only for some
milliseconds. There is currently a technical discussion attempting to find
out how many milliseconds would be typical.)
Assuming that we can buy a resistor that will carry 10X its continuous
rating for 5 seconds (a typical rating), we still need 62.5 watts of
resistor. There is a whole lot of excess here, but the manufacturers dont
specify for it.
Instead we can get resistors that are ENERGY rated to handle the 31.3
joules. These are ideal. Ohmite series 33J---4 parallel 1.0 ohm Ohmite
33J1R0 (Digikey 33J1R0-ND) is about 60 joules at 0.25 ohms. $1.08 each.
These are small and will fit the bill.
Doubtless, there are other ways of doing this job. Bob's earlier note on
this is reasonable but some numbers are still in the air. The discussion
continues.
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones(at)charter.net
"When dealing with the enemy, it helps if he thinks you're a little bit
crazy."
--Gen. Curtis LeMay
________________________________________________________________________________
| From: | Rick Girard <fly.ez(at)verizon.net> |
| Subject: | Re: VHF tape antenna |
All, I did a search about antenna failures when I was ready to put them
in my winglets. Almost all failures of antenna elements occurred when
the antenna was mounted on the gear legs of the Rutan canards and the
aircraft had an "arrival" which caused the gear to flex radically. Be
far the more common problem when mounting the antenna under the skin of
a vertical stab / winglet is for the glass to start to delaminate over
the antenna. As Bob states in his instruction manual, the foam and
e-glass are transparent to RF energy so there is no penalty for burying
the antenna below the glass skin in the foam. As for antenna elements,
if there is a rain gutter manufacturer near you that stocks copper, use
that. A few feet (it comes in 12" widths) will give you enough material
for all you antenna needs, and you can fatten the elements if you wish
to help make the SWR lower over a broader range of frequencies.
Rick Girard
________________________________________________________________________________
| From: | "Paul Messinger" <paulm(at)olypen.com> |
| Subject: | Re: Resistor for Crowbar-- calculation. |
Here is a well intended paper that makes reasonable assumptions that
unfortunately comes to potentially bad conclusions.
But first some comments about the OVP CB trip currents and duration
I am a worst case person as any design submitted for production or in our
case builders building from parts specified must either specify the exact
part and or work with any specified type or part meeting the general stated
values. Further the resulting module must be designed to work in the very
wide range of applications IE OBAM acft.
The problem comes when a test of two of the design is tested in a "typical"
system.
Here there is a wide range of module component variations based on parts
tolerances and then there is the acft system where more variables are
encountered.
The following numbers are approximate as I did not look up the exact values
and the exact value is not relevant to my point.
Bob ran a test of the OVP using a CB with a resistance of 0.36 ohms. He used
#20 wire, he used a 2 year old battery no longer suitable for flight. He
ended up with 135 amps current thru the CB and 15 milliseconds to open.
I ran a test of a my built-up version of the same OVP module. My CB a 7277
(Bob used a very similar 7274) was measures not at 0.36 ohms (the max
specification resistance but 0.010 ohms.
I used #4 (3 ft total and #6 wire 4 ft total and all bolted brass or copper
connections) (vs. Bob's #20 wire). My battery was dual PC-625 rated at 3.5
milliohms (Bob used a Panasonic rated new at 13 milliohms and it was not
new) My battery setup has a 3600 amp short circuit rating. My open time was
50-70 milliseconds. Higher current and longer times?? Seems not to make
sense but that comes later.
That I got 400 amps and Bob got 135 amps is reasonable and both of our tests
are reasonable system tests. My test was a near exact example of my real
acft.
Much discussion of 400 amps is not possible. Well Bob's circuit loop
resistance including the battery is several times mine so its reasonable to
me to get several times the current. The interested can go the math.
The CB specification has a huge range of tripping times based on CB
temperature and current. AT 50 amps the max current that in specification
for reuse the range 0.050 seconds to 0.800 seconds. Clearly not a precision
device. Its agreed the trip times will shorten with higher currents than 50
amps.
If you start with a 0.050 trip time at 50 amps I can see how it can get
under 0.020 seconds with a couple hundred amps. Bob has calculated the
thermal response but there is also a mechanical response that is much more
constant.
However if you start with 0.800 second trip time for 50 amps you never get
to 15 ms as BOB did with 135 amps, I suggest its still likely to be more
than 0.200 seconds. to trip.
My point is a single or even many different tests cannot determine the
results of all builders. Thus A worst case design analysis is required
before the design is ready for publication. Clearly this has never been
done. Both parts tolerance limits and temperature variations must be
included.
Worst case analysis approach example will be a soon to be posted white
paper.
Also good engineering design practice dictates parts derating and in this
case parts are overstress based on the component specifications. That a test
demonstrated that the part will work overstressed is no indication that any
part with the same specifications will work.
Now for some embedded comments to make my point,,,, see below
----- Original Message -----
From: "Eric M. Jones" <emjones(at)charter.net>
Subject: AeroElectric-List: Re: Resistor for Crowbar-- calculation.
>
>
> Resistor for Crowbar---To keep the current within the 1000% range.
>
> Basically we want to keep the peak current at 10X the rated current of the
> circuit breaker, or 50 amps. If the voltage has risen to 16.2V, the
> resistor
> must be 16.2/50=0.324 Ohms. Since the associated wiring and the circuit
> breaker have SOME resistance, we can estimate that 0.250 ohms is probably
> good enough to do the job.
Not valid as I have 3 CB's that have internal resistance of 0.010 to 0.012
ohms and a battery of 0.0035 ohms with low resistance wiring for a total
well under 0.050 total.
I suggest the minimum resistance additional resistance is at least 0.30 ohms
and that must include the tolerance of the added resistor.
> Most resistors carry a continuous POWER rating in watts, but this does not
> specify the ENERGY they are designed to handle. Electrical watts is
> POWER=volts x amps. Electrical joules is ENERGY= power x time. Why do we
> care? Usually I sq. x R is used to figure the resistor continuous power
> dissipation, but in this case the resistor only sees a short pulse so we
> use
> the energy equation of I sq. R x T, where T is the pulse time (yes, I know
> I
> have played a little loose, but using a square-wave approximation allows
> for
> some unknowns, and leads to a greater safety margin). So for I=50 A (our
> desired limit); R=0.25 ohms (our assumed resistance), T=50 mS (a wild
> guess
> pending additional testing) we get 31.3 joules (ENERGYsimilar to a strobe
> flash).
BUT if you use the specification value for the pulse with its NOT 0.050 its
0.800 or 16 times as much energy to deal with. IE 31.5 joules x 16 = 504
joules, not a small difference.
> Although you can measure resistances through a circuit breaker with an
> ohmmeter, these reading are always suspect because it is through a contact
> pair that will change resistance with every closure. I suspect this is at
> the core of the extremely wide range of opening times in the manufacturers
> data sheetsPublished trip time at 1000% Klixon 7274 is 0.046 to 0.800
> secondsa 17X range. So I would choose to ignore measured CB resistance.
No facts in evidence that is a factor as the maximum specified resistance in
the spec and used by Bob in his analysis. WE must use the values specified.
However the max resistance is given and there is no minimum resistance so
that means its reasonable to use zero for worst case so I finally conclude
you did it well! (I have parts in hand that are 1/3 of max specified
resistance)
>
> So how do we choose a resistor? We want 0.25 ohms or more. We want a
> resistor that wont evaporate at 50A. So we can choose a resistor that has
> a
> wattage rating that will give us these characteristics. Assuming that we
> need a rating of 31.3 joules, that is power x time=31.3 joules. Then 31.3
> joules /.050 Second=625 watts (almost a horsepower but only for some
> milliseconds. There is currently a technical discussion attempting to find
> out how many milliseconds would be typical.)
ANY use of typical in this analysis is out of line. The typical value is not
known and any use of it simple can result in a failure to design a reliable
circuit.
There is no data that allows the use of any time shorter hat 0.800 ms and
again times in the 50 ms or shorter may be what tests show but again that is
why good engineering never use a test to define the design, just to
demonstrate the concept.
So again we are short by a factor of 16 the needed power handling.
>
> Assuming that we can buy a resistor that will carry 10X its continuous
> rating for 5 seconds (a typical rating), we still need 62.5 watts of
> resistor. There is a whole lot of excess here, but the manufacturers dont
> specify for it.
15 milliseconds is perhaps usable for a pulse overload time but 800
milliseconds is a very long time for an internal part to have local heating
Thus use of the wattage rating is improper and usually leads to design
failures. As you point out next :-)
>
> Instead we can get resistors that are ENERGY rated to handle the 31.3
> joules. These are ideal. Ohmite series 33J---4 parallel 1.0 ohm Ohmite
> 33J1R0 (Digikey 33J1R0-ND) is about 60 joules at 0.25 ohms. $1.08 each.
> These are small and will fit the bill.
First we need more than 0.25 ohms +/- 5%. Thus the resistance can be 5%
lower or higher and that variation may be important depending on the design
margin.
However as I have shown the 31.3 joules is off by a factor of 16 (OK if the
battery loaded voltage drops to 8 V its still over loaded by a factor of 8.)
its still not a valid solution.
Then there is the math. The ohmite spec sheet says the energy rating is 12.7
and that is for 4 devices (50.8 joules) and the fusing joules is 53.26 x 4 =
213 joules. Note I previously stated that 31.3 was approx 8 times too low.
31.3 x 8 = 250.4 joules. 250 is larger than 213 the max value for fusing
(failure).
Thus the above parts based on my energy calculations and the spec sheet says
the parts will fuse and not handle the power.
Regardless this is the resistor class we must use if we determine that a
series resistor is needed. What Bob has suggested the ALSR-5 is not an
appropriate class of resistor. As Eric has pointed out this application
needs surge rated resistors as the design and construction of the resistor
is different.
If you want to ignore the worst case ratings please use the resistors Eric
has suggested as they will likely work and Bob's suggested resistors will
likely fail (even in the "Typical application).
I still feel the present approach of a crowbar and "B" lead contactor is not
a good solution regardless of circuit resistance or BC time to open etc.
Other issues yet to be addressed is the ability of the contacts in the "B"
lead contactor surviving with out welding closed and or the large energy
transients introduces into the system bus during this event.
I would be extremely surprised if this design had EVER needed to open a real
full runaway (the rarest of the rare failure modes) alternator vs. a high
output failure. Big difference in voltages and currents.
Paul
> Regards,
> Eric M. Jones
> www.PerihelionDesign.com
> 113 Brentwood Drive
> Southbridge MA 01550-2705
> Phone (508) 764-2072
> Email: emjones(at)charter.net
>
> "When dealing with the enemy, it helps if he thinks you're a little bit
> crazy."
> --Gen. Curtis LeMay
>
>
>
________________________________________________________________________________
| From: | "Vincent Welch" <welchvincent(at)hotmail.com> |
| Subject: | OVP etc - do we have a bottom line? |
A M E N ! ! !
>From: Richard Riley <Richard(at)RILEY.NET>
>Reply-To: aeroelectric-list(at)matronics.com
>To: aeroelectric-list(at)matronics.com
>Subject: AeroElectric-List: OVP etc - do we have a bottom line?
>Date: Fri, 01 Apr 2005 07:47:28 -0800
>
>
>I've now spent much of the night trying to read and understand all the
>objections to and defences of the crowbar OVP system.
>
>I still have no idea who's right. I just have a migraine.
>
>If I'm willing to spend enough money, can I build a system that satisfies
>all the critics? For example, many of the crowbar posts involve internally
>regulated alternators. If I'm using a B&C 60 amp alternator, an LR3, and
>SD8 and 2 batteries, am I still in danger of frying $50k worth of avionics
>because I blinked wrong?
>
>Please understand, I am willing to spend whatever it takes to make this
>problem (if it is a problem) go away. I don't want the "best" solution, I
>want all the solutions that are worthwhile and applicable. I'm not going
>to worry about an extra $100 for a transorb, I want belt and suspenders and
>nail gun and epoxy. Is that possible? Or are the approaches being
>described mutually incompatible?
>
>
________________________________________________________________________________
| From: | "Joe & Jan Connell" <jconnell(at)rconnect.com> |
| Subject: | A question about P-Mags when engine is windmilling |
Guys,
Here is Brad Dement's response regarding the question.
Joe Connell
Stewartville, MN
RV-9A, N95JJ, wiring
----- Original Message -----
From: Brad Dement
Subject: RE: A question about P-Mags when engine is windmilling
Hi Joe:
The primary operating goal for the P-MAG is to keep the engine running in the event
of in-flight electrical power loss. It is designed to operate at in-flight
idle (final approach) speeds of less than 1000 rpm. P-MAGs commonly operate
at 700 rpm, and often less.
If a particular craft is known to have an in-flight idle below the speed the P-MAG
alternator will sustain the ignition, it should be noted by the pilot so if
such conditions are encountered, he knows not to operate there.
This minimum P-MAG speed is easy to ascertain on the ground. Your ground idle
will be significantly less than your in-flight idle. When doing a run up, simply
turn to the P-MAG side of the ignition (if not running dual P-MAGs), and gradually
slow the engine toward idle. Note the speed where the engine quits (if
at all). If this speed is comfortably less than your in-flight idle speed,
you should be covered. If not, simply note the operating limitation so you'll
be prepared if the actual emergency is ever encountered. Most, of the people
we talk to have an in-flight idle of roughly 1000 rpm, or more.
To answer the question: Yes, if a prop windmills fast enough, it could drive the
P-MAG alternator and allow the ignition to fire.
I hope that helps.
Kindest Regards,
Brad Dement
E-MAG Ignitions
817 448 0555
-----Original Message-----
From: Joe & Jan Connell [mailto:jconnell(at)rconnect.com]
Subject: A question about P-Mags when engine is windmilling
Hi Brad,
A question was posed on the AeroElectric -list this morning that
is of interest. It deals with the minimum RPM neccessary for a
P-Mag to fire plugs.
Regards,
Joe Connell
From: "Jim Jewell" <jjewell(at)telus.net>
Subject: Re: AeroElectric-List: PMags and RPM
I think this sounds like a good question to ask the people that make the
PMmags.
Does someone that plays a principle role in the company monitor the list?
Jim in Kelowna
----- Original Message -----
From: <owner-aeroelectric-list-server(at)matronics.com>
Subject: AeroElectric-List: PMags and RPM
>
> Listers - PMags appear to be a good way to go safety wise as it renders
> (in
> principle) ignition independent of the electrical system. But this only
> happens if RPM is high enough.
>
> In case of the unlikely scenario that the electrical system should die and
> the RPM should fall below PMag's self sustaining level, would wind milling
> by diving bring the engine RPM up sufficiently, thereby restoring engine
> power?
>
> A similar scenario would occur as one is on short final with engine at 800
> RPM. If the electrical system is down, are we in a situation whereby the
> PMag could stop generating its own electricity, thereby committing the
> flight to a definitive landing no matter what, i.e. no go around
> possibility?
>
> Michle
> RV8 - Wings
________________________________________________________________________________
| From: | "Chris Horsten" <airplanes(at)sympatico.ca> |
Hi Fellows,
Not sure how long it takes for messages to turn around on this list, but
hopefully quick.
I have a buddy ferrying a homebuilt and he is stuck partway there with an
electrical problem (Saturday afternoon). Everything was fine until they took
off from a fuel stop. The power went out so they landed to trouble shoot.
They had a hand held radio and gps although it seems that both of these quit
too. They elected to continue with the handhelds but once in the air they
got tremendous static from the radio making it unusable. The built-in stuff
not working at all I gather.
Any ideas? The engine is a Continental O-300 with a generator, pretty
standard setup otherwise - master, voltage regulator, etc.
The pilot is going to call me later tonight so he can fix in the am before
finishing the trip.
Thanks for any help
Chris
________________________________________________________________________________
| From: | Earl_Schroeder <Earl_Schroeder(at)juno.com> |
Hi Chris,
I take it from your email adr that the ferry pilot isn't stuck anywhere
near S Indiana?? If in fact he is, I'll be glad to offer any assistance
I could provide.
If the GPS and hand held com both quit along with the afct electrics,
hmmmm, sounds like something from outer space.. ;-)
Earl
Chris Horsten wrote:
>
>Hi Fellows,
>
>Not sure how long it takes for messages to turn around on this list, but
>hopefully quick.
>
>I have a buddy ferrying a homebuilt and he is stuck partway there with an
>electrical problem (Saturday afternoon). Everything was fine until they took
>off from a fuel stop. The power went out so they landed to trouble shoot.
>They had a hand held radio and gps although it seems that both of these quit
>too. They elected to continue with the handhelds but once in the air they
>got tremendous static from the radio making it unusable. The built-in stuff
>not working at all I gather.
>
>Any ideas? The engine is a Continental O-300 with a generator, pretty
>standard setup otherwise - master, voltage regulator, etc.
>
>The pilot is going to call me later tonight so he can fix in the am before
>finishing the trip.
>
>Thanks for any help
>
>Chris
>
>
>
>
________________________________________________________________________________
| From: | "Chris Horsten" <airplanes(at)sympatico.ca> |
Hi Earl,
Thanks for the kind offer. They are in McCook Nebraska.
Outerspace was exactly what I said - either that or the military trying out
their latest jamming hardware. Well it seems the handhelds were connected to
ships power at the time (an Ipac running Anywhere map and a radio).
I have spoken to another builder and he suggested
A) the brushes on the generator
B) The master solenoid
C) the Voltage generator.
Whatever it is, even with the generator off line there is some serious
interference being generated that is making even the handheld radio on
battery power unusable. Could the generator still make noise if it was off
line?
Chris
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of
Earl_Schroeder
Subject: Re: AeroElectric-List: Help!
-->
Hi Chris,
I take it from your email adr that the ferry pilot isn't stuck anywhere near
S Indiana?? If in fact he is, I'll be glad to offer any assistance I could
provide.
If the GPS and hand held com both quit along with the afct electrics, hmmmm,
sounds like something from outer space.. ;-) Earl
Chris Horsten wrote:
>-->
>
>Hi Fellows,
>
>Not sure how long it takes for messages to turn around on this list,
>but hopefully quick.
>
>I have a buddy ferrying a homebuilt and he is stuck partway there with
>an electrical problem (Saturday afternoon). Everything was fine until
>they took off from a fuel stop. The power went out so they landed to
trouble shoot.
>They had a hand held radio and gps although it seems that both of these
>quit too. They elected to continue with the handhelds but once in the
>air they got tremendous static from the radio making it unusable. The
>built-in stuff not working at all I gather.
>
>Any ideas? The engine is a Continental O-300 with a generator, pretty
>standard setup otherwise - master, voltage regulator, etc.
>
>The pilot is going to call me later tonight so he can fix in the am
>before finishing the trip.
>
>Thanks for any help
>
>Chris
>
>
>
>
________________________________________________________________________________
| From: | "Jim Stone" <jsto1(at)tampabay.rr.com> |
I would consider taking the belt off the generator, starting the engine
on the ground, and seeing if the noise on the radio goes away. This
might indicate that the generator is arcing and creating a broad
spectrum of noise which could jam both the radio and GRS.
Good Luck,
Jim Stone
Jabiru J450
Clearwater FL.
________________________________________________________________________________
| From: | "Chris Horsten" <airplanes(at)sympatico.ca> |
Thanks Jim,
Unfortunately the generator on the O-300 is "plugged" into the back of the
engine, i.e. no belt. However the brushes are apparently easy to change.
I have further info on the problem and there is power. Com can receive but
then reverts to major static. Also, ident light on Transponder is on solid.
I'm wondering now if it is a regulator gone bad resulting in a voltage spike
which may now have fried something's. The IPAC is working fine - not kaput
as previously though.
Funny that the noise remains even after the generator is taken off line. I
don't know if the voltage regulator can still produce noise if the
generator is off line and the VR is toast?
Chris
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Jim Stone
Subject: RE: AeroElectric-List: Help!
-->
I would consider taking the belt off the generator, starting the engine on
the ground, and seeing if the noise on the radio goes away. This might
indicate that the generator is arcing and creating a broad spectrum of noise
which could jam both the radio and GRS.
Good Luck,
Jim Stone
Jabiru J450
Clearwater FL.
________________________________________________________________________________
| From: | "Mark Taylor" <mtaylo17(at)msn.com> |
Listers,
I have a relay with hooks on it as supplied with my FADEC Cabin harness kit.
Pictures available at http://home.comcast.net/~mtaylo17/RV7/fadec.htm#Latest
Does anybody know how I'm supposed to make a connection to this thing? Right
now, I'm assuming I twist a loop in the wire, hook it on and solder it.
Seems to go against convention of not soldering stuff if you can help it.
Thanks,
Mark Taylor
www.4sierratango.com
________________________________________________________________________________
| From: | "Richard E. Tasker" <retasker(at)optonline.net> |
Actually, it doesn't go against the convention of not soldering if you
can help it - in this case you cannot help it :-) !
Seriously, I don't see any other way you could connect to this relay.
There is nothing wrong with a good solder joint. The main thing you
will have to do is make sure that you provide good strain relief for the
wires. Some shrink sleeving and a place to tie the cable down to
something solid should give you a good installation.
Dick Tasker
Mark Taylor wrote:
>
>Listers,
>
>I have a relay with hooks on it as supplied with my FADEC Cabin harness kit.
>Pictures available at http://home.comcast.net/~mtaylo17/RV7/fadec.htm#Latest
>
>Does anybody know how I'm supposed to make a connection to this thing? Right
>now, I'm assuming I twist a loop in the wire, hook it on and solder it.
>
>Seems to go against convention of not soldering stuff if you can help it.
>
>Thanks,
>
>Mark Taylor
>www.4sierratango.com
>
----
Please Note:
No trees were destroyed in the sending of this message. We do concede, however,
that a significant number of electrons may have been temporarily inconvenienced.
----
________________________________________________________________________________
| From: | mprather <mprather(at)spro.net> |
Random questions and comments:
If it were the brushes, I would guess that there would be some warning
symptoms. I have had alternator brushes go bad before, and normally,
the alternator light starts to flash occasionally, or just at start up.
Finally it gets bad enough that the battery is not getting charged, and
then is dead.
Is this airplane new, or new to your friend? I am wondering about pre
existing, but undisclosed problems, like maybe the charging system never
actually worked, but the seller sent them on their way with a charged
battery. Now maybe it's low?
Does the engine crank okay with battery power?
Do the stranded folks have any diagnostic instrumentation at their
disposal? It would be helpful if they either have a panel mounted
volt/charging meter, or even better, if they have access to a
multimeter. Check the battery voltage with everything turned off, then
again with the engine running.
My Narco transponder light stays on solid for the first few minutes of
operation (I assume during warmup). I wonder if they have left the txp
on long enough to warm up.
I also wonder if bus voltage is so low that the com radio is having
problems operating.
I am not a generator expert.. I sort of doubt the generator has the
capability to raise the bus voltage high enough to damage anything, but
I could be wrong.
If the system is actually pretty standard, find a mech to take a look at it.
Is the airplane a Tailwind (random shot - I couldn't think of any other
OBAM aircraft that have O-300's)?
Good luck. Keep us posted..
Regards,
Matt-
Chris Horsten wrote:
>
>Thanks Jim,
>
>Unfortunately the generator on the O-300 is "plugged" into the back of the
>engine, i.e. no belt. However the brushes are apparently easy to change.
>
>I have further info on the problem and there is power. Com can receive but
>then reverts to major static. Also, ident light on Transponder is on solid.
>I'm wondering now if it is a regulator gone bad resulting in a voltage spike
>which may now have fried something's. The IPAC is working fine - not kaput
>as previously though.
>
>Funny that the noise remains even after the generator is taken off line. I
>don't know if the voltage regulator can still produce noise if the
>generator is off line and the VR is toast?
>
>Chris
>
>
>-----Original Message-----
>From: owner-aeroelectric-list-server(at)matronics.com
>[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Jim Stone
>To: aeroelectric-list(at)matronics.com
>Subject: RE: AeroElectric-List: Help!
>
>-->
>
>I would consider taking the belt off the generator, starting the engine on
>the ground, and seeing if the noise on the radio goes away. This might
>indicate that the generator is arcing and creating a broad spectrum of noise
>which could jam both the radio and GRS.
>
>Good Luck,
>Jim Stone
>Jabiru J450
>Clearwater FL.
>
>
>
>
________________________________________________________________________________
| From: | "Chris Horsten" <airplanes(at)sympatico.ca> |
Hi Matt,
Thanks for this hints
It's a Zenith CH-250. A further report from the ferry pilot reveals that
there is power. Radio is good during a message received, but reverts to
static once it ends. I will advise them re the TX as they probably don't
know that (I didn't). The aircraft was running perfect up until now. No
known issues. We did switch out the encoder about a week ago because the
last one seemed bad.
Re voltage being low I don't think this is the problem. Something is
generating some noise, because even the hand held is acting up and it is
operating on its own power. Engine is running fine and was started up at
least twice for a circuit after the problem surfaced. They are handing off
to a mechanic this am I believe.
Other possible sources: Master relay? Noise filter (capacitor)? Voltage
regulator?
Chris
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of mprather
Subject: Re: AeroElectric-List: Help!
Random questions and comments:
If it were the brushes, I would guess that there would be some warning
symptoms. I have had alternator brushes go bad before, and normally, the
alternator light starts to flash occasionally, or just at start up.
Finally it gets bad enough that the battery is not getting charged, and then
is dead.
Is this airplane new, or new to your friend? I am wondering about pre
existing, but undisclosed problems, like maybe the charging system never
actually worked, but the seller sent them on their way with a charged
battery. Now maybe it's low?
Does the engine crank okay with battery power?
Do the stranded folks have any diagnostic instrumentation at their disposal?
It would be helpful if they either have a panel mounted volt/charging meter,
or even better, if they have access to a multimeter. Check the battery
voltage with everything turned off, then again with the engine running.
My Narco transponder light stays on solid for the first few minutes of
operation (I assume during warmup). I wonder if they have left the txp on
long enough to warm up.
I also wonder if bus voltage is so low that the com radio is having problems
operating.
I am not a generator expert.. I sort of doubt the generator has the
capability to raise the bus voltage high enough to damage anything, but I
could be wrong.
If the system is actually pretty standard, find a mech to take a look at it.
Is the airplane a Tailwind (random shot - I couldn't think of any other OBAM
aircraft that have O-300's)?
Good luck. Keep us posted..
Regards,
Matt-
________________________________________________________________________________
| From: | "Eric M. Jones" <emjones(at)charter.net> |
| Subject: | RE: OVP etc - Bottom Line |
Paul Messinger forced all this to condense and the more I look at it the
more I like it.
My opinion only---and I have a lot of them. I am building a Glastar and as
of this date, here's what I believe is going into it----
1) I would buy a new or expertly rebuilt internally regulated Nippondenso
55A (or so).
2) I would use a fusible link as the B+ lead from the alternator and hang
off it 6 X 5kW 18V unidirectional Transorbs (and one or two bi-directionals
around, too). It would be fine and perhaps preferable to distribute these
Transorbs, the reason being that a lightning strike might well do less
damage is the transorbs are generally sprinkled instead of grouped.
3) Battery disconnect contactor would be eliminated but if the FAA wants it
then I would design this as a pull-to-disconnect mechanical switch at the
battery terminals (from car racing products). Use only in a real crash
emergency and maybe a half-way-decent anti-theft device.
All the details of busses and batteries need to be worked out. But this is a
core part. No crowbar, no OVP, no alternator contactor, no battery
contactor, no external regulator, no field breaker, no load dump concerns,
maximum reliability, minimum cost and weight.
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones(at)charter.net
The whole difference between construction and creation is exactly this:
That a thing constructed can only be loved after it is constructed;
but a thing created is loved before it exists.
- Charles Dickens
________________________________________________________________________________
| From: | "Paul Messinger" <paulm(at)olypen.com> |
| Subject: | Re: OVP etc - do we have a bottom line? |
I am sorry that the exchanges are so long and confusing (I am getting
confused myself).
Much of the debate is regarding worst case design and the design approach of
the OVP that can false trigger.
Then there is the current and the related CB ratings.
Also there is the potential of alternator damage in the case of a false
trip.
Lets go back and see where we are right now.
The CB max no damage current rating is a personal concern to some and not a
big deal IF you have a real event as the alternator has failed. replacing
the CB may or may not be needed. A purest will replace it most will simply
press on by resetting. My objection is it does overstress the CB and a good
design of OVP would limit the current so there would be no question.
The high current of hundreds of amps is a concern in some cases. It depends
on if you have steel tubes in the cockpit (many of us do) and even if not
the modern avionics sometimes include sensitive magnetometers that can be
overloaded with hi currents nearby (near by can be more than 12" and still
be too close. Finally if your engine depends on the 12 V bus to be above
some voltage to run there is a potential case when the OVP module trips.
this depends on the specific electronics. I have a documented case of
certificated aircraft having major compass errors accumulating over time
with currents around 50 amps max passing 18" away from the compass so it can
be a concern (The mandatory service bulletin to correct this problem will
be soon posted here for all to see).
If you have a RV with Van's alternator add the recommended Transorbs and
consider using Erics OVP approach. If you have the Aeroelectric OVP any
false trip is unlikely to be a problem to the alternator with the added
Transorbs.
There is little probability of problems with the B & C conversion using the
LR-3 regulator but adding "B" 'lead transorbs are recommended by both Eric
and myself on all alternators.
If you have a Glastar or other aircraft with a steel tube inner or outer
cabin structure I would NOT use Bob's OVP module simply due to the poor
effects of HI currents in the cabin. IE careful wiring and transient
currents in the 50 amp or above might be hazardous to your flight
instruments and as a minimum a compass accuracy check on an annual basis is
recommended.
In conclusion;
There is simply no one size fits all that is safe to use. Most of the
builders are safe with the externally regulated LR-3 setup. some will be
unsafe with the use of Bob's OVP module and many are in the middle.
However remember any who want to use the emergency mode of "No battery" need
to know that both the LR-3 and the OVP module have a 100% chance of tripping
the alternator off line with no battery and the often suggested addition of
a 25,000 mfd capacitor to "stabilize the alternator regulator is by test not
going to prevent false triggering of these devices from such simple things
as turning off landing lights or strobes or recognition lights if the
alternator is lightly loaded.
No battery operation is my opinion a very important emergency mode of
operation.
Here is what Bob has recently stated on this subject "but the question of
no-battery operation has never been addressed nor recommended in any of my
writings"
I agree that none of his suggested schematic designs allow this mode simply
because they all include a LR-3 or OVP module that triggers with a load sump
(that Bob requires the battery to clamp). No battery, no clamp, first event
and alternator trips off line and no electrical power.
But this is a different discussion.
Sorry but as there is no one solution proposed todate we have no simple
reply.
Paul
----- Original Message -----
From: "Vincent Welch" <welchvincent(at)hotmail.com>
Subject: RE: AeroElectric-List: OVP etc - do we have a bottom line?
>
>
> A M E N ! ! !
>
>
>>From: Richard Riley <Richard(at)RILEY.NET>
>>Reply-To: aeroelectric-list(at)matronics.com
>>To: aeroelectric-list(at)matronics.com
>>Subject: AeroElectric-List: OVP etc - do we have a bottom line?
>>Date: Fri, 01 Apr 2005 07:47:28 -0800
>>
>>
>>I've now spent much of the night trying to read and understand all the
>>objections to and defences of the crowbar OVP system.
>>
>>I still have no idea who's right. I just have a migraine.
>>
>>If I'm willing to spend enough money, can I build a system that satisfies
>>all the critics? For example, many of the crowbar posts involve
>>internally
>>regulated alternators. If I'm using a B&C 60 amp alternator, an LR3, and
>>SD8 and 2 batteries, am I still in danger of frying $50k worth of avionics
>>because I blinked wrong?
>>
>>Please understand, I am willing to spend whatever it takes to make this
>>problem (if it is a problem) go away. I don't want the "best" solution, I
>>want all the solutions that are worthwhile and applicable. I'm not going
>>to worry about an extra $100 for a transorb, I want belt and suspenders
>>and
>>nail gun and epoxy. Is that possible? Or are the approaches being
>>described mutually incompatible?
>>
>>
>
>
>
________________________________________________________________________________
| Subject: | Looking for a B&C oil pressure switch pinout... |
| From: | "Marcos Della" <mdella(at)cstone.com> |
Ok, I got one of the three connector switches. Normally I've seen the
connections
Marked as C, NC, and NO. On this one they are marked P, S, and I... So.
Which ones
Are which? w/o pressure, P and S are shorted... But I don't know which
one of them
Is the "common" lead...
Marcos
________________________________________________________________________________
| From: | "Paul Messinger" <paulm(at)olypen.com> |
After a long and frequent (cross country WA to MA) telecoms etc etc. WE
(Eric and I, partners in the Load dump testing of last year) have agreed
that the current approach of multiple busses, emergency (essential) busses,
lots of configurations, etc, etc, is simply the wrong approach. The more
complex the design the more likely of failure and or improper pilot usage.
Having a "after failure of the alternator" multipart reconfiguration check
list is not a good idea in my opinion (as I recall Bob's design needs up to
6 steps to reconfigure for emergency ops).
What started as a simple design years ago seems to have been patched and
repatched into a multi bus multi battery multi alternator complex mess of
wiring etc than even experts have trouble understanding. Its time to start
with a fresh blank page and consider faults with regard to probably in a
more reasonable light. "Keep It Simple Stupid" (KISS) usually works if given
a chance. However unlikely a fault is its been fixed by adding circuits
regardless of how complex the addition might be and how that addition might
add more failures than were prevented based on probabilities.
What is wrong in considering a design that is single fault tolerant?
Why mess things up with high complexity that supports dual and triple fault
tolerance??
Why worry about faults that are as likely as prop bolt failures?
The old (and current) dual mag acft engines are single fault tolerant. Most
of us feel any well designed electrical system is more reliable than a mag.
The fuel system typically either needs no pump or the engine pump is backed
up with an electrical aux pump. Again single fault tolerant has served us
well for over 50 years.
One battery and one alternator is an electrical system that can provide
power if either one fails.
If the alternator fails, a properly maintained battery will provide power to
a safe airport (as a minimum). I maintain we need a "battery fuel gauge" to
be sure we are managing the electrical loads. At a minimum, a battery
current monitor to really see the current load (assumptions here are not a
good idea). The battery fuel gauge I refer to is a new product I am working
on that does not rely on the pilot figuring current vs. time etc. It
provides the time remaining based on past and current load. Change the load
and the time remaining is updated to the new load.
For an all electric engine like an automotive conversion that needs 10-20
amps to operate a single or redundant IGN and FUEL system you can add single
fault tolerance in that system if you feel that the OEM computer/fuel pump
needs backup. The single electrical system will supply one or both engine
systems.
Some feel the stock system is reliable enough. Personally I have not seen or
heard of a stock system failing (once it was properly converted). ALL the
auto engine conversion failures I have looked at were support system
failures (not counting problems with incomplete or improper conversion to
meet the needs of the computer in an aircraft application). Consider the
automotive engine failure rate, its extremely low due to the
engine/electrical systems failure, one per million hours has been quoted by
one person that I greatly respect.
For this to work we need to disregard faults so unlikely as never happening.
Main power wiring is easy to protect such that a short is simply not
something to worry about (like Bob's prop bolts or wing spar bolts etc).
There is a lot of discussion about the case of an alternator not just
failing high but failing in a mode where the output is huge and totally
uncontrolled where speculation of currents of several timed ratings and
voltages of hundreds of amps are discussed. In fact the known failures of
this rare of the rarest failures is far lower than prop bolts which have
documented failures in experimental props (including resulting fatalities).
If we discard this failure mode in the alternator, as we have above
discarded a power system short, we can get a very simple system designed
that saves weight and is easy to build and use. I am not saying that things
like the avionics bus should not be considered for those who feel the
usefulness and convenience of a single switch on / off for avionics, just
the single main power bus consisting of a battery and an alternator
connected with heavy power wire. Individual disconnects and OVP and etc are
add on's to this basic bus.
Eric and I are going to pursue this off line considering that remotely
possible failures are normally not a concern.
Eric is the main driver of this and I have jumped the gun with this post but
he is likely to post also soon and together you can see our approach which
is KISS as a design rule.
Eric has been the trigger for my exploring new designs and I have found that
even 10 years ago we (the OBAM community) could have benefited with the
application of technology taken from the auto industry requirements.
Its sad we all have been moving backwards because no one failed to look at
automotive products with respect to aircraft. Better, lower cost, lighter,
higher tolerance for transients, and wider temperature ranges etc etc.
Simply better in all respects, if properly integrated in to a fresh design
approach.
I simply am not willing to do it the way its been done for 40 years
regardless of how well that approach worked when there is a better approach
available that is proven to be reliable in practice.
Paul
Yes I will get around to more replies to previous posts by Bob and others
soon.
----- Original Message -----
From: "Eric M. Jones" <emjones(at)charter.net>
Subject: AeroElectric-List: RE: OVP etc - Bottom Line
>
>
> Paul Messinger forced all this to condense and the more I look at it the
> more I like it.
>
> My opinion only---and I have a lot of them. I am building a Glastar and as
> of this date, here's what I believe is going into it----
>
> 1) I would buy a new or expertly rebuilt internally regulated Nippondenso
> 55A (or so).
>
> 2) I would use a fusible link as the B+ lead from the alternator and hang
> off it 6 X 5kW 18V unidirectional Transorbs (and one or two
> bi-directionals
> around, too). It would be fine and perhaps preferable to distribute these
> Transorbs, the reason being that a lightning strike might well do less
> damage is the transorbs are generally sprinkled instead of grouped.
>
> 3) Battery disconnect contactor would be eliminated but if the FAA wants
> it
> then I would design this as a pull-to-disconnect mechanical switch at the
> battery terminals (from car racing products). Use only in a real crash
> emergency and maybe a half-way-decent anti-theft device.
>
> All the details of busses and batteries need to be worked out. But this is
> a
> core part. No crowbar, no OVP, no alternator contactor, no battery
> contactor, no external regulator, no field breaker, no load dump concerns,
> maximum reliability, minimum cost and weight.
>
> Regards,
> Eric M. Jones
> www.PerihelionDesign.com
> 113 Brentwood Drive
> Southbridge MA 01550-2705
> Phone (508) 764-2072
> Email: emjones(at)charter.net
>
>
> The whole difference between construction and creation is exactly this:
> That a thing constructed can only be loved after it is constructed;
> but a thing created is loved before it exists.
> - Charles Dickens
>
>
>
________________________________________________________________________________
| From: | "simon miles" <simon.miles(at)skynet.be> |
| Subject: | Please help!! Re OVP etc - do we have a bottom line? |
0.51 PLING_QUERY Subject has exclamation mark and question mark
Will somebody please tell me how all this incredible discussion helps me
build a safer aeroplane?
I am of the impression that ignoring everyone's advice will leave me no
worse off. It seems, for example, Cessna do one thing, Vans recommend
something else, then Bob recommends another solution and Paul recommends yet
another. The supplier of my Europa kit offers yet another solution. And all
the time I'm looking for evidence that aeroplanes are plunging from the
skies (or even diverting to nearby airports) because of the faults these
solutions are trying to address.
I have wired my aeroplane according to Bob's advice and have been very
impressed with the results (and the understanding I have gained along the
way). I fly daytime VFR and I don't see why I need any other OV protection
other than Bob's OV crowbar.
If I should know more, please tell me in terms that are easily understood
(!). The arcane nature of the exchanges that have gone before means that
very little information is transferred - especially for those that don't
know the difference between a transorb and a transistor...
Simon Miles
--- Original Message -----
From: "Paul Messinger" <paulm(at)olypen.com>
Subject: Re: AeroElectric-List: OVP etc - do we have a bottom line?
>
>
> I am sorry that the exchanges are so long and confusing (I am getting
> confused myself).
> Sorry but as there is no one solution proposed todate we have no simple
> reply.
>
> Paul
________________________________________________________________________________
| From: | "Fergus Kyle" <VE3LVO(at)rac.ca> |
| Subject: | Making REAL world sense, etc. |
I'm happy the way it is!
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
So am I!
Don't censure my reading............
Cheers, Ferg Kyle
similarly stricken
________________________________________________________________________________
| From: | "Brian Kraut" <brian.kraut(at)engalt.com> |
| Subject: | Zeftronics transistor |
I have a Zeftronics R15100 voltage regulator that is blown because the
previous owner of the plane used a shielded wire on the alternator without
the shield insulated and it shorted to the field stud on the alternator.
The TO-220 output transistor is toasted and I can't read the complete part
number on it. It is a TIP1 something. If I had to take a wild ass guess I
would say a TIP120 is the most likely candidate, but I want to be sure.
Does anyone know for sure or know where I can get a schematic?
Brian Kraut
Engineering Alternatives, Inc.
www.engalt.com
________________________________________________________________________________
| From: | Christopher Stone <rv8iator(at)earthlink.net> |
| Subject: | OVP, grounds, resistive loads |
Bob...
Thanks for a great 'lectric seminar in Independence, OR! You are more then patient
with answering my many questions. As with any educational endevour it has
made me question some assumptions and added to a better understanding of others.
Again... Thank you!
As I get deeper into the wiring of the first of two RV 8s the discussions of OVP
here seem to raise more questions then answers.
1. I am using the Fig. Z-13/8 as a template with the addition of an avionics master
in between the main bus and endurance bus. A Nippondenso 40 Amp alt. with
internal regulator and a three terminal alternator disconnect contactor. A
B&C OVM-14. The OVM-14 sense lead is connected directly to the master sw (faston
crimped onto the uncut yellow lead). The black lead is butt spliced to a
six foot AWG 20 ground that connects to the forest of fastons bolted to the firewall
and connected to the bat neg. by 8 ft of AWG 2 welding cable. After reading
your white paper on OVP wire resistance appears to be a variable that may
add to the current spike across the 5A breaker. Is this acceptable?
2. I am using a single point ground for all grounds per above description. Z-13
shows a firewall ground, instrument ground and avionics ground. I don't see
any reason not to combine all these to a single point. Am I missing something?
3. Pure resistive loads (heater elements)should not be a source of electrical
noise. That said, I am locally grounding the pitot heat and seat heaters. Again,
am I missing anything here?
4. The wire feeding the main bus is shown unprotected. In my ship this is four
feet of AWG 6 that goes from the bat side of the starter contactor to the main
fuse block. I realize that turning off the master turns this off, but a
short to ground along this wire run could be disastrous! Do I need to be concerned?
Per the ongoing discussions here by Paul, Eric et al one valid issue raised is
system reliability by virtue of simplicity. The simplicity of an internally regulated
alternator vs an externally regulated alternator with the additional
wiring and connections required to connect the external voltage regulator would
seem to favor the internally regulated "one piece" charging system.
At this point I am going to use the crowbar OVP due to it's simplicity albeit the
brute force approach.
Chris Stone
Newberg, OR
A pair of RV-8s
________________________________________________________________________________
| From: | "Dan O'Brien" <limadelta(at)gmail.com> |
| Subject: | Re: Fresh approach |
Paul,
Your post has me confused. You say:
>What is wrong in considering a design that is single fault tolerant?
That's precisely what I've been reading about on this list for years.
It is one of the main messages of the chapter in the Connection on
Electrical System Reliability.
You say:
>Why mess things up with high complexity that supports dual and triple fault
>tolerance??
I don't remember dual and triple fault tolerances being pushed hard on
this list or in the Connection. In fact, I recall numerous occasions
on this list and in the Connection in which people pointed out that
the probability of two system failures in any one flight is extremely
remote. This is why the focus is on taking steps so that no single
failure wreaks havoc. If the probability of failure A is one in a
thousand and the probability of failure B is one in a thousand, and if
the two events are independent, then the probability that both fail is
one in a million (= one one-thousandth times one-one-thousandth).
(The analysis is different if the events are correlated, but we know
how to handle that.) The FAA uses this idea to justify allowing twin
jets to fly a long distance over water. Isn't this precisely the
philosophy implicit in most of the discourse about failure tolerance
on this list?
>There is a lot of discussion about the case of an alternator not just
>failing high but failing in a mode where the output is huge and totally
>uncontrolled where speculation of currents of several timed ratings and
>voltages of hundreds of amps are discussed. In fact the known failures of
>this rare of the rarest failures is far lower than prop bolts which have
>documented failures in experimental props (including resulting fatalities).
>If we discard this failure mode in the alternator, as we have above
>discarded a power system short, we can get a very simple system designed
>that saves weight and is easy to build and use.
I thought over voltage conditions were typically caused by failed
regulators rather than failed alternators. Are prop bolt failures
more frequent that failed regulators? Maybe so...I'm asking. Is a
failed prop bolt more likely to ruin your day than a failed regulator
in the absence of OVP? I think I have five or six prop bolts. With a
single alternator single battery system, I would have one regulator.
I'm certainly no expert, and I haven't surveyed the accident reports,
but I guess I'm skeptical.
I'm even more confused about the notion of ignoring runaway
alternators (failed regulators) in light of the OVP debate, where you
seem worried about battery failure as an important reason for harmful
load dumps. Is it more likely for a battery to fail than an
alternator or regulator to fail?
Just trying to understand.
Dan
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | OVP etc - do we have a bottom line? |
>
>Will somebody please tell me how all this incredible discussion helps me
>build a safer aeroplane?
Not at all if you're not engaged . . .
>I am of the impression that ignoring everyone's advice will leave me no
>worse off. It seems, for example, Cessna do one thing, Vans recommend
>something else, then Bob recommends another solution and Paul recommends yet
>another. The supplier of my Europa kit offers yet another solution. And all
>the time I'm looking for evidence that aeroplanes are plunging from the
>skies (or even diverting to nearby airports) because of the faults these
>solutions are trying to address.
You're right. The vast majority of airplanes flying today were
architectured with features that conform to nothing that Paul
nor I have discussed.
>I have wired my aeroplane according to Bob's advice and have been very
>impressed with the results (and the understanding I have gained along the
>way). I fly daytime VFR and I don't see why I need any other OV protection
>other than Bob's OV crowbar.
Don't think you do, thousands of systems are flying with that configuration,
none have reported adverse effects of the crowbar system design but many
have reported being grateful that it was there and did the job it was
designed to do when the regulator went bad.
>If I should know more, please tell me in terms that are easily understood
>(!). The arcane nature of the exchanges that have gone before means that
>very little information is transferred - especially for those that don't
>know the difference between a transorb and a transistor...
Again, if you're not engaged, then ignore it all. If you've been
persuaded by some words you've read to make some changes and wont
quit worrying about it until the changes are made, then make the
changes. Push-comes-to-shove, wire it like a Cessna . . . there's
been a whole pot full of those flown for decades and perhaps we
can Sunday morning quarterback those systems and suggest modifications
but it's the devil we all know. Don't snuggle up next to a new one
unless you KNOW it as well.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Fresh approach |
>
>After a long and frequent (cross country WA to MA) telecoms etc etc. WE
>(Eric and I, partners in the Load dump testing of last year) have agreed
>that the current approach of multiple busses, emergency (essential) busses,
>lots of configurations, etc, etc, is simply the wrong approach.
For who, on what kind of airplane and for what mission. For example,
if I were building an airplane today, I'd use Z-13 with dual P-mags.
Please explain to me how any of those busses are excessively redundant
or complex?
>The more
>complex the design the more likely of failure and or improper pilot usage.
>Having a "after failure of the alternator" multipart reconfiguration check
>list is not a good idea in my opinion (as I recall Bob's design needs up to
>6 steps to reconfigure for emergency ops).
Absolute BS Paul. Describe your perceived emergency checklist for
emergency ops on ANY system described in the 'Connection . . . no,
let's limit it to Z-13. If a low voltage light comes on, what is
your perception of pilot response that take more than three steps?
>What started as a simple design years ago seems to have been patched and
>repatched into a multi bus multi battery multi alternator complex mess of
>wiring etc than even experts have trouble understanding.
It's happened in some airplanes. I'll see if I can publish power
distribution
diagrams for a Beechjet or Hawker . . . Pilots go to schools for weeks to
marginally understand those systems. Z-14 is a small fraction of the
complexity
of those airplanes and is applicable to less than 1% of the OBAM aircraft
fleet. Things get much simpler from there.
It's all explained in Chapter 17 . . . quote me the paragraph and
page that has any expert confused.
> Its time to start
>with a fresh blank page and consider faults with regard to probably in a
>more reasonable light. "Keep It Simple Stupid" (KISS) usually works if given
>a chance. However unlikely a fault is its been fixed by adding circuits
>regardless of how complex the addition might be and how that addition might
>add more failures than were prevented based on probabilities.
>
>What is wrong in considering a design that is single fault tolerant?
None.
>Why mess things up with high complexity that supports dual and triple fault
>tolerance??
When have I ever spoken to a failure chain beyond one event?
Please publish the architecture you propose. Get it to me in the
next week and it will be figure Z-20 in the book. I've been trying
to built a sense of how any and all systems work by studying and describing
functionality of the various components so that their operation can
be predicted when assembled into a system.
You pushed aside a DEMONSTRATED current limit of under 260 amps for
a crowbar event and insisted that events in the 400A to 700A range
exist. Tell me how to duplicate your measurement or drop it.
You make statements that ARE YET to be described in any repeatable
experiment yet you push aside my fully described and published experiment
by claiming that I have made some conclusion based on a single test which
represents no type of engineering you respect. This was in spite of the
fact that no conclusion was made. I did the work, gathered the data,
hypothesized a 250A max limit (installed systems run much lower) and
you have yet to tell me where that experiments was bad . . . respectable
or otherwise.
>Why worry about faults that are as likely as prop bolt failures?
No reason what so ever. Show me the schematic.
>I simply am not willing to do it the way its been done for 40 years
>regardless of how well that approach worked when there is a better approach
>available that is proven to be reliable in practice.
Virtually nothing published in the Connection is "the way
we've been doing it for 40 years" except that we build those
systems from the same collection of basic components like
batteries, alternators, contactors, etc. Fielding your
pejorative platitudes is getting wearisome.
Show us the numbers . . . show us the schematics . . . explain the
plan-A, plan-B, plan-C checklists. To date my friend I
I've seen nothing that I can address from the perspective
of a logical critical review. I've explained everything I've
done and demonstrated underlying fundamentals in hopes of building
a foundation for logical critical review. The feedback in
received from you has only generated a need to address your concerns
by going to the manufacturers and other spec sources. My job keeps
getting bigger while we are yet to receive benefit of any definitive
description on your proposal for next evolutionary step in aviation
electrical systems.
>Yes I will get around to more replies to previous posts by Bob and others
>soon.
Forget the rest of it. I've got weeks of research to do into
the breaker rating issue. I'm going to be really busy fixing a couple
of "fix it or keep it" airplanes and there are folks on the list including
me that want to know "Where's the beef?" Autocad drawings are best,
.pdf's are most acceptable but I'll work with crayon on toilet paper
if necessary. If you're offering the next greatest thing, let's get
it out there for folks to exploit. I've hidden nothing, you've
revealed nothing.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: OVP etc - do we have a bottom line? |
>
>I am sorry that the exchanges are so long and confusing (I am getting
>confused myself).
>
>Much of the debate is regarding worst case design and the design approach of
>the OVP that can false trigger.
>
>Then there is the current and the related CB ratings.
>
>Also there is the potential of alternator damage in the case of a false
>trip.
>
>Lets go back and see where we are right now.
>
>The CB max no damage current rating is a personal concern to some and not a
>big deal IF you have a real event as the alternator has failed. replacing
>the CB may or may not be needed. A purest will replace it most will simply
>press on by resetting. My objection is it does overstress the CB and a good
>design of OVP would limit the current so there would be no question.
>
>The high current of hundreds of amps is a concern in some cases. It depends
>on if you have steel tubes in the cockpit (many of us do) and even if not
>the modern avionics sometimes include sensitive magnetometers that can be
>overloaded with hi currents nearby (near by can be more than 12" and still
>be too close. Finally if your engine depends on the 12 V bus to be above
>some voltage to run there is a potential case when the OVP module trips.
>this depends on the specific electronics. I have a documented case of
>certificated aircraft having major compass errors accumulating over time
>with currents around 50 amps max passing 18" away from the compass so it can
>be a concern (The mandatory service bulletin to correct this problem will
>be soon posted here for all to see).
>
>If you have a RV with Van's alternator add the recommended Transorbs and
>consider using Erics OVP approach. If you have the Aeroelectric OVP any
>false trip is unlikely to be a problem to the alternator with the added
>Transorbs.
>
>There is little probability of problems with the B & C conversion using the
>LR-3 regulator but adding "B" 'lead transorbs are recommended by both Eric
>and myself on all alternators.
>
>If you have a Glastar or other aircraft with a steel tube inner or outer
>cabin structure I would NOT use Bob's OVP module simply due to the poor
>effects of HI currents in the cabin. IE careful wiring and transient
>currents in the 50 amp or above might be hazardous to your flight
>instruments and as a minimum a compass accuracy check on an annual basis is
>recommended.
>
>In conclusion;
>
>There is simply no one size fits all that is safe to use. Most of the
>builders are safe with the externally regulated LR-3 setup. some will be
>unsafe with the use of Bob's OVP module and many are in the middle.
>
>However remember any who want to use the emergency mode of "No battery" need
>to know that both the LR-3 and the OVP module have a 100% chance of tripping
>the alternator off line with no battery and the often suggested addition of
>a 25,000 mfd capacitor to "stabilize the alternator regulator is by test not
>going to prevent false triggering of these devices from such simple things
>as turning off landing lights or strobes or recognition lights if the
>alternator is lightly loaded.
>
>No battery operation is my opinion a very important emergency mode of
>operation.
>
>Here is what Bob has recently stated on this subject "but the question of
>no-battery operation has never been addressed nor recommended in any of my
>writings"
>
>I agree that none of his suggested schematic designs allow this mode simply
>because they all include a LR-3 or OVP module that triggers with a load sump
>(that Bob requires the battery to clamp). No battery, no clamp, first event
>and alternator trips off line and no electrical power.
>
>But this is a different discussion.
>
>Sorry but as there is no one solution proposed todate we have no simple
>reply.
>
>Paul
>
>
>----- Original Message -----
>From: "Vincent Welch" <welchvincent(at)hotmail.com>
>To:
>Subject: RE: AeroElectric-List: OVP etc - do we have a bottom line?
>
>
> >
> >
> > A M E N ! ! !
> >
> >
> >>From: Richard Riley <Richard(at)RILEY.NET>
> >>Reply-To: aeroelectric-list(at)matronics.com
> >>To: aeroelectric-list(at)matronics.com
> >>Subject: AeroElectric-List: OVP etc - do we have a bottom line?
> >>Date: Fri, 01 Apr 2005 07:47:28 -0800
> >>
> >>
> >>I've now spent much of the night trying to read and understand all the
> >>objections to and defences of the crowbar OVP system.
> >>
> >>I still have no idea who's right. I just have a migraine.
> >>
> >>If I'm willing to spend enough money, can I build a system that satisfies
> >>all the critics? For example, many of the crowbar posts involve
> >>internally
> >>regulated alternators. If I'm using a B&C 60 amp alternator, an LR3, and
> >>SD8 and 2 batteries, am I still in danger of frying $50k worth of avionics
> >>because I blinked wrong?
> >>
> >>Please understand, I am willing to spend whatever it takes to make this
> >>problem (if it is a problem) go away. I don't want the "best" solution, I
> >>want all the solutions that are worthwhile and applicable. I'm not going
> >>to worry about an extra $100 for a transorb, I want belt and suspenders
> >>and
> >>nail gun and epoxy. Is that possible? Or are the approaches being
> >>described mutually incompatible?
> >>
> >>
> >
> >
> >
>
>
>--
>
>
>-- incoming mail is certified Virus Free.
Bob . . .
--------------------------------------------------------
< Throughout history, poverty is the normal condition >
< of man. Advances which permit this norm to be >
< exceeded -- here and there, now and then -- are the >
< work of an extremely small minority, frequently >
< despised, often condemned, and almost always opposed >
< by all right-thinking people. Whenever this tiny >
< minority is kept from creating, or (as sometimes >
< happens) is driven out of a society, the people >
< then slip back into abject poverty. >
< >
< This is known as "bad luck". >
< -Lazarus Long- >
<------------------------------------------------------>
http://www.aeroelectric.com
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: OVP etc - do we have a bottom line? |
>
>The CB max no damage current rating is a personal concern to some and not a
>big deal IF you have a real event as the alternator has failed. replacing
>the CB may or may not be needed. A purest will replace it most will simply
>press on by resetting. My objection is it does overstress the CB and a good
>design of OVP would limit the current so there would be no question.
The data I'm getting so far does not support the "no damage" interpretation
of the specification cited . . . but that's a study in process.
>The high current of hundreds of amps is a concern in some cases. It depends
>on if you have steel tubes in the cockpit (many of us do) and even if not
>the modern avionics sometimes include sensitive magnetometers that can be
>overloaded with hi currents nearby (near by can be more than 12" and still
>be too close. Finally if your engine depends on the 12 V bus to be above
>some voltage to run there is a potential case when the OVP module trips.
>this depends on the specific electronics. I have a documented case of
>certificated aircraft having major compass errors accumulating over time
>with currents around 50 amps max passing 18" away from the compass so it can
>be a concern (The mandatory service bulletin to correct this problem will
>be soon posted here for all to see).
Whoa! Where does that come from? This issue has been addressed
years ago and improved upon when b-leads were taken out of the
cockpit and bus bars were moved off the panel into fuse blocks.
Just about EVERY airplane has a placard saying that the compass
is calibrated with certain things ON or OFF. There are demonstrated
concerns and techniques involving wires carrying high static current
loads since the first generator went into an airplane. So what's that
have to do with a crowbar ov event? Every time you crank the engine
you have a 500-1000 amp event, why do we not agonize over that?
I had to chase a rat out of the woodpile on Bonanza compasses that
didn't like having the SD-20 alternator turned on . . . on the OTHER
side of the firewall . . . we went to the alternative compass location
on the windshield. Yes, every airplane has issues of electrically
induced magnetics but none of those issues are foundation for
dismissing the value or utility of a crowbar ov protection system.
>If you have a RV with Van's alternator add the recommended Transorbs and
>consider using Erics OVP approach. If you have the Aeroelectric OVP any
>false trip is unlikely to be a problem to the alternator with the added
>Transorbs.
>
>There is little probability of problems with the B & C conversion using the
>LR-3 regulator but adding "B" 'lead transorbs are recommended by both Eric
>and myself on all alternators.
>
>If you have a Glastar or other aircraft with a steel tube inner or outer
>cabin structure I would NOT use Bob's OVP module simply due to the poor
>effects of HI currents in the cabin. IE careful wiring and transient
>currents in the 50 amp or above might be hazardous to your flight
>instruments and as a minimum a compass accuracy check on an annual basis is
>recommended.
Unmitigated BS Paul . . .
>In conclusion;
>
>There is simply no one size fits all that is safe to use. Most of the
>builders are safe with the externally regulated LR-3 setup. some will be
>unsafe with the use of Bob's OVP module and many are in the middle.
How "unsafe" . . . are we talking about hazard to equipment or
hazard to people?
>However remember any who want to use the emergency mode of "No battery" need
>to know that both the LR-3 and the OVP module have a 100% chance of tripping
>the alternator off line with no battery and the often suggested addition of
>a 25,000 mfd capacitor to "stabilize the alternator regulator is by test not
>going to prevent false triggering of these devices from such simple things
>as turning off landing lights or strobes or recognition lights if the
>alternator is lightly loaded.
I have yet to see any data that shows alternator only operations
are compatible with the DO-160 suite of aviation products, much less
those for which you're trying to craft a kinder and gentler electrical
system. The dynamics of the voltage regulator's servo loop are "tuned"
with a battery on line. If one desires a regulator optimized for
no-battery operation, that can be supplied but to the present time,
no one has asked for it.
>No battery operation is my opinion a very important emergency mode of
>operation.
>
>Here is what Bob has recently stated on this subject "but the question of
>no-battery operation has never been addressed nor recommended in any of my
>writings"
>
>I agree that none of his suggested schematic designs allow this mode simply
>because they all include a LR-3 or OVP module that triggers with a load sump
>(that Bob requires the battery to clamp).
That was not the consideration at the the time. NOBODY but Barons
and Bonanzas allows battery-less operation by manipulation of
panel controls. There was a good reason for that long before the
manner and style of ov protection was considered. To imply that
I don't recommend battery-less operation just to satisfy some
feature of the ov protection system is a presumption of facts
not in evidence and patently untrue . . . I was there. I did it
and I know the foundation upon which the system was built.
> No battery, no clamp, first event
>and alternator trips off line and no electrical power.
Neither the LR-3 nor the OVM-14 was designed to accommodate the
battery-less system. They COULD be . . . the first question that needs
to be address is whether battery-less operations are broadly practical
and therefore recommendable. If that proves to be useful, a suitable
regulator and ov protection system can be designed for that service.
Please don't imply that the products presently offered are somehow
evil because they don't meet requirements not in place when those
components were designed.
If your suggesting a new environment, get it out there on paper
and let's explore the numbers. See my other posting.
Bob . . .
________________________________________________________________________________
| From: | owner-aeroelectric-list-server(at)matronics.com |
| Subject: | OVP etc - do we have a bottom line? |
Paul, please,
You are addressing a bunch of builders who are not as electrically and
electronically savvy as yourself. I cannot welcome your sweeping
generalizations.
Engineering has trained me to the fact that all design decisions are
compromises. KISS is a question of perspective. Look at the modern automatic
car - seen from the driver's point of view, you can hardly make it simpler -
it is KISS to the nth degree, but look at the complexity behind the
dashboard... Operating a Lycoming is certainly lots more complex than
operating a car but that is because the stuff behind the airplane's
dashboard is a lot simpler than a car's. Remember the old cars way back in
the 10's and 20's, very simple electrical systems, with manual advance,
priming... but what a chore to start them, to run them and to avoid damaging
them.
This being said, I'll say that Bob Knuckolls has done a tremendous amount of
work which has profited thousands of builders. I very much respect him and
shall listen to what he has to say. He has established a very high degree of
credibility. The last thing we want is to discourage him. I've seen good
people leave lists because things got a little out of hand.
Please remember that most of us are trying our best to make intelligent,
knowledgeable choices on subjects we are far from mastering and we need
people such as Bob, and you, to remain on the list and to respond
knowledgeably.
As for your past posts, I have found them mostly positive. If you could
possibly keep them that way I'd say great and thank you.
Michele Delsol
RV8 - Fuselage - France
> -----Original Message-----
> From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-
> aeroelectric-list-server(at)matronics.com] On Behalf Of Robert L. Nuckolls,
> III
> Sent: Monday, April 04, 2005 8:27 AM
> To: aeroelectric-list(at)matronics.com
> Subject: Re: AeroElectric-List: OVP etc - do we have a bottom line?
>
>
>
>
>
> >
> >I am sorry that the exchanges are so long and confusing (I am getting
> >confused myself).
> >
> >Much of the debate is regarding worst case design and the design approach
> of
> >the OVP that can false trigger.
> >
> >Then there is the current and the related CB ratings.
> >
> >Also there is the potential of alternator damage in the case of a false
> >trip.
> >
> >Lets go back and see where we are right now.
> >
> >The CB max no damage current rating is a personal concern to some and not
> a
> >big deal IF you have a real event as the alternator has failed. replacing
> >the CB may or may not be needed. A purest will replace it most will
> simply
> >press on by resetting. My objection is it does overstress the CB and a
> good
> >design of OVP would limit the current so there would be no question.
> >
> >The high current of hundreds of amps is a concern in some cases. It
> depends
> >on if you have steel tubes in the cockpit (many of us do) and even if not
> >the modern avionics sometimes include sensitive magnetometers that can be
> >overloaded with hi currents nearby (near by can be more than 12" and
> still
> >be too close. Finally if your engine depends on the 12 V bus to be above
> >some voltage to run there is a potential case when the OVP module trips.
> >this depends on the specific electronics. I have a documented case of
> >certificated aircraft having major compass errors accumulating over time
> >with currents around 50 amps max passing 18" away from the compass so it
> can
> >be a concern (The mandatory service bulletin to correct this problem
> will
> >be soon posted here for all to see).
> >
> >If you have a RV with Van's alternator add the recommended Transorbs and
> >consider using Erics OVP approach. If you have the Aeroelectric OVP any
> >false trip is unlikely to be a problem to the alternator with the added
> >Transorbs.
> >
> >There is little probability of problems with the B & C conversion using
> the
> >LR-3 regulator but adding "B" 'lead transorbs are recommended by both
> Eric
> >and myself on all alternators.
> >
> >If you have a Glastar or other aircraft with a steel tube inner or outer
> >cabin structure I would NOT use Bob's OVP module simply due to the poor
> >effects of HI currents in the cabin. IE careful wiring and transient
> >currents in the 50 amp or above might be hazardous to your flight
> >instruments and as a minimum a compass accuracy check on an annual basis
> is
> >recommended.
> >
> >In conclusion;
> >
> >There is simply no one size fits all that is safe to use. Most of the
> >builders are safe with the externally regulated LR-3 setup. some will be
> >unsafe with the use of Bob's OVP module and many are in the middle.
> >
> >However remember any who want to use the emergency mode of "No battery"
> need
> >to know that both the LR-3 and the OVP module have a 100% chance of
> tripping
> >the alternator off line with no battery and the often suggested addition
> of
> >a 25,000 mfd capacitor to "stabilize the alternator regulator is by test
> not
> >going to prevent false triggering of these devices from such simple
> things
> >as turning off landing lights or strobes or recognition lights if the
> >alternator is lightly loaded.
> >
> >No battery operation is my opinion a very important emergency mode of
> >operation.
> >
> >Here is what Bob has recently stated on this subject "but the question of
> >no-battery operation has never been addressed nor recommended in any of
> my
> >writings"
> >
> >I agree that none of his suggested schematic designs allow this mode
> simply
> >because they all include a LR-3 or OVP module that triggers with a load
> sump
> >(that Bob requires the battery to clamp). No battery, no clamp, first
> event
> >and alternator trips off line and no electrical power.
> >
> >But this is a different discussion.
> >
> >Sorry but as there is no one solution proposed todate we have no simple
> >reply.
> >
> >Paul
> >
> >
> >----- Original Message -----
> >From: "Vincent Welch" <welchvincent(at)hotmail.com>
> >To:
> >Subject: RE: AeroElectric-List: OVP etc - do we have a bottom line?
> >
> >
> > >
> > >
> > > A M E N ! ! !
> > >
> > >
> > >>From: Richard Riley <Richard(at)RILEY.NET>
> > >>Reply-To: aeroelectric-list(at)matronics.com
> > >>To: aeroelectric-list(at)matronics.com
> > >>Subject: AeroElectric-List: OVP etc - do we have a bottom line?
> > >>Date: Fri, 01 Apr 2005 07:47:28 -0800
> > >>
>
> > >>
> > >>I've now spent much of the night trying to read and understand all the
> > >>objections to and defences of the crowbar OVP system.
> > >>
> > >>I still have no idea who's right. I just have a migraine.
> > >>
> > >>If I'm willing to spend enough money, can I build a system that
> satisfies
> > >>all the critics? For example, many of the crowbar posts involve
> > >>internally
> > >>regulated alternators. If I'm using a B&C 60 amp alternator, an LR3,
> and
> > >>SD8 and 2 batteries, am I still in danger of frying $50k worth of
> avionics
> > >>because I blinked wrong?
> > >>
> > >>Please understand, I am willing to spend whatever it takes to make
> this
> > >>problem (if it is a problem) go away. I don't want the "best"
> solution, I
> > >>want all the solutions that are worthwhile and applicable. I'm not
> going
> > >>to worry about an extra $100 for a transorb, I want belt and
> suspenders
> > >>and
> > >>nail gun and epoxy. Is that possible? Or are the approaches being
> > >>described mutually incompatible?
> > >>
> > >>
> > >
> > >
> > >
> >
> >
> >--
> >
> >
> >-- incoming mail is certified Virus Free.
>
>
> Bob . . .
>
>
> --------------------------------------------------------
> < Throughout history, poverty is the normal condition >
> < of man. Advances which permit this norm to be >
> < exceeded -- here and there, now and then -- are the >
> < work of an extremely small minority, frequently >
> < despised, often condemned, and almost always opposed >
> < by all right-thinking people. Whenever this tiny >
> < minority is kept from creating, or (as sometimes >
> < happens) is driven out of a society, the people >
> < then slip back into abject poverty. >
> < >
> < This is known as "bad luck". >
> < -Lazarus Long- >
> <------------------------------------------------------>
> http://www.aeroelectric.com
>
>
>
>
>
________________________________________________________________________________
| Subject: | Re: OVP etc - do we have a bottom line? |
| From: | Gerry Holland <gnholland(at)onetel.com> |
Bonjour Michele
Bravo! at your entente cordiale! regarding OVP.
It came just in time as the subject had lost it's interest and caused me
enough aggravation to consider to unsubscribe, something I was not keen to
do.
The OBAM community can make choices for reliability and safety and many wise
words are said here in that vein. Recent technical discussions are aimed
down at a technical level that only leads to confusion and some self doubt
on earlier decisions.
For myself. I want a clear indication of a problem and then apply that to a
set of rehearsed actions to ensure that problem does not escalate to a fatal
conclusion. Many of the suggestions made help in that endeavour,
unfortunately they also contradict based on the fervour of each opinion
stated.
Come on Gentlemen! A short list of what criteria are essential to be met and
why, based on experience and proven reliability.
Salutations Cordiale Michele
Gerry
Europa 384 G-FIZY
Trigear with Rotax 912 and Arplast CS Prop.
Dynon EFIS, KMD 150, Icom A-200 and SL70 Transponder.
PSS AoA Fitted.
http://www.g-fizy.com
Mobile: +44 7808 402404
WebFax: +44 870 7059985
gnholland(at)onetel.com
________________________________________________________________________________
| From: | "n801bh(at)netzero.com" <n801bh(at)NetZero.com> |
| Subject: | Re: Fresh approach |
> best,
> .pdf's are most acceptable but I'll work with crayon on toilet paper
> if necessary. If you're offering the next greatest thing, let's get
> it out there for folks to exploit. I've hidden nothing, you've
> revealed nothing.
>
> Bob . . .
>
> "VERY WELL PUT" Bob. I have endured the same reception from
people in several internet chat rooms on my auto engine conversion. Virtually
all claims my powerplant wouldn't work came from arm chair engineers and nay
sayers who couldn't take apart a ball point pen. I have been in the racing,
fabricating and designing business longer then I care to admit. This is my first
homebuilt, and I try to think EVERYTHING through. So far it flies great, runs
real smooth, is getting better the expected fuel burn and most of all, it is not
following the "certified" designs of 60 year old technology.
> Of course anyone putting several times the HP in an airframe has to pushing
the envelope for sure, I knew it going in, planned for as many outcomes as
possible and used the best parts available.
>
> I admit the other guy has made some well versed statements and sounds up
to speed on the topic but like anything else ," the proof is in the
pudding". I speak for myself and probably a lot of other OBAM out there.
Bob has been there for us using common sense to help us wire our toys and I for
one certainly appreaciate it. Chin up Bob.
>
>
> Ben Haas
> N801BH
> www.haaspowerair.com
>
Ben Haas
N801BH
www.haaspowerair.com
________________________________________________________________________________
| From: | Mickey Coggins <mick-matronics(at)rv8.ch> |
| Subject: | Re: Fresh approach |
> ... I have endured the same reception from
> people in several internet chat rooms on my auto engine conversion. Virtually
> all claims my powerplant wouldn't work came from arm chair engineers and nay
> sayers who couldn't take apart a ball point pen.
Ben,
As I learned in my high school chemistry class, "the universe is
entropy". It's much easier to tear things down than to
build them up.
Your engine package looks very slick. I love the photo on your
site where it looks like the VP is trying to get you trade aircraft.
BTW, do you have your wiring schematic somewhere up where I
can check it out? I assume your engine is electrically dependent,
like mine. I'm always interested in looking at how others have
done it.
Thanks,
Mickey
--
Mickey Coggins
http://www.rv8.ch/
#82007 Wiring
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: PMags and RPM |
>
>I'm a happy owner of an Emag and have spoken to the owners at length about
>the E & P models. So I'll quote what I know from memory, which we know can
>be flaky at times :)
>
>They have a big following in the plastic plane arena, and are gathering
>interest with the RV community. They did not indicate they monitor any
>'lists', they are simply working hard to start a new business and answer
>questions.
>
> From what I understand about the PMag.which I don't own, but may someday.
>The generator puts out 12-14V at approx. 1500 RPM, and drops voltage output
>as the RPM drops. The PMag & Emag will still make spark at some ridiculous
>low number like 5 V. So by generating 5+ V at 800 RPM it is self
>sustaining.
This feature in the E-mag's low voltage operation also says that
it's not subject to wandering off into the weeds during a starter-inrush
brownout . . . a battery powered ignition system truly designed to live
in the current world of aircraft DC power systems.
> The deal is - it has no excess voltage that can charge a
>battery below 1500 RPM, but it can help in a failed alternator situation
>above that RPM. Of course the output would be a very low amperage, and I
>wouldn't count on continued flight after an alternator failure.
An you wouldn't want it to. Having a DEDICATED low energy power source
to support a low energy but very important operating requirement is
good design. Further, given that the energy requirements for the e-mag
are so low, it represents a lower energy budget for calculating battery-
only operations. Adding the "p-" only shifts alternator out ignition loads
from battery to internal power source . . . and in my mind that's a good
thing.
>That is the gist of it - no hard numbers - do some research on the website -
>your mileage will vary - and I love this list and it's wealth of
>information!
>
>Kelly Patterson
>RV-6A finishing & wiring
>PHX, AZ
>
>
>I think this sounds like a good question to ask the people that make the
>PMags. Does someone that plays a principle role in the company monitor
>the list?
I don't think so. I've spoken with them and had e-mails from them
directly but my sense is that they do not participate on the
AeroElectric-List.
They might be on others.
I'm planning a trip down to visit them this spring sometime.
> > In case of the unlikely scenario that the electrical system should die
> > and the RPM should fall below PMag's self sustaining level, would wind
> > milling by diving bring the engine RPM up sufficiently, thereby
> > restoring engine power?
> >
> > A similar scenario would occur as one is on short final with engine at
> > 800 RPM. If the electrical system is down, are we in a situation
> > whereby the PMag could stop generating its own electricity, thereby
> > committing the flight to a definitive landing no matter what, i.e. no
> > go around possibility?
If you had a dark panel and knew that the p-mag needed minimal
engine speed to continue to function, why would you ALLOW rpm
to drop below some minimum value until your comfortable arrival
was assured?
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Fresh approach |
>
>
>
> > best,
> > .pdf's are most acceptable but I'll work with crayon on toilet paper
> > if necessary. If you're offering the next greatest thing, let's get
> > it out there for folks to exploit. I've hidden nothing, you've
> > revealed nothing.
> >
> > Bob . . .
> >
> > "VERY WELL PUT" Bob. I have endured the same reception from
>people in several internet chat rooms on my auto engine conversion. Virtually
>all claims my powerplant wouldn't work came from arm chair engineers and nay
>sayers who couldn't take apart a ball point pen. I have been in the racing,
>fabricating and designing business longer then I care to admit. This is my
>first
>homebuilt, and I try to think EVERYTHING through.
And you've probably discovered, it's very USEFUL to have conversations
with others who understand the role of good critical design review . .
. they
are invaluable resources for thinking EVERYTHING trough. It's a win-win
. . .
either good ideas are deduced as sound and bad ideas are prevented from
going into production.
> So far it flies great, runs
>real smooth, is getting better the expected fuel burn and most of all, it
>is not
>following the "certified" designs of 60 year old technology.
> > Of course anyone putting several times the HP in an airframe has to
> pushing
>the envelope for sure, I knew it going in, planned for as many outcomes as
>possible and used the best parts available.
> >
> > I admit the other guy has made some well versed statements and sounds up
>to speed on the topic but like anything else ," the proof is in the
>pudding". I speak for myself and probably a lot of other OBAM out there.
>Bob has been there for us using common sense to help us wire our toys and
>I for
>one certainly appreaciate it. Chin up Bob.
Thank you. This isn't a battle to be won or lost. It's an arena of ideas
wherein every idea should be evaluated for suitability to task. The hard
part is defining "task" and "suitability" in real numbers and failure
mode effects analysis and then fitting that to the marketplace.
Eric's description of what he would do "if it were my airplane" has offered
the greatest insight yet. Single bus, manual battery switch, alternator as
reliable as prop bolts, but add Transorbs no so much for real OV
protection as
for load-dump protection when a battery that is NOT as reliable as prop
bolts
opens up.
My philosophy for design assumes that any part of the airplane can fail and
to offer architectures that mitigate various levels of failures to be
tolerated depending on how the airplane is equipped and used.
The "new age" system still needs a second battery of some kind to support
products not designed to live in the "old age" aircraft systems that wander
of into the weeds during starter inrush brownout intervals. The "new
age" system would still need battery bus(ses) to support system-cold ops
of things like dome lights and, of course, those items not designed to live
in the "old age" system.
So the full-up, "new age" system is still a three bus system (figure z-11
with a second battery, no e-bus, manual battery switches, no alternator
control switch, no OV protection, and transorbs for mitigating the
inevitable load dump transients from an alternator running sans battery.
One would also want to have a definitive part numbers and manufacturers
who offers the alternator as reliable as prop bolts and it wouldn't
hurt to offer part numbers and manufacturers of batteries that are
also blessed with superior reliability. I chose to offer architectures
wherein I don't care what alternator (or battery) is used. The "new age"
system
should be very specific as to components suited to the task. I would also
be interested in the battery servicing philosophy . . . can we run this
battery 'til it dosen't crank the engine any more? We can run airborne
without it comfortably . . . it seems that one goal of the "new age" system
is to wring every last watt-second of functionality out of the battery.
Or, should we still do attentive preventative maintenance on the battery
so as to support alternator-out operations . . . oops, no that guy is
as reliable as prop bolts so we can run the battery dry.
For the first time, I think I'm getting a picture of what's being proposed.
How about it Eric and Paul, am I close? Please correct any misconceptions.
As soon as the architecture and recommended operating philosophies are
defined, ONLY THEN do we know enough about it to ask/answer the definitive
questions for an FMEA and the sifting of simple-ideas.
Bob . . .
________________________________________________________________________________
| From: | "Vern W." <vernw(at)ev1.net> |
| Subject: | Re: OVP etc - do we have a bottom line? |
> Come on Gentlemen! A short list of what criteria are essential to be met
and
> why, based on experience and proven reliability.
>
> Salutations Cordiale Michele
The difficulty I'm having with the current OVP debate is that, besides
being above my head, these solutions are being presented as one-fits-all
arrangements (Crowbar good/bad, Transorb good/bad... whatever). I
understand the "meat" (schematics) of the electronics going on, but I don't
understand the philosophy with regard to negative effects downstream of an
OVP initiation and where I might better use one type of OVP over the other.
I make this comment thinking that I'm not alone among the non-pros who are
lurking here in the AE list hoping to find some help.
There are reasons why different people choose different "basic" systems
to go with our specific applications, and I'm having trouble trying to fit
in parts of this discussion with what I am specifically trying to do.
For example, and specifically in my case, I like the basic design
philosophy of Bob's Z-13, but I'm uncomfortable with what I see as a weak
link being what happens if a battery terminal breaks, i.e., both alternators
become just dead weight. At the same time, I don't feel the need or expense
of going with a full "split" dual alt/dual batt system like the Z-14.
So what I'd like to do is to stay with the Z-13 system and "simply" add
an additional 4.5amp battery somewhere in the system that will serve as both
a backup power source for JUST the electronic ignition (as recommended by
Lightspeed), AND as an exciter for either of the alternators. I want the
4.5amp battery to be able to be charged by either alternator, but to only
supply power to the ignition unless intentionally switched into the Aux.
buss. A system like that, and with bullet-proof OVP (whether Crowbar or
Transorb), will allow me to happily fly over mountains and large bodies of
water.
I'm just not up to speed on where this OVP debate fits in with what I am
wanting to do.
Vern
----- Original Message -----
From: "Gerry Holland" <gnholland(at)onetel.com>
Subject: Re: AeroElectric-List: OVP etc - do we have a bottom line?
>
> Bonjour Michele
>
> Bravo! at your entente cordiale! regarding OVP.
>
> It came just in time as the subject had lost it's interest and caused me
> enough aggravation to consider to unsubscribe, something I was not keen to
> do.
>
> The OBAM community can make choices for reliability and safety and many
wise
> words are said here in that vein. Recent technical discussions are aimed
> down at a technical level that only leads to confusion and some self doubt
> on earlier decisions.
>
> For myself. I want a clear indication of a problem and then apply that to
a
> set of rehearsed actions to ensure that problem does not escalate to a
fatal
> conclusion. Many of the suggestions made help in that endeavour,
> unfortunately they also contradict based on the fervour of each opinion
> stated.
>
> Come on Gentlemen! A short list of what criteria are essential to be met
and
> why, based on experience and proven reliability.
>
> Salutations Cordiale Michele
>
> Gerry
>
> Europa 384 G-FIZY
> Trigear with Rotax 912 and Arplast CS Prop.
> Dynon EFIS, KMD 150, Icom A-200 and SL70 Transponder.
> PSS AoA Fitted.
>
> http://www.g-fizy.com
> Mobile: +44 7808 402404
> WebFax: +44 870 7059985
> gnholland(at)onetel.com
>
>
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: OVP etc - do we have a bottom line? |
>
>Gentlemen:
>
>I seem to be getting copies of material that you may not want public?
>I am not part of your group or organisation and really don't need to
>know about your unsolved stress points. I have been receiving several
>of these emails this evening?
Don't know who wouldn't want it public. I have nothing
to hide and don't believe I've done anything I should
be ashamed of.
What we're discussing is a alternative architecture and
fabricating philosophy for an aircraft electrical system
design. It may have a great deal of merit but we won't
know until all is laid out on the table for everyone to
ponder and formulate questions that are part of any
good critical design review.
If you detect some stress in my words, be advised that it's
only frustration and not anger. But I am to the point where
I'll have to insist on forthright and open participation of
the other participants for me to continue. At the moment
I don't see ideas and understanding moving forward and I
do have other things to do if this train doesn't get moving.
I'm comfortable with either outcome.
Bob . . .
________________________________________________________________________________
| From: | "Troy Scott" <tscott1217(at)bellsouth.net> |
| Subject: | Eric's Plans/ Failure Modes? |
Eric,
Would you please discuss possible failure modes with your plan for your
GlaStar?
Please include the maintenance required after each failure, and how you
would go about performing said maintenance (how invasive is it?, etc..)
Regards,
Troy
ERIC WROTE:
My opinion only---and I have a lot of them. I am building a Glastar and as
of this date, here's what I believe is going into it----
1) I would buy a new or expertly rebuilt internally regulated Nippondenso
55A (or so).
2) I would use a fusible link as the B+ lead from the alternator and hang
off it 6 X 5kW 18V unidirectional Transorbs (and one or two bi-directionals
around, too). It would be fine and perhaps preferable to distribute these
Transorbs, the reason being that a lightning strike might well do less
damage is the transorbs are generally sprinkled instead of grouped.
3) Battery disconnect contactor would be eliminated but if the FAA wants it
then I would design this as a pull-to-disconnect mechanical switch at the
battery terminals (from car racing products). Use only in a real crash
emergency and maybe a half-way-decent anti-theft device.
All the details of busses and batteries need to be worked out. But this is a
core part. No crowbar, no OVP, no alternator contactor, no battery
contactor, no external regulator, no field breaker, no load dump concerns,
maximum reliability, minimum cost and weight.
Regards,
Eric M. Jones
www.PerihelionDesign.com
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Zeftronics transistor |
>
>
>I have a Zeftronics R15100 voltage regulator that is blown because the
>previous owner of the plane used a shielded wire on the alternator without
>the shield insulated and it shorted to the field stud on the alternator.
Yup . . . field shorts will take down many regulator designs . . . A
B&C LR-3 uses the crowbar system to shut down the supply and protect the
regulator in case of a field short.
>The TO-220 output transistor is toasted and I can't read the complete part
>number on it. It is a TIP1 something. If I had to take a wild ass guess I
>would say a TIP120 is the most likely candidate, but I want to be sure.
>Does anyone know for sure or know where I can get a schematic?
You might call Zeftronics and ask . . . as for Femmi (assming
he's still there). He might just tell you the part number.
It's a plain vanilla transistor. Get someting good for 5A or more,
80v or more. Try a PNP and operate if from a variable power supply
on the bench using a 10 ohm resistor for a "field" load. 99% sure
this will fix it. I've not seen a practical approach to using an
NPN transistor in that slot on a regulator.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> pinout... |
| Subject: | Re: Looking for a B&C oil pressure switch |
pinout...
pinout...
>
>
>Ok, I got one of the three connector switches. Normally I've seen the
>connections
>Marked as C, NC, and NO. On this one they are marked P, S, and I... So.
>Which ones
>Are which? w/o pressure, P and S are shorted... But I don't know which
>one of them
>Is the "common" lead...
I used to sell that switch and thought I had the data on it but
can't put my hands on it. Call Tim at B&C.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | RE: OVP etc - Bottom Line - Seeds of Z-20 are planted! |
>
>Paul Messinger forced all this to condense and the more I look at it the
>more I like it.
>
>My opinion only---and I have a lot of them. I am building a Glastar and as
>of this date, here's what I believe is going into it----
>
>1) I would buy a new or expertly rebuilt internally regulated Nippondenso
>55A (or so).
>
>2) I would use a fusible link as the B+ lead from the alternator and hang
>off it 6 X 5kW 18V unidirectional Transorbs (and one or two bi-directionals
>around, too). It would be fine and perhaps preferable to distribute these
>Transorbs, the reason being that a lightning strike might well do less
>damage is the transorbs are generally sprinkled instead of grouped.
>
>3) Battery disconnect contactor would be eliminated but if the FAA wants it
>then I would design this as a pull-to-disconnect mechanical switch at the
>battery terminals (from car racing products). Use only in a real crash
>emergency and maybe a half-way-decent anti-theft device.
>
>All the details of busses and batteries need to be worked out. But this is a
>core part. No crowbar, no OVP, no alternator contactor, no battery
>contactor, no external regulator, no field breaker, no load dump concerns,
>maximum reliability, minimum cost and weight.
Thank you sir! Let me take these words and begin to craft Z-20. I'll
publish the drawing as soon as I can and you can start feeding me errata
and we can begin to discuss the companion notes that will help the
neophyte builder achieve the perceived performance levels.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
>
>Listers,
>
>I have a relay with hooks on it as supplied with my FADEC Cabin harness kit.
>Pictures available at http://home.comcast.net/~mtaylo17/RV7/fadec.htm#Latest
>
>Does anybody know how I'm supposed to make a connection to this thing? Right
>now, I'm assuming I twist a loop in the wire, hook it on and solder it.
>
>Seems to go against convention of not soldering stuff if you can help it.
Yup, those are solder-hooks. Wrap the wire around it, solder it, cover with
heatshrink.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: RAC Trim noise |
><Gilles.Thesee@ac-grenoble.fr>
>
>Hi all,
>
>I would appreciate your opinion about the following point :
>In our Rotax 914 powered MCR 4S, the only electrical noise audible is
>from the small RAC Trim in the right aileron, not far from the Bob
>Archer's VHF antenna in the wingtip. This is not a real nuisance, since
>the aileron trim is seldom used in flight.
>Nevertheless would a capacitor across the trim motor wires improve things ?
>
>Thanks for your advice,
>Regards,
Probably. Try 1000 pf ceramic capacitor across motor leads (white wires).
Bob . . .
________________________________________________________________________________
| From: | "Ron Raby" <ronr(at)advanceddesign.com> |
To everyone:
I am having a problem with my push to talk on the pilot side. On the ground
and for a while during flight the push to talk works fine. It then stops
working. The copilot side works fine. The parts involved are the PS
engineering pma 7000, approach systems hub, approach system cables, Garmin
530 and an SL30.
I have rang out the cables directly up to the pma 7000. I cannot find a
problem. I have rang out the switch both when it is working and not and it
is ok. I have shut of the intercom during flight and it still does not work.
my gut feeling is something is not working in the pma 7000 when it gets
warm. Ideas would be appreciated.
Thanks
Ron Raby
Lancair ES
flying
----- Original Message -----
From: "Mickey Coggins" <mick-matronics(at)rv8.ch>
Subject: Re: AeroElectric-List: Re: Fresh approach
>
>
>> ... I have endured the same reception from
>> people in several internet chat rooms on my auto engine conversion.
>> Virtually
>> all claims my powerplant wouldn't work came from arm chair engineers and
>> nay
>> sayers who couldn't take apart a ball point pen.
>
> Ben,
>
> As I learned in my high school chemistry class, "the universe is
> entropy". It's much easier to tear things down than to
> build them up.
>
> Your engine package looks very slick. I love the photo on your
> site where it looks like the VP is trying to get you trade aircraft.
>
> BTW, do you have your wiring schematic somewhere up where I
> can check it out? I assume your engine is electrically dependent,
> like mine. I'm always interested in looking at how others have
> done it.
>
> Thanks,
> Mickey
>
> --
> Mickey Coggins
> http://www.rv8.ch/
> #82007 Wiring
>
>
>
________________________________________________________________________________
| Subject: | Re: RAC Trim noise |
>>Nevertheless would a capacitor across the trim motor wires improve things ?
>>
>>Thanks for your advice,
>>Regards,
>>
>>
>
> Probably. Try 1000 pf ceramic capacitor across motor leads (white wires).
>
>
>
Bob,
Thanks a lot.
Regards,
Gilles Thesee
Grenoble, France
________________________________________________________________________________
| From: | Harley <harley(at)AgelessWings.com> |
| Subject: | Re: Looking for a B&C oil pressure switch pinout... |
>>they are marked P, S, and I...<<
Interesting...on the B&C website, the picture of that switch shows the
same terminology, but when clicking on the wiring diagram for it, it
shows, as you said, NC, NO and C!
If you do contact Tim, suggest that they change the wiring diagram!
Anyway, it sounds like you have a meter or a continuity device of some
kind to be able to determine that P and S are continuous with no
pressure, so one of them must be the common, and the other is the NC
terminal.
To determine which, I'd just put about 10 pounds of air pressure on it,
while having my meter leads connected to I and S, then again with I and
P...whichever one gives you continuity, is the common. And of course, I
is the NO lead.
Harley Dixon
Robert L. Nuckolls, III pinout... wrote:
pinout...
>
>
>
>
>>
>>
>>Ok, I got one of the three connector switches. Normally I've seen the
>>connections
>>Marked as C, NC, and NO. On this one they are marked P, S, and I... So.
>>Which ones
>>Are which? w/o pressure, P and S are shorted... But I don't know which
>>one of them
>>Is the "common" lead...
>>
>>
>
> I used to sell that switch and thought I had the data on it but
> can't put my hands on it. Call Tim at B&C.
>
> Bob . . .
>
>
>
>
________________________________________________________________________________
| From: | "Eric Ruttan" <ericruttan(at)chartermi.net> |
Dear Mr. Nuckolls;
Last time I commented on this topic a very well known engineer ran away and
did not come back for months. I do not desire a repeat of that but I think
there are some problems that have not been addressed.
It is with deep personal respect for your thinking process and work ethic I
send these comments.
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
> .pdf's are most acceptable but I'll work with crayon on toilet paper
> if necessary. If you're offering the next greatest thing, let's get
> it out there for folks to exploit. I've hidden nothing, you've
> revealed nothing.
>
> Bob . . .
"I've hidden nothing, you've revealed nothing."
This is the single point I have perceived from the very beginning of this
discussion months ago. Claims are made. Ideas are shouted. But not a
single simple idea critique has been proposed. Not a single, real world,
valid critique, of any Z diagram has been made. Not single actually
verifiable experiment or test has been shown in support of this "critique".
In fact you have done experiments in response to these vague claims to
quantify an area of these vague claims as not valid.
Bob, at what point do you stop repeating yourself and realize your request
for clarification is not being addressed? At what point to you stop doing
work to disprove or quantify accusers unsupported and vague claims? When
should they be responsible for SUPPORTING data behind a critique, OR EVEN
CLEARLY ARTICULATING said critique?
> And you've probably discovered, it's very USEFUL to have conversations
> with others who understand the role of good critical design review . .
> . they
> are invaluable resources for thinking EVERYTHING trough. It's a
win-win
> . . .
> either good ideas are deduced as sound and bad ideas are prevented
from
> going into production.
I totally agree in the value of peer review. Bob, let me humbly suggest
this is not what is happening here. What I see is a vague and changing
critique of a well proven design. I see no clear articulation of simple
ideas or raw data to suggest we can even begin to determine what the
critique is. How can a discussion occur when peer reviewer will not clarify
to a "simple idea" the critique? I see you, Bob, having a discussion with
what you think they mean. I see you building an experiment showing an
entire area of these vague claims are not supported in your experiments.
The response to your experiment was to ask about parts, not get into the lab
and repeat it. Bob, what does that mean to you? It holds great meaning for
me.
> > Chin up Bob.
>
> Thank you. This isn't a battle to be won or lost. It's an arena of
ideas
> wherein every idea should be evaluated for suitability to task.
In your world it is an arena of ideas. But you are in the arena with
someone who wont share/talk about/quantify ideas. If that is true, and it
may not be, then I suggest you question your premise about where you are.
> The hard
> part is defining "task" and "suitability" in real numbers and failure
> mode effects analysis and then fitting that to the marketplace.
Bob, task is not hard. This "peer" discussion has refused to even addressed
task.
I cut your response to Eric's post. It also takes us down the same path.
Eric is a very bright guy. He knows that saying "I would do this" is
useless. It is the "because" that matters, which for some reason is missing
from his post.
Again I thank you for your time.
Eric
________________________________________________________________________________
| From: | "Mike Larkin" <mlas(at)cox.net> |
I'm thinking ignition noise from a bad plug lead could be your problem.
Mike Larkin
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Chris
Horsten
Subject: RE: AeroElectric-List: Help!
Hi Matt,
Thanks for this hints
It's a Zenith CH-250. A further report from the ferry pilot reveals that
there is power. Radio is good during a message received, but reverts to
static once it ends. I will advise them re the TX as they probably don't
know that (I didn't). The aircraft was running perfect up until now. No
known issues. We did switch out the encoder about a week ago because the
last one seemed bad.
Re voltage being low I don't think this is the problem. Something is
generating some noise, because even the hand held is acting up and it is
operating on its own power. Engine is running fine and was started up at
least twice for a circuit after the problem surfaced. They are handing
off
to a mechanic this am I believe.
Other possible sources: Master relay? Noise filter (capacitor)? Voltage
regulator?
Chris
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of
mprather
Subject: Re: AeroElectric-List: Help!
Random questions and comments:
If it were the brushes, I would guess that there would be some warning
symptoms. I have had alternator brushes go bad before, and normally,
the
alternator light starts to flash occasionally, or just at start up.
Finally it gets bad enough that the battery is not getting charged, and
then
is dead.
Is this airplane new, or new to your friend? I am wondering about pre
existing, but undisclosed problems, like maybe the charging system never
actually worked, but the seller sent them on their way with a charged
battery. Now maybe it's low?
Does the engine crank okay with battery power?
Do the stranded folks have any diagnostic instrumentation at their
disposal?
It would be helpful if they either have a panel mounted volt/charging
meter,
or even better, if they have access to a multimeter. Check the battery
voltage with everything turned off, then again with the engine running.
My Narco transponder light stays on solid for the first few minutes of
operation (I assume during warmup). I wonder if they have left the txp
on
long enough to warm up.
I also wonder if bus voltage is so low that the com radio is having
problems
operating.
I am not a generator expert.. I sort of doubt the generator has the
capability to raise the bus voltage high enough to damage anything, but
I
could be wrong.
If the system is actually pretty standard, find a mech to take a look at
it.
Is the airplane a Tailwind (random shot - I couldn't think of any other
OBAM
aircraft that have O-300's)?
Good luck. Keep us posted..
Regards,
Matt-
--
--
________________________________________________________________________________
| From: | "Mike Larkin" <mlas(at)cox.net> |
How long did the system work until it failed or started giving you
problems? Does the problem happen on both com radios the same way?
If so I think you are on the right track, it sounds like it is the audio
panel (PMA 7000). Give PS-Engineering a call and see if this is a
common problem. There are good people at PS-Engineering.
Mike Larkin
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Ron
Raby
Subject: AeroElectric-List: ptt problem
To everyone:
I am having a problem with my push to talk on the pilot side. On the
ground
and for a while during flight the push to talk works fine. It then stops
working. The copilot side works fine. The parts involved are the PS
engineering pma 7000, approach systems hub, approach system cables,
Garmin
530 and an SL30.
I have rang out the cables directly up to the pma 7000. I cannot find a
problem. I have rang out the switch both when it is working and not and
it
is ok. I have shut of the intercom during flight and it still does not
work.
my gut feeling is something is not working in the pma 7000 when it gets
warm. Ideas would be appreciated.
Thanks
Ron Raby
Lancair ES
flying
----- Original Message -----
From: "Mickey Coggins" <mick-matronics(at)rv8.ch>
Subject: Re: AeroElectric-List: Re: Fresh approach
>
>
>> ... I have endured the same reception from
>> people in several internet chat rooms on my auto engine conversion.
>> Virtually
>> all claims my powerplant wouldn't work came from arm chair engineers
and
>> nay
>> sayers who couldn't take apart a ball point pen.
>
> Ben,
>
> As I learned in my high school chemistry class, "the universe is
> entropy". It's much easier to tear things down than to
> build them up.
>
> Your engine package looks very slick. I love the photo on your
> site where it looks like the VP is trying to get you trade aircraft.
>
> BTW, do you have your wiring schematic somewhere up where I
> can check it out? I assume your engine is electrically dependent,
> like mine. I'm always interested in looking at how others have
> done it.
>
> Thanks,
> Mickey
>
> --
> Mickey Coggins
> http://www.rv8.ch/
> #82007 Wiring
>
>
>
--
--
________________________________________________________________________________
| From: | "Chris Horsten" <airplanes(at)sympatico.ca> |
Thanks Mike,
That's one thing no one has thought of yet.
Chris
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Mike
Larkin
Subject: RE: AeroElectric-List: Help!
I'm thinking ignition noise from a bad plug lead could be your problem.
Mike Larkin
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Chris
Horsten
Subject: RE: AeroElectric-List: Help!
Hi Matt,
Thanks for this hints
It's a Zenith CH-250. A further report from the ferry pilot reveals that
there is power. Radio is good during a message received, but reverts to
static once it ends. I will advise them re the TX as they probably don't
know that (I didn't). The aircraft was running perfect up until now. No
known issues. We did switch out the encoder about a week ago because the
last one seemed bad.
Re voltage being low I don't think this is the problem. Something is
generating some noise, because even the hand held is acting up and it is
operating on its own power. Engine is running fine and was started up at
least twice for a circuit after the problem surfaced. They are handing off
to a mechanic this am I believe.
Other possible sources: Master relay? Noise filter (capacitor)? Voltage
regulator?
Chris
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of mprather
Subject: Re: AeroElectric-List: Help!
Random questions and comments:
If it were the brushes, I would guess that there would be some warning
symptoms. I have had alternator brushes go bad before, and normally, the
alternator light starts to flash occasionally, or just at start up.
Finally it gets bad enough that the battery is not getting charged, and then
is dead.
Is this airplane new, or new to your friend? I am wondering about pre
existing, but undisclosed problems, like maybe the charging system never
actually worked, but the seller sent them on their way with a charged
battery. Now maybe it's low?
Does the engine crank okay with battery power?
Do the stranded folks have any diagnostic instrumentation at their disposal?
It would be helpful if they either have a panel mounted volt/charging meter,
or even better, if they have access to a multimeter. Check the battery
voltage with everything turned off, then again with the engine running.
My Narco transponder light stays on solid for the first few minutes of
operation (I assume during warmup). I wonder if they have left the txp on
long enough to warm up.
I also wonder if bus voltage is so low that the com radio is having problems
operating.
I am not a generator expert.. I sort of doubt the generator has the
capability to raise the bus voltage high enough to damage anything, but I
could be wrong.
If the system is actually pretty standard, find a mech to take a look at it.
Is the airplane a Tailwind (random shot - I couldn't think of any other OBAM
aircraft that have O-300's)?
Good luck. Keep us posted..
Regards,
Matt-
--
--
________________________________________________________________________________
| From: | "Ron Raby" <ronr(at)advanceddesign.com> |
Mike
It happened on the first flight, and the same thing on both radios. PS eng.
allready said they would take it back an check it out. I am just trying to
eliminate anything I may have missed before I send it back
Thanks
Ron Raby
----- Original Message -----
From: "Mike Larkin" <mlas(at)cox.net>
Subject: RE: AeroElectric-List: ptt problem
>
> How long did the system work until it failed or started giving you
> problems? Does the problem happen on both com radios the same way?
>
> If so I think you are on the right track, it sounds like it is the audio
> panel (PMA 7000). Give PS-Engineering a call and see if this is a
> common problem. There are good people at PS-Engineering.
>
> Mike Larkin
>
> -----Original Message-----
> From: owner-aeroelectric-list-server(at)matronics.com
> [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Ron
> Raby
> To: aeroelectric-list(at)matronics.com
> Subject: AeroElectric-List: ptt problem
>
>
>
> To everyone:
>
> I am having a problem with my push to talk on the pilot side. On the
> ground
> and for a while during flight the push to talk works fine. It then stops
>
> working. The copilot side works fine. The parts involved are the PS
> engineering pma 7000, approach systems hub, approach system cables,
> Garmin
> 530 and an SL30.
>
> I have rang out the cables directly up to the pma 7000. I cannot find a
> problem. I have rang out the switch both when it is working and not and
> it
> is ok. I have shut of the intercom during flight and it still does not
> work.
> my gut feeling is something is not working in the pma 7000 when it gets
> warm. Ideas would be appreciated.
>
> Thanks
>
> Ron Raby
>
> Lancair ES
> flying
>
________________________________________________________________________________
| From: | "Jerry Grimmonpre" <jerry(at)mc.net> |
Eric Ruttan ...
You seem to be on to something here and the tone of your note is solid and
well meaning ... what is the message the reader should capture?
Confused in Illinois ...
Jerry Grimmonpre
----- Original Message -----
From: "Eric Ruttan" <ericruttan(at)chartermi.net>
Subject: AeroElectric-List: Dear Bob;
>
>
> Dear Mr. Nuckolls;
>
> Last time I commented on this topic a very well known engineer ran away
> and
> did not come back for months. I do not desire a repeat of that but I
> think
> there are some problems that have not been addressed.
>
> It is with deep personal respect for your thinking process and work ethic
> I
> send these comments.
>
> From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
>
>> .pdf's are most acceptable but I'll work with crayon on toilet paper
>> if necessary. If you're offering the next greatest thing, let's get
>> it out there for folks to exploit. I've hidden nothing, you've
>> revealed nothing.
>>
>> Bob . . .
>
> "I've hidden nothing, you've revealed nothing."
> This is the single point I have perceived from the very beginning of this
> discussion months ago. Claims are made. Ideas are shouted. But not a
> single simple idea critique has been proposed. Not a single, real world,
> valid critique, of any Z diagram has been made. Not single actually
> verifiable experiment or test has been shown in support of this
> "critique".
> In fact you have done experiments in response to these vague claims to
> quantify an area of these vague claims as not valid.
>
> Bob, at what point do you stop repeating yourself and realize your request
> for clarification is not being addressed? At what point to you stop doing
> work to disprove or quantify accusers unsupported and vague claims? When
> should they be responsible for SUPPORTING data behind a critique, OR EVEN
> CLEARLY ARTICULATING said critique?
>
>> And you've probably discovered, it's very USEFUL to have
>> conversations
>> with others who understand the role of good critical design review .
>> .
>> . they
>> are invaluable resources for thinking EVERYTHING trough. It's a
> win-win
>> . . .
>> either good ideas are deduced as sound and bad ideas are prevented
> from
>> going into production.
>
> I totally agree in the value of peer review. Bob, let me humbly suggest
> this is not what is happening here. What I see is a vague and changing
> critique of a well proven design. I see no clear articulation of simple
> ideas or raw data to suggest we can even begin to determine what the
> critique is. How can a discussion occur when peer reviewer will not
> clarify
> to a "simple idea" the critique? I see you, Bob, having a discussion with
> what you think they mean. I see you building an experiment showing an
> entire area of these vague claims are not supported in your experiments.
>
> The response to your experiment was to ask about parts, not get into the
> lab
> and repeat it. Bob, what does that mean to you? It holds great meaning
> for
> me.
>
>> > Chin up Bob.
>>
>> Thank you. This isn't a battle to be won or lost. It's an arena of
> ideas
>> wherein every idea should be evaluated for suitability to task.
>
> In your world it is an arena of ideas. But you are in the arena with
> someone who wont share/talk about/quantify ideas. If that is true, and it
> may not be, then I suggest you question your premise about where you are.
>
>> The hard
>> part is defining "task" and "suitability" in real numbers and failure
>> mode effects analysis and then fitting that to the marketplace.
>
> Bob, task is not hard. This "peer" discussion has refused to even
> addressed
> task.
>
> I cut your response to Eric's post. It also takes us down the same path.
> Eric is a very bright guy. He knows that saying "I would do this" is
> useless. It is the "because" that matters, which for some reason is
> missing
> from his post.
>
> Again I thank you for your time.
> Eric
________________________________________________________________________________
| From: | "Dan Checkoway" <dan(at)rvproject.com> |
| Subject: | Day/Night mode for Digitrak or Pictorial Pilot |
If you have a Digtrak or Pictorial Pilot, you might find this
interesting...if not, delete!
When I installed my Digitrak a while back, I wired it into my panel lights
dimmer. This was a mistake. The only usable setting at night in my opinion
is the DIMMEST setting. Any brighter than that and the LED display gets way
too bright. In my case, hooked to my panel lights dimmer, as I brightened
the panel, the Digitrak's display was really distracting (too bright).
The Digitrak and Pictorial Pilot really need an "inverse" dimmer (dim at
night, bright during the day). But that's way too complicated for me.
I recently installed the Pictorial Pilot (same exact wiring/connector), and
I finally got around to fixing this problem. My "solution" is really simple
and super cheap.
http://www.rvproject.com/20050329.html
I wired up a mini-toggle switch ("Day/Night"). In the "Day" position, the
wire is not connected, and the display is full bright. In the "Night"
position it gets +12V through a 22k resistor, and it's about as dim as
possible. I've flown at night with this and it is muuuuch better.
Anyway, I wanted to spread the word that a 22k resistor will do the trick
for minimum brightness. Current consumption is almost nil, so the resistor
rating doesn't even matter imho. I used a Radio Crack special.
Hope this helps,
)_( Dan
RV-7 N714D
http://www.rvproject.com
________________________________________________________________________________
| From: | "David E. Nelson" <david.nelson(at)pobox.com> |
| Subject: | Re: Day/Night mode for Digitrak or Pictorial |
Pilot
04/04/2005 01:56:04 PM,
Serialize by Router on MailServ58-US/AUS/H/NIC(Release 6.5.1|January 21,
2004) at
04/04/2005 01:56:06 PM,
Serialize complete at 04/04/2005 01:56:06 PM
Sounds like a good application for a photocell/photoresistor to negate the
switch. Looks like RadShack has them listed as 'CdS Photoresistor Mukti Pak'
(276-1657). They don't advertise the resistive ranges but that can be fixed.
/\/elson
On Mon, 4 Apr 2005, Dan Checkoway wrote:
>
> If you have a Digtrak or Pictorial Pilot, you might find this
> interesting...if not, delete!
>
> When I installed my Digitrak a while back, I wired it into my panel lights
> dimmer. This was a mistake. The only usable setting at night in my opinion
> is the DIMMEST setting. Any brighter than that and the LED display gets way
> too bright. In my case, hooked to my panel lights dimmer, as I brightened
> the panel, the Digitrak's display was really distracting (too bright).
>
> The Digitrak and Pictorial Pilot really need an "inverse" dimmer (dim at
> night, bright during the day). But that's way too complicated for me.
>
> I recently installed the Pictorial Pilot (same exact wiring/connector), and
> I finally got around to fixing this problem. My "solution" is really simple
> and super cheap.
>
> http://www.rvproject.com/20050329.html
>
> I wired up a mini-toggle switch ("Day/Night"). In the "Day" position, the
> wire is not connected, and the display is full bright. In the "Night"
> position it gets +12V through a 22k resistor, and it's about as dim as
> possible. I've flown at night with this and it is muuuuch better.
>
> Anyway, I wanted to spread the word that a 22k resistor will do the trick
> for minimum brightness. Current consumption is almost nil, so the resistor
> rating doesn't even matter imho. I used a Radio Crack special.
>
> Hope this helps,
> )_( Dan
> RV-7 N714D
> http://www.rvproject.com
>
>
--
~~ ** ~~ If you didn't learn anything when you broke it the 1st ~~ ** ~~
time, then break it again.
________________________________________________________________________________
| From: | "Paul Messinger" <paulm(at)olypen.com> |
| Subject: | Re: Fresh approach |
----- Original Message -----
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: AeroElectric-List: Re: Fresh approach
>
>
>
>>
> or complex?
>
>>The more
>>complex the design the more likely of failure and or improper pilot usage.
>>Having a "after failure of the alternator" multipart reconfiguration check
>>list is not a good idea in my opinion (as I recall Bob's design needs up
>>to
>>6 steps to reconfigure for emergency ops).
>
> Absolute BS Paul. Describe your perceived emergency checklist for
> emergency ops on ANY system described in the 'Connection . . . no,
> let's limit it to Z-13. If a low voltage light comes on, what is
> your perception of pilot response that take more than three steps?
I got the long list of steps from a post you made last fall discussing the
switching process when the alternator failed and it was necessary to turn
off things and switch to the emergency??? bus that is directly connected to
the battery. It was 5-6 steps as I recall. Its not worth it to me to go back
and pull the post out of the archives. NO BS but so what??
You said it, and others remember but so what? ANY check list is too much. I
am finishing the design of a system that requires NO action by the pilot. If
the battery fuel gauge says he has enough battery fuel with the current load
to get to a safe airport. Then the pilot can take optional actions to extend
the range and immediately see the results of turning things on or off. If
the pilot has tested the batteries and has installed quality batteries he
will have plenty of time to make decisions.
In your system there is NO means to tell how long you have on batteries
except trust as even the minimal current meter is not included.
You say use any battery but I have one of the "any" batteries that lost 2/3
of its AH in 2 years. If the pilot was counting on that battery he would
only have 1/3 the flight time left he was counting on. I think that is
unacceptable. You say to simple never check the battery AH and simply
replace the primary battery annually and take the one year old unchecked
battery and use it for the backup battery. Now we have a new but untested
battery in primary and a used untested battery in the backup position. I
have a sample of one where a 2 year old battery of that class having lost
2/3 of its AH. How much did it loose at the end of one year? Who knows. The
point is there is no way to tell what is left and clearly at 23 months and
28 days you may have far less ah than expect or need. With no way be sure
how fast you are now draining the batteries its possible you can end short
of the runway. I know of many cases of this on auto engine conversions. Sure
its important to be alerted that the alternator has failed but then its
critical to know how long you have left to fly. NONE of your designs and
recommendations supports knowing, they all are based on trust.
> You pushed aside a DEMONSTRATED current limit of under 260 amps for
> a crowbar event and insisted that events in the 400A to 700A range
> exist. Tell me how to duplicate your measurement or drop it.
I have posted at least twice the details of my test that resulted in 400
amps.
If you took the time to do a worst case analysis you would see that how it
is possible that more than 400 amps can occur.
I repeat for the third time! My battery setup was dual PC625 with a combined
internal resistance of 3.5 milliohms. My CB has a measured resistance of 10
milliohms ( the CB spec only specifies the max not the min and I have 3 that
range from 10-12 milliohms) I have approx 4 ft of #4 and 5 ft of #6 wire to
and from the CB and local ground ( I would have to go and measure exactly
but its copper lugs to copper lugs except at the battery where its brass to
copper. The CB buss is a bussbar connected to the #6 wire. Your OVP module
has 1" leads as its directly across the CB. ALL bolted connections. (Short
circuit battery current greater than 3600 amps).
Bottom line is that any test or even 100 different tests will never
determine the possible range of results.
> You make statements that ARE YET to be described in any repeatable
> experiment
Pure BS as you say. That you have not run my test with my specific parts IN
NO WAY MEANS THE TEST IS NOT REPEATABLE.
Perhaps I do not understand your definition of repeatable? Surely you do not
mean any 5 amp CB will give the same results. In collage we had experiments
and each set of equipment was identified as part of a specific set and in
that case the results were repeatable but varied quite a lot from one
students kit to another When you wrote up the lab report it was critical you
includes the kit serial number.
Your experiment is repeatable but change your batty or change the wiring or
the CB and you will get different results that are repeatable with that
specific configuration
MY tests was run dozens of times and witnessed others including my peers who
were able to properly evaluate the setup. The equipment was Tektronix in
calibration. That you have not seen that test is not relevant. I did not see
your test but I respect your data as you should respect mine but that seems
to be a fantasy.
yet you push aside my fully described and published experiment
> by claiming that I have made some conclusion based on a single test which
> represents no type of engineering you respect. This was in spite of the
> fact that no conclusion was made. I did the work, gathered the data,
> hypothesized a 250A max limit (installed systems run much lower) and
> you have yet to tell me where that experiments was bad . . . respectable
> or otherwise.
More BS facts not in evidence. My test was directly modeled from the wiring
in MY aircraft.
You did make a conclusion and even in this post you say that installed
systems run much lower. How can any person believe that? How many installed
systems have you looked at and measured?? Surely not mine where I used good
engineering methods to reduce the wiring voltage drops to the CB panel.
If you would do a worst case analysis using all possible part variations you
would see how easy it is to get 400 amps. Use my battery, wiring and CB
resistances its not hard to run the numbers.
Lets see, I measured under 0.020 ohms battery + to battery - (that is actual
not the estimated listed above wiring and CB in series). So if the battery
terminal voltage under load dropped to 8 V that makes the load current 400
amps. Perhaps that is maximum possible but my having 3 CB's in the 10-12
milliohm range is that the absolute minimum resistance? The actual battery
internal resistance is not specified just that the short circuit current is
specified to be greater than 3600 amps in this example of 2 in parallel.
Math department. External battery load resistance (measured) 0.020 ohms. 400
amps current V=IR so 0.020 x 400 = 8 V battery terminal minimum required.
Actual battery terminal voltage was higher indicating the real internal
resistance was lower than the nominal value specified.
I mentioned I had one non repeatable 700+ amp test in a different
configuration. That test was not something I repeated as it was not a
reasonable wiring configuration but the 400 amp case was.
BUT so what even 200 amps is out of line with good engineering practices and
not necessary with the addition of a series resistor or a different approach
to opening the "B" lead.
I guess your definition of repeatable test is different from mine. The test
is repeatable only if the same identical parts are used. Not the same part
numbers, the identical parts. If I shipped to you my complete test you would
find it repeatable
>
>>Why worry about faults that are as likely as prop bolt failures?
Exactly and I suggest that a hard failure of the alternator field is very
rare. Breaking the "B" lead in that case may weld the contacts on opening
and you end up with no separation of the alternator. If the regulator
failure is simply HI output the current/voltage is controlled and the
voltage across the contacts are lower and the opening arc is very likely to
simply go out.
I know of no testing where the field is connected directly to the "B" lead
and then the load and rpm is varied to see what any specific alternator
does. While such testing might give us a general idea of what happens its
not valid to conclude that all alternators will perform the same way and as
we use different brands the results will even less indicative or what might
happen.
As above I have shown that battery voltage can be 8 v and that can be what
the "B" lead sees during the OVP event depending on how the wiring is
physically connected. The voltage at the CB is thru mostly different wiring
that the "B" lead wiring so V drops to the CB are not the same.
8 V is more than enough when you consider the alternator field is directly
connected internally to the alternator to the "B" lead. With a shorted to
ground regulator that puts full voltage to the field and soon as the OVP
event trips the CB the OVP load is removed and immediately the alternator
output V is only held down by the battery while the slow opening of the "B"
lead contactor is in process. Given your test with a 15 ms OVP CB opening
and the contactors opening time of 50 ms (with a diode across it) there is
plenty of time for the alternator to recover and make contact opening a
firey event. If I can remember you stated that you were not sure the
contactor contacts could take it. On that WE agree.
The failure of the internal regulator in a hard short mode which results in
the burnout of the alternator is exceedingly rare. I only have heard of one
in the last 20 years and none were ever noted by local alternator and auto
shop personnel. Its extremely rare, just that if it happened it can be bad
news. But so can a prop failure which is reported much more often. Failing a
little high is the second most common failure as the failure of no output is
99+% of the failures reported locally.
Do we know if any failed high but not shorted outputs loose control of the
field control??
Perhaps its a simple opening of the field control lead is all that is
needed.
The simple alternator regulator going a little high and the OVP tripping is
a very different failure mode that is much easier to deal with. AN OVP trip
may or may not even be the result of a failure. It could simply be a false
trip. I and others have been told by dozens of builders that they have
scrapped the OVP module because of false tripping. AS you agreed its
possible to false trip simply from excessive contact bounce when switching a
heavy load as I found in the Load dump testing (Yes you agreed in one post
here) where the false trip was 100% of the time until I added a large
capacitor across the OVP 10 mfd was not enough and I ended up with 1000 mfd
to eliminate false tripping. The OVP still worked as I would have expected
it to but only in the case of true OV. Any OVP module we install on the
aircraft must NOT false trip. Its easy to design one that does not false
trip and one that does not crowbar with large currents (two different
concepts).
If you review experimental prop failures you will find prop bolt failure
(not fracture as much as loosening) has killed people. In one case it was a
family of 4.
The feedback in
> received from you has only generated a need to address your concerns
> by going to the manufacturers and other spec sources.
I am only pointing out over and over that designs need to be done with
respect to the specifications as a parts ratings are not determined by test
and ignoring (or overlooking a limitation in the data sheets).
In the engineering world I come from the engineer that designed the circuit
must defend it. You have turned it around and said prove me wrong. You have
simply gotten it backwards. I say your OVP design as a module its self over
stresses parts when installed in a possible aircraft configuration. Its up
to you to show its not possible to overstress it.
But clearly that is never going to happen.
Perhaps you can show us ANY case where the crow bar approach has been used
to directly short a large battery supply. I have found no such application
and all my peers have never heard of one either. Its simply a misapplication
that my peers all agree on. The crow bar has its place but no one I know has
ever seen it used this way.
I am going to respond to a few previous incorrect statements you have made
about me but if you truly want to stop this exchange simply stop your
replies. I will not continue the debate over things like the "need to design
within the specifications" and "worst case analysis" as clearly we do not
agree and its confusing the rest of the list. Also your OVP is off limits by
me from future posts. We will never agree.
Paul
________________________________________________________________________________
| From: | "Paul Messinger" <paulm(at)olypen.com> |
| Subject: | Well Bob you win |
I cannot continue to spend the time when its clear we have such different
backgrounds and backgrounds of experience. There is simply no common ground
to a discussion.
In aerospace, "failure was not an option" so every design was subjected to a
detailed design review and the review package included a worst case design
analysis as well as a proof of concept, sample of one lab test. Design
approval was based on the worst case analysis demonstrating all component
variations resulted in parts stress of less that specified maximum so any
combination of parts would work and not be overstressed. Or even work as its
possible to have a single lab test work and production parts when assembled
fail to work. Happens more than some might think.
I have tried to reason and for a while I thought you were considering my
facts but that moment of sanity has past and you are back in the old mode
Bob is so famous for.
Just as one cannot test reliability in to a product:
You cannot test a bad design into a good one.
You cannot sample the population with one sample and get meaningful results
etc etc.
This is the only place where a single test is suffient to justify the design
is good.
I have never experienced a case where the designer not only had never done a
worst case analysis but clearly had no intention of doing so. This is based
on a partial worst case analysis I performed showing any part combination
would not work.
We have gotten into a debate and lately you have resorted to name calling to
the extent most of the list readers are confused and the original facts are
buried in reply's to reply's.
I have many more relevant things to bring up that potentially can effect how
OBAM aircraft are electrically wired but its clear that I am wasting my
time.
I have a real contract with a real player in the experimental engine market
to advance the state of the art. That is where I will be spending my time as
our debating is a huge waste of my time.
For those who may think I am an air head as Bob would like you to believe I
have enough commendations and awards for performance and technical
excellence to paper a hanger door and have paper left over.
How else would I win such a contract for a new generation of aircraft
electrical systems??
I have many posts that need reply's but they will simply not be posted this
is truly the end.
Any who want to ask me something must email directly to me.
Paul
________________________________________________________________________________
| From: | "Paul Messinger" <paulm(at)olypen.com> |
| Subject: | Re: OVP etc - do we have a bottom line? |
----- Original Message -----
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: AeroElectric-List: OVP etc - do we have a bottom line?
>
>
>
>>
>>The CB max no damage current rating is a personal concern to some and not
>>a
>>big deal IF you have a real event as the alternator has failed. replacing
>>the CB may or may not be needed. A purest will replace it most will simply
>>press on by resetting. My objection is it does overstress the CB and a
>>good
>>design of OVP would limit the current so there would be no question.
>
> The data I'm getting so far does not support the "no damage"
> interpretation
> of the specification cited . . . but that's a study in process.
My point is the spec says it may no longer meet spec. It does not say in
what parameters are out of spec. Until the spec is revised with more detail
the engineers I have worked with would never operate the device out of
spec.... To me out of spec clearly means damage. It might mean contact
resistance or lifetime etc but we have no way of knowing and unless the spec
is clarified in writing by the manufacturer we have no choice but to not
violate the spec. As its simple to modify the circuit to meet spec why even
spend the time to get the 3 or 4 manufacturers to clarify in writing what
happens. My guess is you will never get anything in writing beyond perhaps
an engineers opinion.
What is so hard about adding a current limiting resistor? I simply do not
understand your apparent resistance.
The worst thing to happen to current installations is the potential need to
replace the CB in the event of an OV event. If there is a valid OVP event
the owner already needs to replace the alternator so it not that big a deal.
That is on OBAM acft. Certificated aircraft is a different case where I am
being told its mandatory to replace the CB is the LR-3 trips.
>> I have a documented case of
>>certificated aircraft having major compass errors accumulating over time
>>with currents around 50 amps max passing 18" away from the compass so it
>>can
>>be a concern (The mandatory service bulletin to correct this problem will
>>be soon posted here for all to see).
>
> Whoa! Where does that come from? This issue has been addressed
> years ago and improved upon when b-leads were taken out of the
> cockpit and bus bars were moved off the panel into fuse blocks.
> Just about EVERY airplane has a placard saying that the compass
> is calibrated with certain things ON or OFF. There are demonstrated
> concerns and techniques involving wires carrying high static current
> loads since the first generator went into an airplane. So what's that
> have to do with a crowbar ov event? Every time you crank the engine
> you have a 500-1000 amp event, why do we not agonize over that?
Its not the currents, its the location of the wiring. Mooney released a
Mandatory Service Bulletin M20-150A that addressed the need to relocate the
wire feeding the aux CB panel. It even required the elimination of the
remote grounding of the recognition light wiring in the wings by replacing
the single wire grounded at the tip with a twisted pair grounded at the main
ground point. Over kill perhaps but as there were mod kits made available I
suggest the modifications had merit.
We are looking at a gradual increase in the compass error of 30 deg or more.
I know the owner who is a IA who had that happen on his aircraft and had a
30 deg error from the simple over time of the current flowing from the left
to the right side of the panel. The compass was 1/2 way up the windshield.
He complied with the bulletin and the problem has not recurred in 35 years
I am not talking about the need to swing the compass with specific things
ON, this was a permanent change over time from the electric field
magnetizing the steel tube inner structure. The currents were well under 50
amps and had nothing to do with starting. Also this was manual gear aircraft
so there is only the starter and alternator that produce large currents and
with the battery ahead of the firewall there was nothing like you suggest to
generate large currents. All starting and alternator wiring was ahead of the
firewall along with the battery and the specific cause was mostly the wire
from the left side of the panel to the right connecting the main power to
the aux CB panel for things like avionics etc.
My concern is we are now installing avionics that may contain very sensitive
magnetometers and even 50 amps can be a problem. Having a steel tube cockpit
only increases the need to be very careful in wire routing. There are some
popular OBAM acft with steel tubing like the Glastar.
>
> I had to chase a rat out of the woodpile on Bonanza compasses that
> didn't like having the SD-20 alternator turned on . . . on the OTHER
> side of the firewall . . . we went to the alternative compass location
> on the windshield. Yes, every airplane has issues of electrically
> induced magnetics but none of those issues are foundation for
> dismissing the value or utility of a crowbar ov protection system.
>
>
>>If you have a RV with Van's alternator add the recommended Transorbs and
>>consider using Erics OVP approach. If you have the Aeroelectric OVP any
>>false trip is unlikely to be a problem to the alternator with the added
>>Transorbs.
>>
>>There is little probability of problems with the B & C conversion using
>>the
>>LR-3 regulator but adding "B" 'lead transorbs are recommended by both Eric
>>and myself on all alternators.
>>
>>If you have a Glastar or other aircraft with a steel tube inner or outer
>>cabin structure I would NOT use Bob's OVP module simply due to the poor
>>effects of HI currents in the cabin. IE careful wiring and transient
>>currents in the 50 amp or above might be hazardous to your flight
>>instruments and as a minimum a compass accuracy check on an annual basis
>>is
>>recommended.
>
> Unmitigated BS Paul . . .
True (not BS) and see my above comments on the case of Mooney. I am tired of
your comment about BS when you simple do not like the truth or a valid
opinion backed by Facts! I base my comments on industry documents (l have
posted in the past) and it would be nice if you asked for references and not
simply say its BS when its clearly not and I can back it up.
Its widely know that its very easy to magnetize steel and 4130 is no
exception. The small field form a steel tube can and does often effect a
compass a couple of feet away. In this case it was cumulative from currents
over time where the currents were relatively small. Not at all like the
direct effect of current where there is no lasting effect.
There are far too many cases of your simply saying it is BS for me to
continue most any discussion with you given your apparent closed mind. How
about the widespread use of simple diodes across relay coils?? When the
relay industry in the US and Europe (as an example) says that is not the way
to do it. I am sure that I would have gotten a BS comment If I have not
posted proof than the simple diode was not the best way but actually
encouraged contact welding on opening due to the slowing down of the opening
speed. You have often stated that the speed of opening is not slowed once it
starts but industry says you are wrong. Just as you are wrong in saying
diodes are the way to clamp transients across the relay coils. If the coil
was the only concern I might agree but the potential damage to the contacts
is equally important. Thus the relay industry says do not use a simple
diode.
>>In conclusion;
>>
>>There is simply no one size fits all that is safe to use. Most of the
>>builders are safe with the externally regulated LR-3 setup. some will be
>>unsafe with the use of Bob's OVP module and many are in the middle.
>
> How "unsafe" . . . are we talking about hazard to equipment or
> hazard to people?
Hazard to equipment and that may result in hazard to people. If the compass
heading is in error from the above case it can be hazard to people. If the
magnetometer inside a piece of avionics is damaged or the calibration is
shifted it may be hard to detect and expensive to fix.
My point is not necessary to have the large currents. I am mystified why
you insist high currents are OK and not redesign to lower currents.
>
>>However remember any who want to use the emergency mode of "No battery"
>>need
>>to know that both the LR-3 and the OVP module have a 100% chance of
>>tripping
>>the alternator off line with no battery and the often suggested addition
>>of
>>a 25,000 mfd capacitor to "stabilize the alternator regulator is by test
>>not
>>going to prevent false triggering of these devices from such simple things
>>as turning off landing lights or strobes or recognition lights if the
>>alternator is lightly loaded.
>
> I have yet to see any data that shows alternator only operations
> are compatible with the DO-160 suite of aviation products, much less
> those for which you're trying to craft a kinder and gentler electrical
> system. The dynamics of the voltage regulator's servo loop are "tuned"
> with a battery on line. If one desires a regulator optimized for
> no-battery operation, that can be supplied but to the present time,
> no one has asked for it.
Disagree that alternators need a battery. They do need some sort of load to
stabilize the output voltage and there is the load dump to consider and the
solution is simple.
The alternator regulator simply adds current to the field if the load
increases and stops current flow if the voltage is too high. There is no was
for a regulator to stop load dumps as the regulator has no control of the
output other than cutting field current. redesign of a regulator to clamp
load dumps is not a minor change as the regulator would need control of the
output side of the alternator which it currently does not have. But the
addition of proper transorbs is a simple thing to add to clamp the load dump
and VOLA you have a setup that does not need a battery for stable operation
Or at least the popular ND brand
This is not theory as flight tests have been made with no transorbs no OVP
crowbar and no capacitor. Flight testing including load dumps from landing
light cycling and no damage to any component. Not that this should be done
with out transorbs in normal operation but its a flight test of a real
aircraft as you seem to desire. (55 amp ND rebuilt alternator by Bosch as
the rebuilder).
Its been demonstrated many times that a 25,000 cap does filter much of the
load dump and acts as a ripple filter for the alternators switching
regulator. Its also been demonstrated that no cap will work IF you control
the load dumps with Transorbs. In fact you do not need the capacitor if you
have properly added transorbs.
The problem is the use of a quick acting OVP as in the LR-3 or the OVP
module is they cannot tell the difference between a load dump and a
regulator failure and that is why they need a battery. Thus my statement
that no battery operations is prevented if these or a similar fast acting
OVP is in the system, The use of a 25,000 mfd capacitor does not keep the
Voltage under the 16.x volts so the OVP trips. Eric and I have demonstrated
by test and analysis that a 200 MS delay in the OVP along with the use of
transorbs allows no battery operation while insuring a legitimate failure is
detected and action taken
>
>
>>No battery operation is my opinion a very important emergency mode of
>>operation.
>>
>>Here is what Bob has recently stated on this subject "but the question of
>>no-battery operation has never been addressed nor recommended in any of my
>>writings"
>>
>>I agree that none of his suggested schematic designs allow this mode
>>simply
>>because they all include a LR-3 or OVP module that triggers with a load
>>sump
>>(that Bob requires the battery to clamp).
>
> That was not the consideration at the the time. NOBODY but Barons
> and Bonanzas allows battery-less operation by manipulation of
> panel controls. There was a good reason for that long before the
> manner and style of ov protection was considered. To imply that
> I don't recommend battery-less operation just to satisfy some
> feature of the ov protection system is a presumption of facts
> not in evidence and patently untrue . . . I was there. I did it
> and I know the foundation upon which the system was built.
I know and certificated aircraft are not the issue here. I do not think they
ever were given the ability to change the basic electrical design under the
FAA regulations including batteries. Also what has been done in the past in
not at issue. Past times the engine ran fine with no electrons needed.
Today (and to for over 10 years) we have the need in some cases for large
currents (10-20 amps) to keep the engine running. I object to the lack of
the Aeroelectric connection not recognizing this and supporting this
emerging use of electrically dependent engines There are thousands of auto
conversions flying today and this is not new as the numbers have been
growing over the last 15 years. This is nearly always a OBAM aircraft and
yet today there is no electrical system design that meets that need
properly.
>
>
>> No battery, no clamp, first event
>>and alternator trips off line and no electrical power.
>
> Neither the LR-3 nor the OVM-14 was designed to accommodate the
> battery-less system. They COULD be . . . the first question that needs
> to be address is whether battery-less operations are broadly practical
> and therefore recommendable. If that proves to be useful, a suitable
> regulator and ov protection system can be designed for that service.
> Please don't imply that the products presently offered are somehow
> evil because they don't meet requirements not in place when those
> components were designed.
I have demonstrated by test and others have demonstrate by flight that
current alternator regulators will work properly with the use of load dump
controls WE do not need a new type of alternator regulator just a load dump
control (extremely simple) and a different type of OVP (commercially
available right now from Eric Jones and its been tested to verify it truly
works)
>
> If your suggesting a new environment, get it out there on paper
> and let's explore the numbers. See my other posting.
Nothing beyond what I have already posted. Add load dump control and a time
delay OVP and you are there; Both are a matched set as the Load dump
transorbs need to be matched to the alternator so they are not overloaded by
the end of the OVP time out (if the failure is real and not a simple load
dump).
Tested extensively and backed up with analysis. As you often say If you do
not believe me do some analysis and post where I have gone wrong. I have
both analysis and real tests to back up the analysis.
However I have not studied the external regulator approach much as its
easier to go with the flow as internal stock auto alternators are the wave
of the future in OBAM. If I can get a brand new or quality rebuilt
alternator for $200 to $300 why would I even consider the B & C nearly
$1,000 approach. Even more important in the case of away from home failures
the local auto store likely has a replacement in stock (an important
consideration to many). There are at least 5000 OBAM acft flying with
internal regulators and no OVP modules. Foolish perhaps but its hard to
argue with the numbers. No known failure HI reported. Prop bolts anyone??
Paul
________________________________________________________________________________
| From: | "Eric M. Jones" <emjones(at)charter.net> |
| Subject: | Re: RAC Trim noise |
<Gilles.Thesee@ac-grenoble.fr>
>Nevertheless would a capacitor across the trim motor wires improve things ?
> Probably. Try 1000 pf ceramic capacitor across motor leads (white wires).
>Bob,
Gilles,
Even better---open up the case and add a 0.01 uF cap across the two
terminals on the motor. Then a 0.01 uF cap from each terminal to ground (if
available). This is easy to do.
I've never seen anyone discuss changing the motor and/or brushes in the
MAC/RAC trim boxes, but they certainly can't last forever--and when the
motor brushes wear out they make a lot of electrical noise just before
becoming very very quiet.........So don't squash the noise before you find
out if it might be trying to tell you something.
I think in general that unexplained EMI/RFI noises should make one put motor
brushes on the short list of possibilities.
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones(at)charter.net
________________________________________________________________________________
| Subject: | Re: RAC Trim noise |
Eric,
Thank you for responding.
>Even better---open up the case and add a 0.01 uF cap across the two
>terminals on the motor. Then a 0.01 uF cap from each terminal to ground (if
>available). This is easy to do.
>
>
>
Open the case, hmm, my buddy is going to frown upon that...;-) I'll try
to convince him.
>I've never seen anyone discuss changing the motor and/or brushes in the
>MAC/RAC trim boxes, but they certainly can't last forever--and when the
>motor brushes wear out they make a lot of electrical noise just before
>becoming very very quiet.........
>
The trim unit has 17 hours on it since new, and it is seldom used in flight.
Regards,
Gilles
________________________________________________________________________________
Received-SPF: softfail (mta6: domain of transitioning trigo(at)mail.telepac.pt does
not designate 85.138.31.240 as permitted sender) receiver=mta6; client_ip=85.138.31.240;
envelope-from=trigo(at)mail.telepac.pt;
| From: | "Carlos Trigo" <trigo(at)mail.telepac.pt> |
| Subject: | Re: OVP, grounds, resistive loads |
0.60 COMMA_SUBJECT Subject is like 'Re: FDSDS, this is a subject'
AeroElectric-List message posted by: Christopher Stone
.......
2. I am using a single point ground for all grounds per above description. Z-13
shows a firewall ground, instrument ground and avionics ground. I don't see
any reason not to combine all these to a single point. Am I missing something?
3. Pure resistive loads (heater elements)should not be a source of electrical
noise. That said, I am locally grounding the pitot heat and seat heaters. Again,
am I missing anything here?
4. The wire feeding the main bus is shown unprotected. In my ship this is four
feet of AWG 6 that goes from the bat side of the starter contactor to the main
fuse block. I realize that turning off the master turns this off, but a
short to ground along this wire run could be disastrous! Do I need to be concerned?
......
I appeal to the experts of this list to please answer Chris Stone's questions,
because I am also very interested on the answers.
Carlos Trigo
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: OVP etc - do we have a bottom line? |
>
>
>----- Original Message -----
>From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
>To:
>Subject: Re: AeroElectric-List: OVP etc - do we have a bottom line?
>
>
> >
> >
> >
> >>
> >>The CB max no damage current rating is a personal concern to some and not
> >>a
> >>big deal IF you have a real event as the alternator has failed. replacing
> >>the CB may or may not be needed. A purest will replace it most will simply
> >>press on by resetting. My objection is it does overstress the CB and a
> >>good
> >>design of OVP would limit the current so there would be no question.
> >
> > The data I'm getting so far does not support the "no damage"
> > interpretation
> > of the specification cited . . . but that's a study in process.
>
>My point is the spec says it may no longer meet spec. It does not say in
>what parameters are out of spec. Until the spec is revised with more detail
>the engineers I have worked with would never operate the device out of
>spec.... To me out of spec clearly means damage.
. . . not necessarily. Take a 10A switch and operate it at
15A . . . catastrophic damage or reduced service life? Yes,
I see those curves lopped off very neatly at 10X of breaker
rating and the data which says the breaker is rated for so
many killobreaks . . . so suppose I operate it at 15x or even
50x . . . are we talking about catastrophic damage wherein
the device will fail to function or are we shortening service
life? As an component of a system that won't be called upon to
operate more than a few times in the lifetime of the airplane, the
notion of operating a 5A breaker with 200A trip currents and reducing
life from 2500 to say 200 operations doesn't bother me.
> It might mean contact
>resistance or lifetime etc but we have no way of knowing and unless the spec
>is clarified in writing by the manufacturer we have no choice but to not
>violate the spec. As its simple to modify the circuit to meet spec why even
>spend the time to get the 3 or 4 manufacturers to clarify in writing what
>happens. My guess is you will never get anything in writing beyond perhaps
>an engineers opinion.
If I cannot get a clarification in writing, then the spec is useless
and I have to depend on my own verification of that particular feature.
Charles Kettering was mightily castigated for proposing that one
could drag 2 hp out of a .1 hp motor for a few seconds at a time
in order to get an engine started. He was operating the motor way
of out specification for continuous duty cycle on a motor that might
have a .1 hp service life of hundreds of hours. Yes, if he overloaded
the thing for 10 seconds per start and reduced the service life to
10 hours total, that's still 3600 starts for the lifetime of a
BLOWER motor pressed into STARTER service. So while his contemporaries
said it couldn't be done because a starter motor would have to be
a foot in diameter and 2 feet long, he showed how to design for
controlled overloading of a device to achieve a different result.
>What is so hard about adding a current limiting resistor? I simply do not
>understand your apparent resistance.
A goal of my spec for creating the the crowbar ovm in the first
place was to REDUCE field drive voltage to the lowest possible value
even before the breaker opened. We did a lot of testing that showed
the approx 2 volt ON-voltage for the SCR drove toward that goal.
Therefore, for an internally regulated alternator, the commencement
of the shutdown event was not predicated on response time of the circuit
breaker. This feature impressed the folks at Beech a great deal and
we proved through our own and their independent testing that it
generated no electrical events outside the DO-160/Mil-Std-704 envelope
and was imminently certifiable.
When we expanded application of this technology into the internally
regulated world, the crowbar module was no longer able to act directly
on the alternator . . . opening time of the breaker was added to
opening time of the b-lead contactor in a situation where successful
breaking of the b-lead was dependent on the fastest possible response.
So, adding a resistor to pamper a breaker that may not need pampering
drives us away from the original design goals.
>The worst thing to happen to current installations is the potential need to
>replace the CB in the event of an OV event. If there is a valid OVP event
>the owner already needs to replace the alternator so it not that big a deal.
>That is on OBAM acft. Certificated aircraft is a different case where I am
>being told its mandatory to replace the CB is the LR-3 trips.
Find that in writing . . . I've already talked with the gray beards
at RAC, and one of the most capable and informed representativesw
at Eaton/Cutler-Hammer and nobody's ever heard of this requirement.
I can't find in in the FARS or advisory circulars I have.
> >> I have a documented case of
> >>certificated aircraft having major compass errors accumulating over time
> >>with currents around 50 amps max passing 18" away from the compass so it
> >>can
> >>be a concern (The mandatory service bulletin to correct this problem will
> >>be soon posted here for all to see).
> >
> > Whoa! Where does that come from? This issue has been addressed
> > years ago and improved upon when b-leads were taken out of the
> > cockpit and bus bars were moved off the panel into fuse blocks.
> > Just about EVERY airplane has a placard saying that the compass
> > is calibrated with certain things ON or OFF. There are demonstrated
> > concerns and techniques involving wires carrying high static current
> > loads since the first generator went into an airplane. So what's that
> > have to do with a crowbar ov event? Every time you crank the engine
> > you have a 500-1000 amp event, why do we not agonize over that?
>
>Its not the currents, its the location of the wiring. Mooney released a
>Mandatory Service Bulletin M20-150A that addressed the need to relocate the
>wire feeding the aux CB panel. It even required the elimination of the
>remote grounding of the recognition light wiring in the wings by replacing
>the single wire grounded at the tip with a twisted pair grounded at the main
>ground point. Over kill perhaps but as there were mod kits made available I
>suggest the modifications had merit.
Fine . . . do like we've all been doing for years . . . move the wiring.
I'm writing a change request tomorrow morning to move a wire from one
bundle to another in a 30 year old design to reduce a noise issue.
It seems better to figure out how all the big noises and tender ears
can be engineered to co-exist than to suggest that we should never
generate a big noise because it MIGHT injure tender ears.
>We are looking at a gradual increase in the compass error of 30 deg or more.
>I know the owner who is a IA who had that happen on his aircraft and had a
>30 deg error from the simple over time of the current flowing from the left
>to the right side of the panel. The compass was 1/2 way up the windshield.
>He complied with the bulletin and the problem has not recurred in 35 years
>
>I am not talking about the need to swing the compass with specific things
>ON, this was a permanent change over time from the electric field
>magnetizing the steel tube inner structure. The currents were well under 50
>amps and had nothing to do with starting. Also this was manual gear aircraft
>so there is only the starter and alternator that produce large currents and
>with the battery ahead of the firewall there was nothing like you suggest to
>generate large currents. All starting and alternator wiring was ahead of the
>firewall along with the battery and the specific cause was mostly the wire
>from the left side of the panel to the right connecting the main power to
>the aux CB panel for things like avionics etc.
>
>My concern is we are now installing avionics that may contain very sensitive
>magnetometers and even 50 amps can be a problem. Having a steel tube cockpit
>only increases the need to be very careful in wire routing. There are some
>popular OBAM acft with steel tubing like the Glastar.
Magnetometers have classically be placed as far from potential noise
sources as possible . . . out on wing tips, back in the tail cone,
etc. Anyone who puts a magnetometer on or near the panel should
consider his system integration design very carefully. This isn't
a new issue and probability of it becoming an issue is a combination
of poor systems integration.
> >>
> >>If you have a Glastar or other aircraft with a steel tube inner or outer
> >>cabin structure I would NOT use Bob's OVP module simply due to the poor
> >>effects of HI currents in the cabin. IE careful wiring and transient
> >>currents in the 50 amp or above might be hazardous to your flight
> >>instruments and as a minimum a compass accuracy check on an annual basis
> >>is
> >>recommended.
> >
> > Unmitigated BS Paul . . .
>
>True (not BS) and see my above comments on the case of Mooney. I am tired of
>your comment about BS when you simple do not like the truth or a valid
>opinion backed by Facts! I base my comments on industry documents (l have
>posted in the past) and it would be nice if you asked for references and not
>simply say its BS when its clearly not and I can back it up.
>Its widely know that its very easy to magnetize steel and 4130 is no
>exception. The small field form a steel tube can and does often effect a
>compass a couple of feet away. In this case it was cumulative from currents
>over time where the currents were relatively small. Not at all like the
>direct effect of current where there is no lasting effect.
That's why I don't like for folks to ground their tail mounted
batteries to the airframe . . . but connecting the magnetized
fuselage steel and crowbar events as mutually risky to the compass
is a real stretch.
>There are far too many cases of your simply saying it is BS for me to
>continue most any discussion with you given your apparent closed mind. How
>about the widespread use of simple diodes across relay coils?? When the
>relay industry in the US and Europe (as an example) says that is not the way
>to do it. I am sure that I would have gotten a BS comment If I have not
>posted proof than the simple diode was not the best way but actually
>encouraged contact welding on opening due to the slowing down of the opening
>speed. You have often stated that the speed of opening is not slowed once it
>starts but industry says you are wrong. Just as you are wrong in saying
>diodes are the way to clamp transients across the relay coils. If the coil
>was the only concern I might agree but the potential damage to the contacts
>is equally important. Thus the relay industry says do not use a simple
>diode.
>
>
> >>In conclusion;
> >>
> >>There is simply no one size fits all that is safe to use. Most of the
> >>builders are safe with the externally regulated LR-3 setup. some will be
> >>unsafe with the use of Bob's OVP module and many are in the middle.
> >
> > How "unsafe" . . . are we talking about hazard to equipment or
> > hazard to people?
>
>Hazard to equipment and that may result in hazard to people. If the compass
>heading is in error from the above case it can be hazard to people. If the
>magnetometer inside a piece of avionics is damaged or the calibration is
>shifted it may be hard to detect and expensive to fix.
Anyone mouning a magnetometer inside a piece of avionics needs
to attend a really good critical design review to see that he
has not created the hazard you hypothesize. I wouldn't do it,
don't know why anyone else would if they want the best performance.
There's no magnetometers anywhere in the cockpit/cabin of any
airplanes we build.
> My point is not necessary to have the large currents. I am mystified why
>you insist high currents are OK and not redesign to lower currents.
For the reason cited. Letting the breaker operating time
drift upward in the internally regulated ov protection system
allows the alternator to get just that much more head start
on the b-lead contactor. I'm still not sure that the Cole-Hersee/
Stancor contactors will reliably serve in this function
> >
> > I have yet to see any data that shows alternator only operations
> > are compatible with the DO-160 suite of aviation products, much less
> > those for which you're trying to craft a kinder and gentler electrical
> > system. The dynamics of the voltage regulator's servo loop are "tuned"
> > with a battery on line. If one desires a regulator optimized for
> > no-battery operation, that can be supplied but to the present time,
> > no one has asked for it.
>
>Disagree that alternators need a battery. They do need some sort of load to
>stabilize the output voltage and there is the load dump to consider and the
>solution is simple.
>
>The alternator regulator simply adds current to the field if the load
>increases and stops current flow if the voltage is too high. There is no was
>for a regulator to stop load dumps as the regulator has no control of the
>output other than cutting field current. redesign of a regulator to clamp
>load dumps is not a minor change as the regulator would need control of the
>output side of the alternator which it currently does not have. But the
>addition of proper transorbs is a simple thing to add to clamp the load dump
>and VOLA you have a setup that does not need a battery for stable operation
>Or at least the popular ND brand
>
>This is not theory as flight tests have been made with no transorbs no OVP
>crowbar and no capacitor. Flight testing including load dumps from landing
>light cycling and no damage to any component. Not that this should be done
>with out transorbs in normal operation but its a flight test of a real
>aircraft as you seem to desire. (55 amp ND rebuilt alternator by Bosch as
>the rebuilder).
>
>Its been demonstrated many times that a 25,000 cap does filter much of the
>load dump and acts as a ripple filter for the alternators switching
>regulator. Its also been demonstrated that no cap will work IF you control
>the load dumps with Transorbs. In fact you do not need the capacitor if you
>have properly added transorbs.
>
>The problem is the use of a quick acting OVP as in the LR-3 or the OVP
>module is they cannot tell the difference between a load dump and a
>regulator failure and that is why they need a battery. Thus my statement
>that no battery operations is prevented if these or a similar fast acting
>OVP is in the system, The use of a 25,000 mfd capacitor does not keep the
>Voltage under the 16.x volts so the OVP trips. Eric and I have demonstrated
>by test and analysis that a 200 MS delay in the OVP along with the use of
>transorbs allows no battery operation while insuring a legitimate failure is
>detected and action taken . . .
Fine, show me the test data. I'm not saying that it cannot
be done but stories of demonstrations do not replace data
from demonstrations. By the same token, I'm not going to justify
the "over spec" stresses on a circuit breaker by telling you that
"I've done it thousands of times and have yet to kill a breaker."
The 5A field breaker in B&C's test stand was subject to many,
many ov test events for years before it ultimately needed replacing.
Before it died, it was still performing the intended function
to the extent that thousands of alternators and regulators
were run across that stand in their final acceptance tests. Far
more abuse than anything an airplane would do to it.
I'm talking to folks who manufacture breakers then I'll craft an
experiment to demonstrate what I believe to be true. Then I'll invite
anyone to critique that data so that anyone can be sure I'm not
trying to dry-lab an experiment to produce data that pushes an
agenda. The more I look into it, the more convinced I am of our
design decisions 25 years ago when we were qualifying the crowbar
system. Yes, it's rather indelicate but it satisfied numerous
design goals and bypassed problems common to ov relays at that
time.
>
> >
> > That was not the consideration at the the time. NOBODY but Barons
> > and Bonanzas allows battery-less operation by manipulation of
> > panel controls. There was a good reason for that long before the
> > manner and style of ov protection was considered. To imply that
> > I don't recommend battery-less operation just to satisfy some
> > feature of the ov protection system is a presumption of facts
> > not in evidence and patently untrue . . . I was there. I did it
> > and I know the foundation upon which the system was built.
>
>I know and certificated aircraft are not the issue here. I do not think they
>ever were given the ability to change the basic electrical design under the
>FAA regulations including batteries. Also what has been done in the past in
>not at issue. Past times the engine ran fine with no electrons needed.
>
>Today (and to for over 10 years) we have the need in some cases for large
>currents (10-20 amps) to keep the engine running. I object to the lack of
>the Aeroelectric connection not recognizing this and supporting this
>emerging use of electrically dependent engines There are thousands of auto
>conversions flying today and this is not new as the numbers have been
>growing over the last 15 years. This is nearly always a OBAM aircraft and
>yet today there is no electrical system design that meets that need
>properly.
Your objections are duly noted but totally mystifying. I've published
invitations for any and all creative persons to submit anything
they think should be a part of the 'Connection or the website with
only one small caveat . . . be prepared to defend it with a critical
design review.
The fact that I've not covered this information on my own is in
no way a reluctance to do so . . . there are only so many hours
in the day and it just hasn't moved to the front burners. When
you stated that you were going to do the testing and produce
a report on a system friendly to the automotive conversion
engines, I was delighted. But to date, the only thing I've
heard or seen is nit picking on what's wrong with stuff already
in place and nary a whit on what you want to put into Figure Z-21.
>
>
>Tested extensively and backed up with analysis. As you often say If you do
>not believe me do some analysis and post where I have gone wrong. I have
>both analysis and real tests to back up the analysis.
Be delighted to see it.
>However I have not studied the external regulator approach much as its
>easier to go with the flow as internal stock auto alternators are the wave
>of the future in OBAM. If I can get a brand new or quality rebuilt
>alternator for $200 to $300 why would I even consider the B & C nearly
>$1,000 approach. Even more important in the case of away from home failures
>the local auto store likely has a replacement in stock (an important
>consideration to many). There are at least 5000 OBAM acft flying with
>internal regulators and no OVP modules. Foolish perhaps but its hard to
>argue with the numbers. No known failure HI reported. Prop bolts anyone??
Really? Allow me to quote the following exchange from a few years
back at http://aeroelectric.com/articles/spike.pdf
On 4-2-98 he responds and I offer further comments .
. . .
Perhaps you missed the Kitfox alternator failure where
your regulator was installed and the later string of
failures that destroyed thousands of dollars of electronics
with a transient with a good battery installed. Clearly this
set of electronics needed better protection.
I believe you're referring to Peter G.'s experience
flying to Sun-n-Fun last year. Re-reading his post of
March 11th I've confirmed my recollection that he
started out with an LR3 regulator and a non-B&C
alternator suitably modified for compatibility with the
LR3.
An alternator failure en route prompted
replacement of the whole system with an alternator
having a built-in regulator and an OV protection
system that I'm not familiar with. No B&C hardware
was installed when the system smoked his radios.
If you're speaking about another airplane, I'm not
aware of it and would appreciate knowing who the
owner is.
------------------------------------------------
That's you and me talking. Yes, the failures are rare but
they're never pleasant. Peter isn't the only one to have
suffered the condition. If you have recommended alternator/
regulator combinations to recommend, lets include them
in the notes for Figure Z-21. I'm sure that you're not
suggesting that just any internally regulated alternator
will do.
I've published a first crack at Z-21 at:
http://www.aeroelectric.com/PPS/Architecture/Z21K.pdf
Let's mark it up and get the supporting notes crafted.
Here's not only an invitation but a plea to give us
the benefits of your ideas.
Bob . . .
________________________________________________________________________________
| From: | N1deltawhiskey(at)aol.com |
In a message dated 04-Apr-05 11:09:27 Pacific Standard Time, jerry(at)mc.net
writes:
Confused in Illinois ...
Jerry Grimmonpre
Jerry,
As you are confused, Paul and his friend have successfully won.
If you were playing poker, would you rather bet on the outcome of a hand
where there was only 1 unknown rather that 5? With all the cards turned up, we
may not necessarily like the hand we have, but we can more safely bet on it than
if all the cards are down.
To be less confused, look a who is holding their cards face down vs. face up.
Doug Windhorn
________________________________________________________________________________
| From: | Dj Merrill <deej(at)thayer.dartmouth.edu> |
| Subject: | Re: Cessna A-510 ignition switch |
Hi all,
Thought I'd post an update on my troubleshooting
in case anyone is interested. Turns out that after
disconnecting the mags from the back of the switch,
the keyswitch tests fine, so that is likely not
the problem.
The rest of this is decidedly non-electrical
in nature, and is probably somewhat off-topic, so please
stop reading if you are not interested... *grin*
I took the cowl off the Glasair and upon initial
inspection could not find anything obviously wrong.
So, throwing caution to the wind I decided to try
to start the engine again (the plane had been sitting
for about 2 weeks at this point since the engine had
died halfway down the runway while landing, throttle at idle).
The engine started right up like it always has, and ran fine.
No stutters, bumps, hiccups, and nothing sounded out of the ordinary.
I ran it up, and at various power settings for about 10 mins.
Hmmmm. I'm still looking for the smoking gun,
but I'm not even smelling the gun powder at this point.
So, let's review, says I. I landed on a rather rough
grass strip, and was bounced around a bit (but not
horribly so). Best I can come up with is:
1) carb ice (although I am fairly sure the carb heat was
on during the pattern descent, as normal).
2) vapor lock (although I am running 100LL, and it was
not a terribly hot day, maybe 50-55F, and I've never had
an instance of vapor lock in the three years I've been
flying it).
3) the bumpy landing bounced the float around in the
carb and caused it to stick, or some cruft in the
bottom of the carb was loosened up, causing the same.
4) The engine stalled for whatever reason being at
low idle, and something in the impulse coupling
stuck in the one mag, which would lot allow the
engine to be restarted (but I can't explain why
it worked 2 weeks later).
So I removed the drain from the bottom of the carb,
and drained the fuel out, and ran some more through it.
I could not find any debris in the fuel, but maybe
it got "sucked through" when I ran the engine.
Okay, put it back in, leak check by turning on the
electric fuel pump. Hey there, why do I have fuel
dripping out of the bottom of the carburator?
With the fuel boost pump on, I am reading about
6-6.5 lbs of fuel pressure, and fuel will drip rapidly
out of the air intake of the carb. I do not believe this
is normal - anyone care to comment? Is the pressure
high enough to force the float valve to open in the carb?
At the moment I am thinking that I have some carb
issues, although the engine seems to run fine now.
I can't seem to come up with any other explanation, though.
-Dj
--
Dj Merrill
deej(at)thayer.dartmouth.edu
"TSA: Totally Screwing Aviation"
________________________________________________________________________________
| Subject: | Well Bob you win |
| From: | "Chuck Jensen" <cjensen(at)dts9000.com> |
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com]On Behalf Of Paul
Messinger
Subject: AeroElectric-List: Well Bob you win
I cannot continue to spend the time when its clear we have such different
backgrounds and backgrounds of experience. There is simply no common ground
to a discussion.
In aerospace, "failure was not an option" so every design was subjected to a
detailed design review and the review package included a worst case design
analysis as well as a proof of concept, sample of one lab test. Design
approval was based on the worst case analysis demonstrating all component
variations resulted in parts stress of less that specified maximum so any
combination of parts would work and not be overstressed. Or even work as its
possible to have a single lab test work and production parts when assembled
fail to work. Happens more than some might think.
I have tried to reason and for a while I thought you were considering my
facts but that moment of sanity has past and you are back in the old mode
Bob is so famous for.
Just as one cannot test reliability in to a product:
You cannot test a bad design into a good one.
You cannot sample the population with one sample and get meaningful results
etc etc.
This is the only place where a single test is suffient to justify the design
is good.
I have never experienced a case where the designer not only had never done a
worst case analysis but clearly had no intention of doing so. This is based
on a partial worst case analysis I performed showing any part combination
would not work.
We have gotten into a debate and lately you have resorted to name calling to
the extent most of the list readers are confused and the original facts are
buried in reply's to reply's.
I have many more relevant things to bring up that potentially can effect how
OBAM aircraft are electrically wired but its clear that I am wasting my
time.
I have a real contract with a real player in the experimental engine market
to advance the state of the art. That is where I will be spending my time as
our debating is a huge waste of my time.
For those who may think I am an air head as Bob would like you to believe I
have enough commendations and awards for performance and technical
excellence to paper a hanger door and have paper left over.
How else would I win such a contract for a new generation of aircraft
electrical systems??
I have many posts that need reply's but they will simply not be posted this
is truly the end.
Any who want to ask me something must email directly to me.
Paul
________________________________________________________________________________
| From: | "Wayne Sweet" <w_sweet(at)comcast.net> |
| Subject: | Re: Cessna A-510 ignition switch |
IMHO, the carb needs attention, such as a complete overhaul, just to be
thorough and complete. Why fuss around when a few $ will probably fix the
problem.
Wayne
----- Original Message -----
From: "Dj Merrill" <deej(at)thayer.dartmouth.edu>
Subject: Re: AeroElectric-List: Cessna A-510 ignition switch
>
>
> Hi all,
> Thought I'd post an update on my troubleshooting
> in case anyone is interested. Turns out that after
> disconnecting the mags from the back of the switch,
> the keyswitch tests fine, so that is likely not
> the problem.
>
> The rest of this is decidedly non-electrical
> in nature, and is probably somewhat off-topic, so please
> stop reading if you are not interested... *grin*
>
> I took the cowl off the Glasair and upon initial
> inspection could not find anything obviously wrong.
> So, throwing caution to the wind I decided to try
> to start the engine again (the plane had been sitting
> for about 2 weeks at this point since the engine had
> died halfway down the runway while landing, throttle at idle).
> The engine started right up like it always has, and ran fine.
> No stutters, bumps, hiccups, and nothing sounded out of the ordinary.
> I ran it up, and at various power settings for about 10 mins.
>
> Hmmmm. I'm still looking for the smoking gun,
> but I'm not even smelling the gun powder at this point.
> So, let's review, says I. I landed on a rather rough
> grass strip, and was bounced around a bit (but not
> horribly so). Best I can come up with is:
>
> 1) carb ice (although I am fairly sure the carb heat was
> on during the pattern descent, as normal).
>
> 2) vapor lock (although I am running 100LL, and it was
> not a terribly hot day, maybe 50-55F, and I've never had
> an instance of vapor lock in the three years I've been
> flying it).
>
> 3) the bumpy landing bounced the float around in the
> carb and caused it to stick, or some cruft in the
> bottom of the carb was loosened up, causing the same.
>
> 4) The engine stalled for whatever reason being at
> low idle, and something in the impulse coupling
> stuck in the one mag, which would lot allow the
> engine to be restarted (but I can't explain why
> it worked 2 weeks later).
>
> So I removed the drain from the bottom of the carb,
> and drained the fuel out, and ran some more through it.
> I could not find any debris in the fuel, but maybe
> it got "sucked through" when I ran the engine.
> Okay, put it back in, leak check by turning on the
> electric fuel pump. Hey there, why do I have fuel
> dripping out of the bottom of the carburator?
>
> With the fuel boost pump on, I am reading about
> 6-6.5 lbs of fuel pressure, and fuel will drip rapidly
> out of the air intake of the carb. I do not believe this
> is normal - anyone care to comment? Is the pressure
> high enough to force the float valve to open in the carb?
>
> At the moment I am thinking that I have some carb
> issues, although the engine seems to run fine now.
> I can't seem to come up with any other explanation, though.
>
> -Dj
>
> --
> Dj Merrill
> deej(at)thayer.dartmouth.edu
>
> "TSA: Totally Screwing Aviation"
>
>
>
________________________________________________________________________________
| Subject: | Re: Well Bob you win |
| From: | "Matt Prather" <mprather(at)spro.net> |
This is an unfortunate conclusion of this part of the discussion. I
suspect that if
all of the players were in the same room together and had a couple of
calculators,
an internet connection and a dry erase board, all of this nonsense could
be sorted
out rather quickly. Start with a good breakfast.. Hungry people do not
think clearly. :)
The internet is a magical thing most of the time, but it is not a perfect
means of
communication. The interactivity is not perfect, and hence it will not
replace face to
face encounters.
Best regards,
Matt-
VE N34RD, C150 N714BK
>
>
> I cannot continue to spend the time when its clear we have such
> different backgrounds and backgrounds of experience. There is simply no
> common ground to a discussion.
>
> In aerospace, "failure was not an option" so every design was subjected
> to a detailed design review and the review package included a worst
> case design analysis as well as a proof of concept, sample of one lab
> test. Design approval was based on the worst case analysis
> demonstrating all component variations resulted in parts stress of less
> that specified maximum so any combination of parts would work and not
> be overstressed. Or even work as its possible to have a single lab test
> work and production parts when assembled fail to work. Happens more
> than some might think.
>
snip
> Any who want to ask me something must email directly to me.
>
> Paul
>
>
________________________________________________________________________________
| From: | "Jerry Grimmonpre" <jerry(at)mc.net> |
Hey Doug ...
Good point.
Along with that analogy, I would declare a misdeal and ask for a new deck of
cards ... the kind with all the Kings smiling!
Jerry Grimmonpre
> Jerry,
>
> As you are confused, Paul and his friend have successfully won.
>
> If you were playing poker, would you rather bet on the outcome of a hand
> where there was only 1 unknown rather that 5? With all the cards turned
> up, we
> may not necessarily like the hand we have, but we can more safely bet on
> it than
> if all the cards are down.
>
> To be less confused, look a who is holding their cards face down vs. face
> up.
>
> Doug Windhorn
________________________________________________________________________________
| From: | "Joe & Jan Connell" <jconnell(at)rconnect.com> |
| Subject: | P-Mag Excess Amps response |
This item forwarded to AeroElectric-List(at)matronics.com
Joe Connell
----- Original Message -----
From: Bob Barrow
Subject: PMag excess amps
Hi Joe, I've been reading the PMag thread with interest because I fancy the PMag
concept...but like everyone else I'm waiting for feedback from early users before
committing.
Anyway a recent post on the Aeroelectric list stated the following:
"From what I understand about the PMag.which I don't own, but may someday.
The generator puts out 12-14V at approx. 1500 RPM, and drops voltage output
as the RPM drops. The PMag & Emag will still make spark at some ridiculous
low number like 5 V. So by generating 5+ V at 800 RPM it is self
sustaining. The deal is - it has no excess voltage that can charge a
battery below 1500 RPM, but it can help in a failed alternator situation
above that RPM. Of course the output would be a very low amperage, and I
wouldn't count on continued flight after an alternator failure."
The above comment seems to imply that above 1500RPM the PMag can assist with battery
charging in the event of a failed alternator. The following is a comment
from Emagair which refutes the above :
Hello Bob:
1. The P-MAG power supply is designed to be as isolated as possible from the aircraft.
There is no provision for exporting excess current.
2. The P-MAG alternator is sized to match the needs of the ignition system. Yes,
the power output of the alternator does increase with rpm, but so does the
demand for spark energy. There is little surplus, regardless of engine speed.
I hope that helps.
Kindest Regards,
Brad Dement
I read Aerolectric posts but I cannot make a posting because I am not a subsciber
(don't want to be because it fills up my email box). So I thought you might
find the above information from Brad Dement interesting....and if so you might
like to post it to the Aeroelectric list because I'm sure others would also
find it interesting.
Regards Bob Barrow
RV7A Melbourne Australia
________________________________________________________________________________
| From: | "n801bh(at)netzero.com" <n801bh(at)NetZero.com> |
| Subject: | Re: Well Bob you win |
In aerospace, "failure was not an option" so every design was
subjected to a
detailed design review and the review package included a worst case design
analysis as well as a proof of concept, sample of one lab test. Design
approval was based on the worst case analysis demonstrating all component
variations resulted in parts stress of less that specified maximum so any
combination of parts would work and not be overstressed. Or even work as its
possible to have a single lab test work and production parts when assembled
fail to work. Happens more than some might think
You don't happen to work at Lycoming in their "certified" crankshaft section do
ya???
They call themselves an aerospace company.....And so far their aerospace cranks
have killed at least 12 people in the last few years. So much for their overstressed
ideas.. The cranks probably looked good on "paper"
Ben Haas
N801BH
www.haaspowerair.com
________________________________________________________________________________
| From: | "Brian Kraut" <brian.kraut(at)engalt.com> |
| Subject: | Zeftronics transistor |
This one supposedly has protection against shorts on the field wire, oh
well. I guess an intermittent short for a long time was just a little too
much.
I did call today and ask for tech support and got someone with an accent. I
guess that was Femmi. He gave me a flat out "no" when I asked for the part
number. Nothing really secret about it since the number was on the part
before it burned up. Guess it is a liability thing.
I can figure out something that will work fine easily enough, it just sure
would be nice if someone had the correct part number though.
Brian Kraut
Engineering Alternatives, Inc.
www.engalt.com
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com]On Behalf Of Robert
L. Nuckolls, III
Subject: Re: AeroElectric-List: Zeftronics transistor
>
>
>I have a Zeftronics R15100 voltage regulator that is blown because the
>previous owner of the plane used a shielded wire on the alternator without
>the shield insulated and it shorted to the field stud on the alternator.
Yup . . . field shorts will take down many regulator designs . . . A
B&C LR-3 uses the crowbar system to shut down the supply and protect the
regulator in case of a field short.
>The TO-220 output transistor is toasted and I can't read the complete part
>number on it. It is a TIP1 something. If I had to take a wild ass guess I
>would say a TIP120 is the most likely candidate, but I want to be sure.
>Does anyone know for sure or know where I can get a schematic?
You might call Zeftronics and ask . . . as for Femmi (assming
he's still there). He might just tell you the part number.
It's a plain vanilla transistor. Get someting good for 5A or more,
80v or more. Try a PNP and operate if from a variable power supply
on the bench using a 10 ohm resistor for a "field" load. 99% sure
this will fix it. I've not seen a practical approach to using an
NPN transistor in that slot on a regulator.
Bob . . .
________________________________________________________________________________
| From: | "Werner Schneider" <glastar(at)gmx.net> |
| Subject: | Re: Looking for a B&C oil pressure switch pinout... |
Bob,
it's in your seminar drawings sheet #20 =(;o)
S = common lead
P = should be open contact (no oil pressure)
I = closed contact (no oil pressure)
I had one of this switches failing and got a replacement with the
Common: COM
Normally Open: NO
Normally Closed: NC
markings, there should be a drwaing included with the switch.
Werner
----- Original Message -----
From: "Robert L. Nuckolls, III pinout..." <b.nuckolls(at)cox.net>
Subject: Re: AeroElectric-List: Looking for a B&C oil pressure switch
pinout...
pinout...
>
>
> >
> >
> >Ok, I got one of the three connector switches. Normally I've seen the
> >connections
> >Marked as C, NC, and NO. On this one they are marked P, S, and I... So.
> >Which ones
> >Are which? w/o pressure, P and S are shorted... But I don't know which
> >one of them
> >Is the "common" lead...
>
> I used to sell that switch and thought I had the data on it but
> can't put my hands on it. Call Tim at B&C.
>
> Bob . . .
>
>
________________________________________________________________________________
| From: | Charlie Kuss <chaztuna(at)adelphia.net> |
| Subject: | Zeftronics transistor |
At 10:08 PM 4/4/2005, you wrote:
>
>
>This one supposedly has protection against shorts on the field wire, oh
>well. I guess an intermittent short for a long time was just a little too
>much.
>
>I did call today and ask for tech support and got someone with an accent. I
>guess that was Femmi. He gave me a flat out "no" when I asked for the part
>number. Nothing really secret about it since the number was on the part
>before it burned up. Guess it is a liability thing.
>
>I can figure out something that will work fine easily enough, it just sure
>would be nice if someone had the correct part number though.
>
>Brian Kraut
>Engineering Alternatives, Inc.
>www.engalt.com
Brian & Listers,
Perhaps another lister with a Zeftronics regulator could obtain the info
you need??
Charlie Kuss
________________________________________________________________________________
| From: | "Fred Mahan" <mahan(at)cfl.rr.com> |
| Subject: | Two independent systems |
Bob and all --
How would you wire an airplane with two complete, independent electrical
systems? The aircraft is a Defiant -- two engines, two batteries, two
alternators, the dashboard goodies split between the two systems. What
I'm looking for is a good way to back up one system with the other,
should one fail. I wouldn't want to carry around the cable that would
allow, say, the front engine to start on the rear battery. Just
interested in a good lashup that would allow one system to run
everything in a pinch while in flight. Which diagram would I start
with, and how would I modify it? What would I need to isolate in the
failed system? Or would I just use a switch to connect the two systems?
The two systems do share a common aircraft ground. Thanks!
Fred
________________________________________________________________________________
| From: | Jay Brinkmeyer <jaybrinkmeyer(at)yahoo.com> |
| Subject: | Well Bob you win |
Whatever. You both need a timeout, so take it offline or arrange a dual or
something to spare the rest of us.
Jay
From: "Paul Messinger" <paulm(at)olypen.com>
Subject: AeroElectric-List: Well Bob you win
I cannot continue to spend the time when its clear we have such different
backgrounds and backgrounds of experience. There is simply no common ground
to a discussion.
... snip, and deposit in trash...
__________________________________
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Two independent systems |
>
>Bob and all --
>
>How would you wire an airplane with two complete, independent electrical
>systems? The aircraft is a Defiant -- two engines, two batteries, two
>alternators, the dashboard goodies split between the two systems. What
>I'm looking for is a good way to back up one system with the other,
>should one fail. I wouldn't want to carry around the cable that would
>allow, say, the front engine to start on the rear battery. Just
>interested in a good lashup that would allow one system to run
>everything in a pinch while in flight. Which diagram would I start
>with, and how would I modify it? What would I need to isolate in the
>failed system? Or would I just use a switch to connect the two systems?
>The two systems do share a common aircraft ground. Thanks!
See figure Z-14.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: P-Mag Excess Amps response |
>
>
>
>Hello Bob:
>
>1. The P-MAG power supply is designed to be as isolated as possible from
>the aircraft. There is no provision for exporting excess current.
>
>2. The P-MAG alternator is sized to match the needs of the ignition
>system. Yes, the power output of the alternator does increase with rpm,
>but so does the demand for spark energy. There is little surplus,
>regardless of engine speed.
>
>I hope that helps.
>
>Kindest Regards,
>
>Brad Dement
>
>
>I read Aerolectric posts but I cannot make a posting because I am not a
>subsciber (don't want to be because it fills up my email box). So I
>thought you might find the above information from Brad Dement
>interesting....and if so you might like to post it to the Aeroelectric
>list because I'm sure others would also find it interesting.
Bob, thanks for posting this. I'm surprised that anyone
was thinking that p-mags were designed or intended to
power any ship's systems other than the ignition system
in that p-mag only.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: OVP, grounds, resistive loads |
>
>
>
>AeroElectric-List message posted by: Christopher Stone
>
>
>.......
>
>2. I am using a single point ground for all grounds per above
>description. Z-13 shows a firewall ground, instrument ground and avionics
>ground. I don't see any reason not to combine all these to a single
>point. Am I missing something?
The single point ground block on the firewall is the recommended
minimum number of ground locations. If you want to run everything
there it would be okay . . . but be sure to read the new chapter 18
on audio systems going to press this week. It offers options and
a rationale for selecting them.
>3. Pure resistive loads (heater elements)should not be a source of
>electrical noise. That said, I am locally grounding the pitot heat and
>seat heaters. Again, am I missing anything here?
Nope.
>4. The wire feeding the main bus is shown unprotected. In my ship this
>is four feet of AWG 6 that goes from the bat side of the starter contactor
>to the main fuse block. I realize that turning off the master turns
>this off, but a short to ground along this wire run could be
>disastrous! Do I need to be concerned?
This is an excellent example of designing for the worst case
analysis and then trimming away some actions based on
statistical and practical realities. FARs have relieved
certified aircraft designers from having to protect those
leads electrically because they're easy to protect mechanically
and are extremely unlikely to participate in a hard fault. For
example FAR 23 states:
Sec. 23.1357 Circuit protective devices.
(a) Protective devices, such as fuses or circuit breakers, must be
installed in all electrical circuits other than--
(1) Main circuits of starter motors used during starting only; and
(2) Circuits in which no hazard is presented by their omission.
>......
>I appeal to the experts of this list to please answer Chris Stone's
>questions, because I am also very interested on the answers.
The wires under discussion are easy to install with attention
to mechanical prevention of hard faults.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> pinout... |
| Subject: | Re: Looking for a B&C oil pressure switch |
pinout...
pinout...
>
> >>they are marked P, S, and I...<<
>
>Interesting...on the B&C website, the picture of that switch shows the
>same terminology, but when clicking on the wiring diagram for it, it
>shows, as you said, NC, NO and C!
>
>If you do contact Tim, suggest that they change the wiring diagram!
>
>Anyway, it sounds like you have a meter or a continuity device of some
>kind to be able to determine that P and S are continuous with no
>pressure, so one of them must be the common, and the other is the NC
>terminal.
>
>To determine which, I'd just put about 10 pounds of air pressure on it,
>while having my meter leads connected to I and S, then again with I and
>P...whichever one gives you continuity, is the common. And of course, there
>is the NO lead.
>
>Harley Dixon
The repeatable experiment that yields data upon which good decisions
can be made . . . good idea!
Bob . . .
________________________________________________________________________________
| From: | BobsV35B(at)aol.com |
| Subject: | Re: Two independent systems |
In a message dated 4/5/2005 9:57:44 A.M. Central Standard Time,
mahan(at)cfl.rr.com writes:
Bob and all --
How would you wire an airplane with two complete, independent electrical
systems? The aircraft is a Defiant -- two engines, two batteries, two
alternators, the dashboard goodies split between the two systems. What
I'm looking for is a good way to back up one system with the other,
should one fail. I wouldn't want to carry around the cable that would
allow, say, the front engine to start on the rear battery. Just
interested in a good lashup that would allow one system to run
everything in a pinch while in flight. Which diagram would I start
with, and how would I modify it? What would I need to isolate in the
failed system? Or would I just use a switch to connect the two systems?
The two systems do share a common aircraft ground. Thanks!
Fred
Good Morning Fred,
Different Bob here and one who has very little knowledge of such things, but
I do remember early twin engine certificated airplanes that had dual
electrical systems.
Some of them had single pole double throw switches installed in such a
manner that the power could come from one or the other of the systems.
No interconnection was ever involved. Seemed to work reasonably well.
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
Stearman N3977A
Brookeridge Airpark LL22
Downers Grove, IL 60516
630 985-8502
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Two independent systems |
>
>
>In a message dated 4/5/2005 9:57:44 A.M. Central Standard Time,
>mahan(at)cfl.rr.com writes:
>
>Bob and all --
>
>How would you wire an airplane with two complete, independent electrical
>systems? The aircraft is a Defiant -- two engines, two batteries, two
>alternators, the dashboard goodies split between the two systems. What
>I'm looking for is a good way to back up one system with the other,
>should one fail. I wouldn't want to carry around the cable that would
>allow, say, the front engine to start on the rear battery. Just
>interested in a good lashup that would allow one system to run
>everything in a pinch while in flight. Which diagram would I start
>with, and how would I modify it? What would I need to isolate in the
>failed system? Or would I just use a switch to connect the two systems?
>The two systems do share a common aircraft ground. Thanks!
>
>Fred
>
>
>Good Morning Fred,
>
>Different Bob here and one who has very little knowledge of such things, but
>I do remember early twin engine certificated airplanes that had dual
>electrical systems.
>
>Some of them had single pole double throw switches installed in such a
>manner that the power could come from one or the other of the systems.
>
>No interconnection was ever involved. Seemed to work reasonably well.
Interesting! Can you recall a model? My hands on experience with
the Wichita crop of spam cans is limited and dates back to my
days of working production jobs in the 60's. I don't think anything
we did here offered total redundancy . . . in fact, our BIG emphasis
was accurately paralleling two generators (and later alternators)
to share the loads while driving a single battery and bus. I'd
be interested in knowing the history of any alternatives to that
philosophy in certified ships.
Bob . . .
________________________________________________________________________________
| From: | BobsV35B(at)aol.com |
| Subject: | Re: Two independent systems |
In a message dated 4/5/2005 12:07:30 P.M. Central Standard Time,
b.nuckolls(at)cox.net writes:
Interesting! Can you recall a model? My hands on experience with
the Wichita crop of spam cans is limited and dates back to my
days of working production jobs in the 60's. I don't think anything
we did here offered total redundancy . . . in fact, our BIG emphasis
was accurately paralleling two generators (and later alternators)
to share the loads while driving a single battery and bus. I'd
be interested in knowing the history of any alternatives to that
philosophy in certified ships.
Bob . . .
Good Afternoon Bob,
It was back when I was a line boy (1945/46) and occasional shop flunky.
Later on, I went into the USMC and was trained as an Aviation Electricians Mate
(That meant I got to change batteries and light bulbs. Anything more serious
was sent to A&R (Assembly and Repair))
While in AME school, I was introduced to the intricacies of balancing the
generators via the carbon pile voltage regulators. That brought back memories
of the airplane I had seen that had the isolated systems with transfer
switches for certain components.
In the far recesses of my mind, I think the airplane was one that preceded
the ones you are now working on, the very early Beech 18. It could have been
something else, but I remember it as being big and made of aluminum. It was
also equipped with big round engines. There was one battery in each wing
behind each nacelle. One on the right and one on the left.
The airplane could have been a Lockheed or even a Boeing 247, but I recall
it more as being smaller and, most likely, a Beech Aircraft Corporation
product.
The method of being able to run equipment from one side or the other by
using a double pole double throw switch was pointed out to me as an excellent
idea by the mechanic in charge of that shop where I was a flunky. When I saw
the balanced system used in military aircraft, I was very impressed!
I will be visiting the Beech Museum next month. While I am there, I will
check on construction number eleven model 18 and see how it is set up. The
trouble is, all of the museum aircraft have been modified so often that you
can't really tell if the systems are as they left the factory or not. In most
cases, they are not!
Is there any possibility that Raytheon has documentation that would tell us
how the first 18s were set up?
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
Stearman N3977A
Brookeridge Airpark LL22
Downers Grove, IL 60516
630 985-8502
________________________________________________________________________________
| From: | Speedy11(at)aol.com |
| Subject: | Re: Bottom Line - Seeds of Z-20 are planted! |
Thank you. This sounds like progress.
Stan Sutterfield
www.rv-8a.net
In a message dated 4/5/2005 4:05:59 AM Eastern Standard Time,
aeroelectric-list-digest(at)matronics.com writes:
>All the details of busses and batteries need to be worked out. But this is a
>core part. No crowbar, no OVP, no alternator contactor, no battery
>contactor, no external regulator, no field breaker, no load dump concerns,
>maximum reliability, minimum cost and weight.
Thank you sir! Let me take these words and begin to craft Z-20. I'll
publish the drawing as soon as I can and you can start feeding me errata
and we can begin to discuss the companion notes that will help the
neophyte builder achieve the perceived performance levels.
Bob . . .
________________________________________________________________________________
| From: | "P. Van Caulart" <etivc(at)iaw.on.ca> |
I see there is a conclusion to the OVP issue with Bob and Eric to work
out a Z-20 protocol. I look forward to its development.
I also see that Paul M. has decided to withdraw, not surprised. It's
unfortunate that with his professed engineering ability and many
industry awards and commendations he has not learned empathy or
humility. I have observed the same behavior and outcome from him in
other web groups. His behavior is called "narcissistic entitlement" (see
the web for an explanation).
Compare the last statements of Paul's final post to the identifiable
characteristics of the disorder, to see what I mean.
The "Well Bob you win" quote of Paul's final post really says it all. It
was never about winning, Paul!
PeterVC
________________________________________________________________________________
| From: | "William Yamokoski" <yamokosk(at)lakemichigancollege.edu> |
Great! Now we're making a diagnosis based on email. And I naively
thought you had to actually examine a patient in order to do that.
This virtual world is really something! Boy am I glad I haven't been
following this thread. Wonder what my own personality disorder is
going to turn out to be. I can't wait for the results.
Bill Yamokoski, N4970Y
470 hrs on the Eggensoob, still fighting radio transmission noise
>>> etivc(at)iaw.on.ca 4/5/2005 1:59:00 PM >>>
. I have observed the same behavior and outcome from him in
other web groups. His behavior is called "narcissistic entitlement"
(see
the web for an explanation).
Compare the last statements of Paul's final post to the identifiable
characteristics of the disorder, to see what I mean.
PeterVC
________________________________________________________________________________
| From: | "Jerry Grimmonpre" <jerry(at)mc.net> |
| Subject: | Re: Bottom Line - Seeds of Z-20 are planted! |
Bravo Bob and to others as well ...
----- Original Message -----
From: <Speedy11(at)aol.com>
Subject: AeroElectric-List: Re: Bottom Line - Seeds of Z-20 are planted!
>
> Thank you. This sounds like progress.
> Stan Sutterfield
> www.rv-8a.net
>
>
> In a message dated 4/5/2005 4:05:59 AM Eastern Standard Time,
> aeroelectric-list-digest(at)matronics.com writes:
>>All the details of busses and batteries need to be worked out. But this is
>>a
>>core part. No crowbar, no OVP, no alternator contactor, no battery
>>contactor, no external regulator, no field breaker, no load dump concerns,
>>maximum reliability, minimum cost and weight.
>
> Thank you sir! Let me take these words and begin to craft Z-20. I'll
> publish the drawing as soon as I can and you can start feeding me errata
> and we can begin to discuss the companion notes that will help the
> neophyte builder achieve the perceived performance levels.
>
> Bob . . .
>
>
>
________________________________________________________________________________
| From: | cecilth(at)juno.com |
I think Paul is a person that knows quite a bit about something and
pretends to know the rest and likes to pull someones chain.
He needs to get his own list to prove his concepts. Instead of trying to
pull Bobs character down.
I have had dinner with Bob and he is a very knowledgeable fellow that is
putting his own time in to help others to build a safe plane to fly.
Thanks Bob, remember "sticks and stones Etc."
Cecil
writes:
>
>
> Great! Now we're making a diagnosis based on email. And I
> naively
> thought you had to actually examine a patient in order to do that.
> This virtual world is really something! Boy am I glad I haven't
> been
> following this thread. Wonder what my own personality disorder is
> going to turn out to be. I can't wait for the results.
> Bill Yamokoski, N4970Y
> 470 hrs on the Eggensoob, still fighting radio transmission noise
>
> >>> etivc(at)iaw.on.ca 4/5/2005 1:59:00 PM >>>
>
>
> . I have observed the same behavior and outcome from him in
> other web groups. His behavior is called "narcissistic entitlement"
> (see
> the web for an explanation).
>
> Compare the last statements of Paul's final post to the identifiable
>
> characteristics of the disorder, to see what I mean.
>
>
> PeterVC
>
>
>
>
>
>
>
________________________________________________________________________________
| From: | Charlie Brame <chasb(at)satx.rr.com> |
| Subject: | Re: PMags and RPM |
Maybe I'm missing something in this discussion.
If I understand the E-mag /P-mag setup, both provide electronic ignition
(EI) with an engine driven magneto back up. The EI module in either
provides a hotter spark and a computer derived spark advance like any
other EI system. In the fall back magneto mode, both provide a standard,
25 BTDC, spark.
If the E-mag loses aircraft electrical power (either low voltage or
complete failure) then it reverts to a standard engine driven magneto.
All that is lost is the EI module.
The P-mag has its own alternator which is independent of the aircraft
electrical system. If the P-mag alternator fails to provide sufficient
voltage, due to low RPM or any other reason, it also reverts to an
engine driven magneto. In a low RPM situation, it is probably safe to
say that the EI is already back to a 25 BTDC spark, thus loss of the
P-mag EI due to low RPM is a non-event.
The beauty of the E-mag/P-mag setup, as I understand it, is that one can
have dual EI systems, each backed up by an engine driven magneto, which
negates any need for a backup battery or a standby electrical system
just to power the EI.
Am I wrong?
Charlie
RV-6A N11CB
San Antonio
________________________________________________________________________________
| From: | Harley <harley(at)AgelessWings.com> |
| Subject: | Re: PMags and RPM |
Afternoon, Charlie...
Go here for a very good description of the e-mag and P-mag systems.
>>emagair.com/NextGen.htm<<
They are purely electronic ignition systems, and are not magnetos. They
mount directly in the holes where the magnetos went on the engine, and
use the gear for engine timing, RPM monitoring, etc. They also have a
port that accepts manifold pressure for further monitoring and more
accurate ignition timing if one chooses to use it.
There is nothing mechanical in them to produce a spark as a magneto has.
They rely on the battery/alternator system for power and for spark.
The P-mag has an additional alternator built in to power itself in the
event the aircraft's electrical power system totally fails. As has been
discussed, this alternator inside the P-mag can provide enough energy to
keep the engine running on one unit as long as the RPM is above 800 or
so. If it drops below that, then you have no operating ignition system.
I imagine that under these circumstances, the engine will run as it
normally does on one magneto.
Harley
Charlie Brame wrote:
>
>Maybe I'm missing something in this discussion.
>
>If I understand the E-mag /P-mag setup, both provide electronic ignition
>(EI) with an engine driven magneto back up. The EI module in either
>provides a hotter spark and a computer derived spark advance like any
>other EI system. In the fall back magneto mode, both provide a standard,
>25 BTDC, spark.
>
>If the E-mag loses aircraft electrical power (either low voltage or
>complete failure) then it reverts to a standard engine driven magneto.
>All that is lost is the EI module.
>
>The P-mag has its own alternator which is independent of the aircraft
>electrical system. If the P-mag alternator fails to provide sufficient
>voltage, due to low RPM or any other reason, it also reverts to an
>engine driven magneto. In a low RPM situation, it is probably safe to
>say that the EI is already back to a 25 BTDC spark, thus loss of the
>P-mag EI due to low RPM is a non-event.
>
>The beauty of the E-mag/P-mag setup, as I understand it, is that one can
>have dual EI systems, each backed up by an engine driven magneto, which
>negates any need for a backup battery or a standby electrical system
>just to power the EI.
>
>Am I wrong?
>
>Charlie
>RV-6A N11CB
>San Antonio
>
>
>
>
________________________________________________________________________________
| From: | Harley <harley(at)AgelessWings.com> |
| Subject: | Re: PMags and RPM |
Oh, one more thing, Charlie...you can use one e-mag (or P-mag) with one
normal magneto if you wish. In that case, you have one purely
electronic ignition,, and one old fashioned magneto.
Harley Dixon
Harley wrote:
>
>Afternoon, Charlie...
>
>Go here for a very good description of the e-mag and P-mag systems.
>
> >>emagair.com/NextGen.htm<<
>
>They are purely electronic ignition systems, and are not magnetos. They
>mount directly in the holes where the magnetos went on the engine, and
>use the gear for engine timing, RPM monitoring, etc. They also have a
>port that accepts manifold pressure for further monitoring and more
>accurate ignition timing if one chooses to use it.
>
>There is nothing mechanical in them to produce a spark as a magneto has.
>They rely on the battery/alternator system for power and for spark.
>
>The P-mag has an additional alternator built in to power itself in the
>event the aircraft's electrical power system totally fails. As has been
>discussed, this alternator inside the P-mag can provide enough energy to
>keep the engine running on one unit as long as the RPM is above 800 or
>so. If it drops below that, then you have no operating ignition system.
>I imagine that under these circumstances, the engine will run as it
>normally does on one magneto.
>
>Harley
>
>
>Charlie Brame wrote:
>
>
>
>>
>>Maybe I'm missing something in this discussion.
>>
>>If I understand the E-mag /P-mag setup, both provide electronic ignition
>>(EI) with an engine driven magneto back up. The EI module in either
>>provides a hotter spark and a computer derived spark advance like any
>>other EI system. In the fall back magneto mode, both provide a standard,
>>25 BTDC, spark.
>>
>>If the E-mag loses aircraft electrical power (either low voltage or
>>complete failure) then it reverts to a standard engine driven magneto.
>>All that is lost is the EI module.
>>
>>The P-mag has its own alternator which is independent of the aircraft
>>electrical system. If the P-mag alternator fails to provide sufficient
>>voltage, due to low RPM or any other reason, it also reverts to an
>>engine driven magneto. In a low RPM situation, it is probably safe to
>>say that the EI is already back to a 25 BTDC spark, thus loss of the
>>P-mag EI due to low RPM is a non-event.
>>
>>The beauty of the E-mag/P-mag setup, as I understand it, is that one can
>>have dual EI systems, each backed up by an engine driven magneto, which
>>negates any need for a backup battery or a standby electrical system
>>just to power the EI.
>>
>>Am I wrong?
>>
>>Charlie
>>RV-6A N11CB
>>San Antonio
>>
>>
>>
>>
>>
>>
>
>
>
>
________________________________________________________________________________
| From: | Kevin Horton <khorton01(at)rogers.com> |
| Subject: | Uncovered circuit boards? |
I will be fabricating two small circuits for my RV-8. One will
contain a ULQ-2004A darlington array to control some annunciator
lights, and the other will be some sort of 12V to 28V DC-DC
converter, possibly based on the LM3478 evaluation board from
National Semiconductor.
Both these circuit boards will be mounted somewhere behind the
instrument panel. Should I plan to fabricate some sort of enclosure
for each board, is it is acceptable to mount them uncovered, provided
suitable care is taken to ensure that nothing can short against them?
Enclosed boards look more finished, an enclosure will add weight,
cost and time that I would rather not invest. If the potential for
airborne dust on the boards is a concern, is there any other way to
protect the boards other than by using an enclosure?
Thanks for your advice.
--
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://www.kilohotel.com/rv8
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Uncovered circuit boards? |
>
>I will be fabricating two small circuits for my RV-8. One will
>contain a ULQ-2004A darlington array to control some annunciator
>lights, and the other will be some sort of 12V to 28V DC-DC
>converter, possibly based on the LM3478 evaluation board from
>National Semiconductor.
>
>Both these circuit boards will be mounted somewhere behind the
>instrument panel. Should I plan to fabricate some sort of enclosure
>for each board, is it is acceptable to mount them uncovered, provided
>suitable care is taken to ensure that nothing can short against them?
>Enclosed boards look more finished, an enclosure will add weight,
>cost and time that I would rather not invest. If the potential for
>airborne dust on the boards is a concern, is there any other way to
>protect the boards other than by using an enclosure?
Are these etched boards or hard wired? If etched,
coat them with a clear urethane varnish. 2 or 3 light coats.
Make sure you have a good way to bring wires on and off the
board. D-subs are my favorite.
Our LVWarn/ABMM modules are open boards. See:
http://aeroelectric.com/Catalog/9005Assy.jpg
Bob . . .
________________________________________________________________________________
| From: | Charlie Kuss <chaztuna(at)adelphia.net> |
| Subject: | Re: PMags and RPM |
At 04:45 PM 4/5/2005, you wrote:
>
>Maybe I'm missing something in this discussion.
>
>If I understand the E-mag /P-mag setup, both provide electronic ignition
>(EI) with an engine driven magneto back up. The EI module in either
>provides a hotter spark and a computer derived spark advance like any
>other EI system. In the fall back magneto mode, both provide a standard,
>25 BTDC, spark.
>
>If the E-mag loses aircraft electrical power (either low voltage or
>complete failure) then it reverts to a standard engine driven magneto.
>All that is lost is the EI module.
>
>The P-mag has its own alternator which is independent of the aircraft
>electrical system. If the P-mag alternator fails to provide sufficient
>voltage, due to low RPM or any other reason, it also reverts to an
>engine driven magneto. In a low RPM situation, it is probably safe to
>say that the EI is already back to a 25 BTDC spark, thus loss of the
>P-mag EI due to low RPM is a non-event.
>
>The beauty of the E-mag/P-mag setup, as I understand it, is that one can
>have dual EI systems, each backed up by an engine driven magneto, which
>negates any need for a backup battery or a standby electrical system
>just to power the EI.
>
>Am I wrong?
>
>Charlie
>RV-6A N11CB
>San Antonio
Charlie
The E Mag is an electronic ignition. It is similar to the ElectroAir and
Lightspeed units, except that it is packaged as a single unit. The P Mag
adds a dynamo (they call it an alternator) to provide an internal power
source, independent of the ship's normal power. If this dynamo were to
fail, it can still be run from the ship's main power supply.
Charlie Kuss
________________________________________________________________________________
| From: | Kevin Horton <khorton01(at)rogers.com> |
| Subject: | Re: Uncovered circuit boards? |
>
>
>
>>
>>I will be fabricating two small circuits for my RV-8. One will
>>contain a ULQ-2004A darlington array to control some annunciator
>>lights, and the other will be some sort of 12V to 28V DC-DC
>>converter, possibly based on the LM3478 evaluation board from
>>National Semiconductor.
>>
>>Both these circuit boards will be mounted somewhere behind the
>>instrument panel. Should I plan to fabricate some sort of enclosure
>>for each board, is it is acceptable to mount them uncovered, provided
>>suitable care is taken to ensure that nothing can short against them?
>>Enclosed boards look more finished, an enclosure will add weight,
>>cost and time that I would rather not invest. If the potential for
>>airborne dust on the boards is a concern, is there any other way to
>>protect the boards other than by using an enclosure?
>
> Are these etched boards or hard wired? If etched,
> coat them with a clear urethane varnish. 2 or 3 light coats.
> Make sure you have a good way to bring wires on and off the
> board. D-subs are my favorite.
>
> Our LVWarn/ABMM modules are open boards. See:
>
> http://aeroelectric.com/Catalog/9005Assy.jpg
I'm not sure what you mean by a hard wired board. The ULQ-2004A will
be on a BusBoard-3U-CONN. The board layout is such that I will need
some jumper wires to connect the four lamp power leads to one power
line (although I could do that off-board if that made for a more
reliable system). There will be no wires between the ULQ-2004A and
the DB-25 connector, as the board has copper traces in the
configuration I need to tie them together.
http://www.busboard.net/bps-bb3uc.htm
The DC-DC converter is on a custom evaluation board from National
Semiconductor. It is a work of art, with tiny surface-mount
components. I need to find someone who can change out several of the
resistors and capacitors to adjust the operating voltage.
http://www.national.com/an/AN/AN-1204.pdf
I think both these are etched boards, so I could just coat them with
urethane. The only question is the jumper wires I need. I'll plan
to use insulated jumpers, and coat the exposed portions.
Thanks for the advice. I don't know how you find the time to do all
this in your "spare" time.
--
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://www.kilohotel.com/rv8
________________________________________________________________________________
| From: | luckymacy(at)comcast.net (lucky) |
| Subject: | Re: Uncovered circuit boards? |
I don't know what your Canadian bureaucracy would say but we can in the US.
My *old style* LC-40 light controller is 'exposed'. The new ones have a outer
case. Maybe that's a hint that it might be worth it to make it covered regardless.
Lucky
-------------- Original message --------------
>
> I will be fabricating two small circuits for my RV-8. One will
> contain a ULQ-2004A darlington array to control some annunciator
> lights, and the other will be some sort of 12V to 28V DC-DC
> converter, possibly based on the LM3478 evaluation board from
> National Semiconductor.
>
> Both these circuit boards will be mounted somewhere behind the
> instrument panel. Should I plan to fabricate some sort of enclosure
> for each board, is it is acceptable to mount them uncovered, provided
> suitable care is taken to ensure that nothing can short against them?
> Enclosed boards look more finished, an enclosure will add weight,
> cost and time that I would rather not invest. If the potential for
> airborne dust on the boards is a concern, is there any other way to
> protect the boards other than by using an enclosure?
>
> Thanks for your advice.
> --
> Kevin Horton RV-8 (finishing kit)
> Ottawa, Canada
> http://www.kilohotel.com/rv8
>
>
>
>
>
>
I don't know what your Canadian bureaucracy would say but we can in the US.
My *old style* LC-40 light controller is 'exposed'. The new ones have a outer case.
Maybe that's a hint that it might be worth it to make it covered regardless.
Lucky
-------------- Original message --------------
-- AeroElectric-List message posted by: Kevin Horton
I will be fabricating two small circuits for my RV-8. One will
contain a ULQ-2004A darlington array to control some annunciator
lights, and the other will be some sort of 12V to 28V DC-DC
converter, possibly based on the LM3478 evaluation board from
National Semiconductor.
Both these circuit boards will be mounted somewhere behind the
instrument panel. Should I plan to fabricate some sort of enclosure
for each board, is it is acceptable to mount them uncovered, provided
suitable care is taken to ensure that nothing can short against them?
Enclosed boards look more finished, an enclosure will add weight,
cost and time that I would rather n
ot invest. If the potential for
airborne dust on the boards is a concern, is there any other way to
protect the boards other than by using an enclosure?
Thanks for your advice.
--
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://www.kilohotel.com/rv8
________________________________________________________________________________
| From: | Hopperdhh(at)aol.com |
| Subject: | Emag/mag timing question |
I have some experience in electronic ignition design, and there is a nagging
question in my mind. Apparently I know just enough to be confused!
Assume a system with one electronic ignition system and one magneto.
When the timing is advanced on the plug being controlled by the electronic
ignition, doesn't the cylinder pressure cause electrical stress on the magneto
system -- the coil, cap and plug wiring? Isn't the KV requirement of the
magneto significantly increased by the increased pressure in the chamber after
the fuel has been ignited by the earlier firing electronic ignition?
If some ignition gurus could address this question, I would really
appreciate it.
Thanks,
Dan Hopper
hopperdhh at aol.com
Walton, IN
RV-7A (Flying since last July. Now being painted.)
________________________________________________________________________________
| From: | Hopperdhh(at)aol.com |
| Subject: | emag/mag timing question |
I have some experience in electronic ignition design, and there is a nagging
question in my mind. Apparently I know just enough to be confused!
Assume a system with one electronic ignition system and one magneto.
When the timing is advanced on the plug being controlled by the electronic
ignition, doesn't the cylinder pressure cause electrical stress on the magneto
system -- the coil, cap and plug wiring? Isn't the KV requirement of the
magneto significantly increased by the increased pressure in the chamber after
the fuel has been ignited by the earlier firing electronic ignition?
If some ignition gurus could address this question, I would really
appreciate it.
Thanks,
Dan Hopper
hopperdhh at aol.com
Walton, IN
RV-7A (Flying since last July. Now being painted.)
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Emag/mag timing question |
>
>
>I have some experience in electronic ignition design, and there is a nagging
>question in my mind. Apparently I know just enough to be confused!
>
>Assume a system with one electronic ignition system and one magneto.
>
>When the timing is advanced on the plug being controlled by the electronic
>ignition, doesn't the cylinder pressure cause electrical stress on the
>magneto
>system -- the coil, cap and plug wiring? Isn't the KV requirement of the
>magneto significantly increased by the increased pressure in the chamber
>after
>the fuel has been ignited by the earlier firing electronic ignition?
If it does, the effects must be insignificant. Yes, when at low manifold
pressures, the electronic ignition will advance and pressure in the
cylinder
will no doubt be on the rise when the johnny-come-lately mageneto fires.
The pressures may indeed be so great the a spark never materializes across
the plug's electrodes.
The OBAM community has been flying one-mag/one-electronic now for over 15
years. I have to believe that if the phenomenon you've identified was
a significant problem that we would have heard about it by now. Why
not two electronic ignitions? The cost savings in spark plugs alone
is pretty attractive.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Uncovered circuit boards? |
>
>
>I think both these are etched boards, so I could just coat them with
>urethane. The only question is the jumper wires I need. I'll plan
>to use insulated jumpers, and coat the exposed portions.
I think what you've proposed will live happily behind the panel
un-housed if you give it some decent moisture/dust protection.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Two independent systems |
>
>
>In a message dated 4/5/2005 12:07:30 P.M. Central Standard Time,
>b.nuckolls(at)cox.net writes:
>
>Interesting! Can you recall a model? My hands on experience with
>the Wichita crop of spam cans is limited and dates back to my
>days of working production jobs in the 60's. I don't think anything
>we did here offered total redundancy . . . in fact, our BIG emphasis
>was accurately paralleling two generators (and later alternators)
>to share the loads while driving a single battery and bus. I'd
>be interested in knowing the history of any alternatives to that
>philosophy in certified ships.
>
>Bob . . .
>
>
>Good Afternoon Bob,
>
>It was back when I was a line boy (1945/46) and occasional shop flunky.
>Later on, I went into the USMC and was trained as an
>Aviation Electricians Mate
>(That meant I got to change batteries and light bulbs. Anything more serious
>was sent to A&R (Assembly and Repair))
>
>While in AME school, I was introduced to the intricacies of balancing the
>generators via the carbon pile voltage regulators. That brought
>back memories
>of the airplane I had seen that had the isolated systems with transfer
>switches for certain components.
>
>In the far recesses of my mind, I think the airplane was one that preceded
>the ones you are now working on, the very early Beech 18. It could
>have been
>something else, but I remember it as being big and made of aluminum. It was
>also equipped with big round engines. There was one battery in each wing
>behind each nacelle. One on the right and one on the left.
>
>The airplane could have been a Lockheed or even a Boeing 247, but I recall
>it more as being smaller and, most likely, a Beech Aircraft Corporation
>product.
>
>The method of being able to run equipment from one side or the other by
>using a double pole double throw switch was pointed out to me as an
>excellent
>idea by the mechanic in charge of that shop where I was a flunky. When
>I saw
>the balanced system used in military aircraft, I was very impressed!
>
>I will be visiting the Beech Museum next month. While I am there, I will
>check on construction number eleven model 18 and see how it is set up. The
>trouble is, all of the museum aircraft have been modified so often that you
>can't really tell if the systems are as they left the factory or not. In
>most
>cases, they are not!
>
>Is there any possibility that Raytheon has documentation that would tell us
>how the first 18s were set up?
>
>Happy Skies,
>
>Old Bob
>AKA
>Bob Siegfried
>Ancient Aviator
>Stearman N3977A
>Brookeridge Airpark LL22
>Downers Grove, IL 60516
>630 985-8502
>
>
>--
>
>
>-- incoming mail is certified Virus Free.
Bob . . .
--------------------------------------------------------
< Throughout history, poverty is the normal condition >
< of man. Advances which permit this norm to be >
< exceeded -- here and there, now and then -- are the >
< work of an extremely small minority, frequently >
< despised, often condemned, and almost always opposed >
< by all right-thinking people. Whenever this tiny >
< minority is kept from creating, or (as sometimes >
< happens) is driven out of a society, the people >
< then slip back into abject poverty. >
< >
< This is known as "bad luck". >
< -Lazarus Long- >
<------------------------------------------------------>
http://www.aeroelectric.com
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: Two independent systems |
>
>
>Good Afternoon Bob,
>
>It was back when I was a line boy (1945/46) and occasional shop flunky.
>Later on, I went into the USMC and was trained as an
>Aviation Electricians Mate
>(That meant I got to change batteries and light bulbs. Anything more serious
>was sent to A&R (Assembly and Repair))
>
>While in AME school, I was introduced to the intricacies of balancing the
>generators via the carbon pile voltage regulators. That brought
>back memories
>of the airplane I had seen that had the isolated systems with transfer
>switches for certain components.
>
>In the far recesses of my mind, I think the airplane was one that preceded
>the ones you are now working on, the very early Beech 18. It could
>have been
>something else, but I remember it as being big and made of aluminum. It was
>also equipped with big round engines. There was one battery in each wing
>behind each nacelle. One on the right and one on the left.
>
>The airplane could have been a Lockheed or even a Boeing 247, but I recall
>it more as being smaller and, most likely, a Beech Aircraft Corporation
>product.
>
>The method of being able to run equipment from one side or the other by
>using a double pole double throw switch was pointed out to me as an
>excellent
>idea by the mechanic in charge of that shop where I was a flunky. When
>I saw
>the balanced system used in military aircraft, I was very impressed!
>
>I will be visiting the Beech Museum next month. While I am there, I will
>check on construction number eleven model 18 and see how it is set up. The
>trouble is, all of the museum aircraft have been modified so often that you
>can't really tell if the systems are as they left the factory or not. In
>most
>cases, they are not!
>
>Is there any possibility that Raytheon has documentation that would tell us
>how the first 18s were set up?
I've asked for weirder stuff and got answers. I'll ask tomorrow.
I'd really like to see the wiring diagrams for the first Bonanzas
too.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
>
>
>Bob, at what point do you stop repeating yourself and realize your request
>for clarification is not being addressed? At what point to you stop doing
>work to disprove or quantify accusers unsupported and vague claims? When
>should they be responsible for SUPPORTING data behind a critique, OR EVEN
>CLEARLY ARTICULATING said critique?
I'm the eternal optimist. I really had hopes of engaging Paul
in some useful dialog that would ultimately result in the publication
of lucid documents to describe his vision. I've lived in
the wild and wooly world of DO160/M704 for decades and I'm quite
comfortable with it. It would be really nice if the new kids on the
block had a gentler and friendlier electrical environment to live in.
I don't know that it cannot be achieved . . . but we need to
be careful lest a quest to relieve a perceived obstacle somewhere
doesn't have unforeseen and unhappy fallout later.
I had two rounds of e-mail exchanges with Greg after I stopped appending
them to the review of "Aircraft Wiring for Smart People" . . . again,
I never received an answer to a single question. I happily gave up on that
one but I'm not happy about Paul. His vision is attractive and if it
can be supported in physics and practical processes, it would be a
grand addition to OBAM aircraft's collective bag of tricks.
Bob . . .
________________________________________________________________________________
| From: | "Wayne Sweet" <w_sweet(at)comcast.net> |
| Subject: | Re: Emag/mag timing question |
----- Original Message -----
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: AeroElectric-List: Emag/mag timing question
>
>
>
>>
>>
>>I have some experience in electronic ignition design, and there is a
>>nagging
>>question in my mind. Apparently I know just enough to be confused!
>>
>>Assume a system with one electronic ignition system and one magneto.
>>
>>When the timing is advanced on the plug being controlled by the electronic
>>ignition, doesn't the cylinder pressure cause electrical stress on the
>>magneto
>>system -- the coil, cap and plug wiring? Isn't the KV requirement of the
>>magneto significantly increased by the increased pressure in the chamber
>>after
>>the fuel has been ignited by the earlier firing electronic ignition?
>
> If it does, the effects must be insignificant. Yes, when at low
> manifold
> pressures, the electronic ignition will advance and pressure in the
> cylinder
> will no doubt be on the rise when the johnny-come-lately mageneto
> fires.
> The pressures may indeed be so great the a spark never materializes
> across
> the plug's electrodes.
>
> The OBAM community has been flying one-mag/one-electronic now for over
> 15
> years. I have to believe that if the phenomenon you've identified was
> a significant problem that we would have heard about it by now. Why
> not two electronic ignitions? The cost savings in spark plugs alone
I agree and did exactly that, since the mag was along for the ride anyway,
not contributing anything unless
the CDI was turned off.
> is pretty attractive.
>
> Bob . . .
>
>
>
________________________________________________________________________________
| Subject: | Emag/mag timing question |
| From: | "George Braly" <gwbraly(at)gami.com> |
Why
not two electronic ignitions? The cost savings in spark plugs alone
is pretty attractive.
Bob . . .
Bob, Why do you think that you get better spark plug life from an electronic system
than you do from a magneto fired spark ?
Regards, George
---
________________________________________________________________________________
| From: | "Hinde, Frank George (Corvallis)" <frank.hinde(at)hp.com> |
Hello there,
I was listening to an urban legend that told me the best hi output
alternator for use on a Lycoming clone was from a 1987 Toyota Camry. I
went to Autozone and bought said alternator and found it has a
serpentine belt pulley on it.
Clearly this is not correct so now I am wondering if the Camry unit
really is the right one and where one can buy a v groove pulley to match
the Lyc...I don't have the engine yet either so I'm sure even if I do go
get a v pulley if it will be the correct profile...Like are all V
pulleys the same?
I have a 1987 Suzuki Samuri unit on my existing plane but this unit will
not have enough output for my IFR equipped RV.
Any help greatly appreciated.
Frank
________________________________________________________________________________
| From: | Dj Merrill <deej(at)thayer.dartmouth.edu> |
| Subject: | Re: Emag/mag timing question |
George Braly wrote:
> Bob, Why do you think that you get better spark plug life from an electronic
system than you do from a magneto fired spark ?
>
> Regards, George
Hi George,
The electronic systems generally use automotive spark
plugs, which are significantly cheaper (an order of magnitude)
than the aircraft spark plugs. You'd have to go through
10 auto spark plugs to equal the cost of a single
aircraft spark plug, so the savings is significant
even if you replaced them 4-5 times more often than
an aircraft spark plug (which I don't think is the case).
At least, I think that is what he is referring to... :-)
-Dj
--
Dj Merrill
deej(at)thayer.dartmouth.edu
"TSA: Totally Screwing Aviation"
________________________________________________________________________________
| From: | "DonVS" <dsvs(at)comcast.net> |
| Subject: | Emag/mag timing question |
George,
I think that plug life was not the reason for the cost savings. The use of
automotive plugs is the big cost savings. Don (P-mags on ac plugs)So I
guess I do not save any money(G)
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com]On Behalf Of George
Braly
Subject: RE: AeroElectric-List: Emag/mag timing question
Why
not two electronic ignitions? The cost savings in spark plugs alone
is pretty attractive.
Bob . . .
Bob, Why do you think that you get better spark plug life from an
electronic system than you do from a magneto fired spark ?
Regards, George
---
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> |
| Subject: | Re: OVP, grounds, resistive loads |
>
>
>Bob...
>
>Thanks for a great 'lectric seminar in Independence, OR! You are more
>then patient with answering my many questions. As with any educational
>endevour it has made me question some assumptions and added to a better
>understanding of others. Again... Thank you!
Thank you sir. I'm always gratified with people's appreciation for
the seminars but it's I who is indebted to you. It's my JOB to produce
those programs. You could have walked out of that seminar and told me
that it wasn't worth what I was asking, and I wouldn't have charged
you for it. You would have wasted a couple of days but my years of
preparation would have been found wanting. Your perception of my product
as being worthy of your $time$ says we have a good supplier/customer
relationship which ratifies what I've produced thus far. Further, it
encourages me to look for ways to increase the value of what I offer.
>As I get deeper into the wiring of the first of two RV 8s the discussions
>of OVP here seem to raise more questions then answers.
>
>1. I am using the Fig. Z-13/8 as a template with the addition of an
>avionics master in between the main bus and endurance bus. A Nippondenso
>40 Amp alt. with internal regulator and a three terminal alternator
>disconnect contactor. A B&C OVM-14. The OVM-14 sense lead is connected
>directly to the master sw (faston crimped onto the uncut yellow
>lead). The black lead is butt spliced to a six foot AWG 20 ground that
>connects to the forest of fastons bolted to the firewall and connected to
>the bat neg. by 8 ft of AWG 2 welding cable. After reading your white
>paper on OVP wire resistance appears to be a variable that may add to the
>current spike across the 5A breaker. Is this acceptable?
Actually, the additional wire significantly REDUCES the crowbar
event current. In fact, most builders have installed it as the
Z-figures suggest and the longer ground wire exists in most of
the airplanes using the OVM-14 as you've described.
I believe my inquiries to Eaton/Cutler-Hammer will confirm my
suspicions that opening the CB with more that 1000% of rated
current is a service life issue and not a catastrophic failure
issue. However, having said that, I have to note that decreasing
CB opening current makes it take longer to open. Adding this time
on top of opening time of the b-lead contactor puts the contactor
itself at-risk for a post-trip fire between the contactor's major
conductors.
So, if anyone DOES have a true ov condition that has been brought
under control by an OVM-14/b-lead contactor, I'd REALLY like to get
the contactor back to look at. As soon as I can get my own alternator
stand running, I'll look into this supposition in more detail. In
the mean time, I don't perceive any reason to rip out what you have
in favor of replacing it with something "more suitable." This is
mostly because I'm not sure what is really more suitable.
If we could identify a particular internally regulated alternator that's
as "reliable as prop bolts", then the ideas proffered by Eric and
Paul are pretty attractive.
My critical design review response is, "If such an combination
exists, let's identify it with sufficient accuracy that the
neophyte builder can be reasonably expected to acquire the right
device." Folks have suggested that a "high quality" rebuild
is what we're looking for . . . don't know what that is. If
I walk into any parts store and ask for a "high quality" alternator,
I'm sure they'll assure me that whatever they have to offer will
meet my needs.
>2. I am using a single point ground for all grounds per above
>description. Z-13 shows a firewall ground, instrument ground and avionics
>ground. I don't see any reason not to combine all these to a single
>point. Am I missing something?
No . . . but there may be considerable convenience realized
from an "avionics ground" on the panel. Wait until chapter 18
comes out in R11 and let's revisit this topic.
>3. Pure resistive loads (heater elements)should not be a source of
>electrical noise. That said, I am locally grounding the pitot heat and
>seat heaters. Again, am I missing anything here?
Nope, you can ground such devices locally to airframe . . . also
nav lights, pitot heat, landing lights, and even the strobe power
supply.
>4. The wire feeding the main bus is shown unprotected. In my ship this
>is four feet of AWG 6 that goes from the bat side of the starter contactor
>to the main fuse block. I realize that turning off the master turns
>this off, but a short to ground along this wire run could be
>disastrous! Do I need to be concerned?
No, even the FARS exempt these fat feeders from special
protection . . . just take some care to insure their mechanical
integrity and freedom from physical compromise.
>Per the ongoing discussions here by Paul, Eric et al one valid issue
>raised is system reliability by virtue of simplicity. The simplicity of
>an internally regulated alternator vs an externally regulated alternator
>with the additional wiring and connections required to connect the
>external voltage regulator would seem to favor the internally regulated
>"one piece" charging system.
Absolutely! All other things being equal, lower parts count
produces lower failure rates. The talented designer's goals
are to deduce equivalency, illuminate failure mode effects,
and discover the ultimate reliability of any and all parts
used. My approach for the neophyte builder has been to ASSUME
all parts are capable of failure . . . and crafting a minimum
parts count system to address this. Since I'm not privy to
internal workings of all regulator products, I cannot say of
my own knowledge that they are either 10 to the minus whatever
reliable nor can I deduce failure modes. Therefore my designs
err on the side of worst case assumptions.
>At this point I am going to use the crowbar OVP due to it's simplicity
>albeit the brute force approach.
I'm going to continue to look into the issues that Paul raised
and will publish my findings here along with any recommendations
for replacing (or more tightly controlling) the installations
so as to reduce risk.
I'm just not ready to jump on a band-wagon to advocate
any changes at present because I simply don't have all the
questions answered yet.
Bob . . .
________________________________________________________________________________
March 31, 2005 - April 05, 2005
AeroElectric-Archive.digest.vol-ef