Today's Message Index:
----------------------
1. 01:40 PM - Strobe power pack ground (Jerry Ricciotti)
2. 03:29 PM - Re: Strobe power pack ground (Robert L. Nuckolls, III)
3. 05:57 PM - Re: Nippondenso alternator question (Robert L. Nuckolls, III)
4. 06:25 PM - Alternator Questions (OOPS) Forgot to link the schematic!! (Robert L. Nuckolls, III)
5. 09:24 PM - Rare find . . . (Robert L. Nuckolls, III)
6. 11:02 PM - Re: Nippondenso alternator question (Paul)
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Subject: | Strobe power pack ground |
Greetings
Reference the shielded wire on strobes, the Whelan installation
instructions ground the shielding at the power pack only. Should I
ground the shielding to airframe at the power pack or back to forest of
tabs on the firewall via same ground wire as the power cable
connection. ( Or does it matter?)
Regards Jerry
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Subject: | Re: Strobe power pack ground |
At 04:35 PM 7/12/2008 -0400, you wrote:
>Greetings
>
>Reference the shielded wire on strobes, the Whelan installation
>instructions ground the shielding at the power pack only. Should I ground
>the shielding to airframe at the power pack or back to forest of tabs on
>the firewall via same ground wire as the power cable connection. ( Or
>does it matter?)
Locally to the same bolts that hold the power
pack to its mounting surface.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
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Subject: | Re: Nippondenso alternator question |
At 10:28 AM 7/10/2008 -0700, you wrote:
>
>>THANK YOU for your very nice reply!!
>>
<snip>
>>In any event its now my turn to start one subject at a time in replying
>>to your comments and questions.
Paul, how about we avoid turning this into an unnecessary and/or
unproductive research/science project . . . It would be useful to
craft a sort of mission statement where goals, impediments to
goals, questions and plans for acquiring data that go to aswering
those questions are identified up front. To that effort I'll offer
the following:
1) Since day-one, electrical systems in aircraft have offered
a means by which engine driven power sources may be turned on
and off at will of the pilot. This absolute ON/OFF control goes
to a number of issues that include but are not limited to
preflight testing, load management, ability to take a mis-behaving
system off line, and plan-B activities crafted to mitigate
effects of failure. I.e., failure tolerance.
2) The modern automotive alternator has a proven track record
in ground based vehicles that eclipses anything flying
by an order of 1000:1 or more. It's inarguable that sources
of automotive components from salvage yards up through the
chain to manufacturers of modern components offer the OBAM
aircraft community a treasure-trove of choices.
3) The shear magnitude of choices can be a boon in terms
of potential return on investment for performance and
reliability . . . and a bane in terms of the complexity
for choosing "suitable" hardware from an overwhelming
universe of products and sources.
4) As knowledgeable and experienced practitioners of the
art and sciences we can relieve OBAM aircraft owner/operator
concern for making choices while minimizing risk for having made
a "bad" choice? I'll have to qualify "bad" . . . EVERY
piece of hardware we choose to bolt to an airplane will fail
at some point in time irrespective of its source or perceived
quality. Failure can be due to quality issues . . . operation
outside design limits . . . or the thing simply wears out.
5) My personal preference for minimizing risk is to craft
failure tolerant architectures . . . if we do
that job well, then it doesn't matter if the platinum
plated part fails because some kid didn't tighten a
bolt (quality issue). . . or failed because the part is
one step above junk (design or manufacturing issue).
Failure tolerance is the most powerful tool for risk
management we can bring to the table.
6) You appear to be crafting a risk mitigation
approach along with relief of the decision making process
in the form of specific architectures crafted from
specific part numbers. You believe this approach
is attractive to potential customers. This is the
essence of entrepreneurial opportunity in what is
still (unlike TC aviation) a relatively free marketplace.
Your approach borrows from the legacies of TC aviation
by specifying a design and more controlled suite of
components. No doubt here are/will-be customers
attracted to this approach and I'm sure we all wish
you well in your endeavor. My entrepreneurial leanings
go to system integration hardware, products that help
the OBAM aircraft builder comfortably integrate a host
of choices into the airplane. But first, I need to achieve
an understanding of the simple-ideas that go into
our respective inventions . . . ingredients that drive
recipes for success.
7) We have a common need to exercise a solid grasp
of the same simple-ideas even if our respective inventions
have no competitive features. The most pressing question
for me is understanding the load-dump characteristics
of our favorite alternators under conditions likely to
be encountered in a typical installation on a Lycoming -
spinning like a whirling dervish and subject to
unloading under any condition between zero and full
output with normal regulation. This means knowing the magnitude,
source impedance and timing of the transient that occurs
after sudden load removal at all corners of the
operating envelope.
8) The very first experiment I plan to conduct after
the alternator drive stand is running is based on
the sketch at:
On a 60A machine with battery disconnected,
I'd get data plots of load dumps at 4, 6, 8, 10
and 12KRPM for fixed load of 50A with a 10A dump,
fixed load of 40A with 10A and 20A dumps, fixed
of 30A and 10, 20 30A dumps . . . I think you'll see
the pattern here.
The goal would be to calculate/measure the peak
voltage, total energy and duration of each overshoot
event (or series of overshoots assuming the regulator
control loop is poorly damped). I would probably
set up to run external regulators (of the type
normally installed inside) so that I could explore
the differences between various regulators while
holding the alternator constant.
Obviously a big task to gather enough data to
be reasonably sure we understand the majority of
the fleet . . . assuming we discover wide variances.
(9) The next tests would involve system behavior under
runaway conditions. Artificially fail a regulator
and plot dv/dt at the bus and di/dt at the battery
with various fixed loads . . . one suite of plots
with a fresh battery, another with a battery that
has fallen to 1/2 capacity or less.
Having this data on only one combination of
alternator/regulator would set the order of magnitude
for energies involved. Once the equipment for the
testing is in place and the procedure tuned, it would
probably take less than a half hour to test any other
combination.
I ran all these tests that supported products I designed
for Beech and others many moons ago. But the only
data acquisition we had then were storage 'scopes and
chart recorders. You could "eyeball" the data for gross
suitability to task but real energy studies were exceedingly
difficult . . . they were never done. We can do a much
better job today.
The task is to characterize the dynamic response to
load change for a normally functioning as well as
a runaway alternator. The data collected would allow
a designer to craft systems that deal quietly and
capably with the voltages, currents and energies that
are present during recovery from both a load-dump
and hard-failure conditions.
This was the kind of data I was hoping to gather
some years back when there was discussion about
you and Eric teaming on some sort of activity. I
wasn't sure exactly what equipment you were going to
have access to . . . or what testing satisfied
curiosities for your project . . . but I had hopes
of piggy-backing studies above if you didn't already
have similar data.
Do I presume that for your needs, no further
investigation is necessary/useful to your task?
Know that all of my own test results will be published
on aeroelectric.com and that my equipment will be available
to you (or anyone else in the OBAM aviation community)
should new questions arise.
I'm going to have Zach start stripping out the automotive
test setup wiring from the test stand next week. We'll
leave only the 3-phase motor drive wiring intact. We'll
Z-12 and Z-13/8 architectures in the stand. I already
have a small drive stand for second alternators up to 20A.
I have a static phase converter to install in the
big stand. We'll see we can get the motor and variable
speed drives to run. That will be a BIG step. Not sure
if we'll be able to do real testing before we have to
pack up and move to M.L. I have a contractor running
a fat 240 feeder to the shop at the same time we excavate
for a new retaining wall at the back of the yard. So the
heavy/dirty/ugly work should be behind us at both
locations this summer.
Bob . . .
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Subject: | Alternator Questions (OOPS) Forgot to link the schematic!! |
8) The very first experiment I plan to conduct after
the alternator drive stand is running is based on
the sketch at:
http://aeroelectric.com/Pictures/Schematics/Alternator_Test_Setup.pdf
Bob . . .
Message 5
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Stumbled across this document published by Delco-Remy in 1959.
It's a service manual that speaks to 6v generators and their
companion electro-mechanical regulators. It's doubtful that
many of you will ever encounter this technology in operation
but I found the document interesting and thought I would
share it with you.
http://aeroelectric.com/Mfgr_Data/Regulators/Delco-Remy/Delco-Remy_Generator_Regulators.pdf
I have a lot of respect for the designers that had to accomplish
these tasks with copper, steel, bakelite and a few tungsten
contact points.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
Message 6
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Subject: | Re: Nippondenso alternator question |
Well (very sadly but it did seem too good to be true and I am not surprised)
I had hoped for mutual cooperation but I guess you want to do it all your
self. Good timing as I was just finishing the first part of the planned
discussion.
Be my guest, I had thought you had changed. Clearly you want yo frive the
discussion VS get the benefit of my extensive work.
Random comments as its not worth my time to put them in ordered sequence. I
have made some suggestions about how and what to test to avoid missing
information that is not gathered just using your sketched circuit.
You are incorrect about my approach and intent and about my past analysis
and testing which is in my opinion adequate to determine the problem and I
have "crafted" a proven solution. In my opinion there is ZERO need for more
testing other for self aggrandizement. I find this sad as you have not seen
any real results of my testing nor the scope of it. Reading your suggested
approach I find little to agree with so there is no point in my being a part
of your long promised study.
Further most of your below comments about my position are totally incorrect
assumptions which is not surprising as you have never spent the time to find
out what my approach is; the amount of analysis, investigation nor testing
setup and results. I will not tolerate testing as anything other as proof of
pre testing design analysis. I also simply will not design using assumptions
or unofficial verbal assurances from one manufacturer its safe to exceed the
specifications as that is simply a high risk approach no engineer will do.
My results are identical design solution for all reasonable alternator but
clearly its not reasonable to allow any alternator to be covered and that
position indicates to me a lack of modern alternator designs etc. Further
you seem fixated on maintaining several design flexibilities and pilot
control that I feel is not only not required but potentially dangerous.
Also your sketch does not reproduce the real world load dump conditions what
with fixed load and relay contact bounce in the real circuit. Finally it
appears you intend to have a constant string of load dumps which is very
likely to destroy the internal to the regulator load dump protection
components. Each single load dump needs time for the protection circuits to
cool down.
Hopefully you will end up with far more evaluation, studying, and testing
than what you listed below as its not adequate nor has it addressed ALL the
problems I have addressed. You really should test all the brands of
alternators you intend to approve of and in the several different types and
amps in each style. There are differences to consider. For example different
regulator transient response as well as the winding charactericts which will
determine the load dump information.
Further you should take note of the fact just how much (or more important,
how little) is replaced in rebuilt alternators as if you know what is
replaced you would never recommend a rebuilt alternator (rebuilt is a
misnomer minimal repair is what actually happens).Junk yard is not a source
for ANY aircraft as who knows how close to failure the parts are. In any
event testing alone, with out first doing an analysis and manufacturers
detailed data is NEVER sufficient. Both Myself and Jet Pilot found getting
more detailed information was not easy and getting past the sales staff if
difficult at best. However a lot of useful information was passed on and
po-poed on this groups list.
Also be sure to test with a full load current and zero fixed load. Note my
selected 50 amp rated alternator is specified to put out 70 amps at 13V and
more amps at lower voltages so a full output failure results in a much
higher current than your suggested testing which based on my testing is not
nearly worst case! Another comment about getting the real data first. My NEW
alternator came with a computer printout of the actual alternator during
final test prior to shipment. Note the full amp output is a lot higher than
past comments have been clearly assumed on this list in the past. 40% higher
is not small in my opinion and under load dump conditions the load being
dumped is much higher energy as well as the peak voltage. My testing was
based on a real duplication of a typical aircraft wiring including wire
gauge and lengths as well as flight batteries. It started with your OVP and
contactor with the diode on the contactor coil. Very different than what
your sketch shows. Also very long alternator failure point to final
contactor opening requiring voltage clamping during that time of a lot more
energy than what has been assumed in one of your tests from years ago.
But then we have a large and fundamental difference on how to design any
electrical (including aircraft) systems. My approach is to discard many of
the proven pilot opportunities to mess up that have been a reason for past
crashes and leap into the 21st century. Building on the past and not address
the fundamental cause of most accidents is not progress in my opinion. The
more pilot required actions greatly increases the pilots lack or incorrect
action. Today there is no need to do things manually in most cases. Every
manual control available to the pilot 's another opportunity to make a
mistake that can lead to a crash. Today we have Integrated Solid state
switches/circuit breakers. Schottly diodes are not really needed much less
silicon bridges which have no use in aircraft. Yes Solid state switching is
easy to make with full bi-directional isolation and ON resistance less that
of mechanical relays etc switching (as low as 0.002 ohms ON resistance). The
pilot needs to be notified of any CB failure not by finding out by failure
of the component to work for example.
The aircraft instruments have migrated from steam gauges to flat panels yet
we still find the old contactor relay// switch approach of 1950 etc and that
ignores the modern components available today that are far more reliable and
more pilot friendly.
Its a fact that pilot error is the major cause of accidents. Its pilot error
if you run out of fuel, deplete the battery based on an assumption of
battery condition and electrical load etc etc. The requirement to throw a
switch in an emergency is bad design if there is a reasonable solution that
eliminates the mechanical pilot action and its done automatically. Its sad
that there is no truly modern system available at a reasonable price on the
market today that automates the system and provides the pilot with useful
real time electrical system conditions. My designs have been peer reviewed
by my (multiple) peers and all have stated its both more reliable and a
great improvement to current 1950's parts and today's arrangements and
approaches. You have long promoted fly the airplane and trouble shoot back
on the ground which is not what your design requirement to turn on and off
the alternator in flight and a simple voltage check is enough for preflight.
Personal situation has delayed getting my system on the market.
The E bus is a good example where there is a design requirement to have a
group of avionics disabled during part of the flight and then guess about
how much battery life is left. A simple additional electrical instrument I
have designed allows the pilot to simply see the real flight time left and
change the load and have the flight time left update. It also determines the
true battery life dynamically. If I am IFR I may need a different set of
avionics than what is on the E bus for example depending on the actual
flight conditions. Or what if the battery power left at any point is less
that what was predicted or measured months ago?. I know of several off
field crashes due to the battery being depleted well before the expected
time. Another bad design to assume something in particular when it ns not
required to assume. Fuel tank gauges system when the only accurate
requirement is full and empty has been replaced with fuel flow measurement
and totalized as seen in modern automobiles. No reason the battery cannot be
treated the same way, sure its a little more complex but not hard to do with
reasonable accuracy.
There are many ways to make flying safer than having a check list of which
switches to throw under different failure modes and make assumptions of
flight time left for example. How about a warning and a count down display
that tells the time left to fly and updates as the pilot changes the
equipment powered on. No action is required if the time remaining is long
enough.
Your insistence of performing your own testing is fine but you are
discarding months of investigation as well as hundreds of hours of testing
and analysis. On the other hand it will save me a lot of time producing a
machine readable copy etc.
A lot of people blindly used your OVP crowbar until it was used with Vans
aircraft and had many reported failures. As far as I know there was never
and failure analysis to prove the true reason for the failures. My own
testing found fault at least two faults with the OVP design but they only
caused false tripping and the real reason appeared to be the use of the
contactor and perhaps rebuilt alternators with possible second rate (read
lower cost) regulators that could not stand up to the resulting load dump
voltage peaks. In any event the OVP design was not properly desinged in the
first place likely due to the test first and skip the analysis under
transient conditions.
It is true I had intended to produce an engineering document VS a
technicians experimental results
I have far too much to do, so its easy to simply bow out. Further I will not
comment on your results as I have better things to do. There is no need to
try to discuss your approach as your mind is seemingly always made up ahead
of time.
You win and I think the group looses. Jet Pilot tried with a lot of real
research and was not listened to either.
We have very very different backgrounds and approaches to design. I had
hoped we could work together but that is not to be. I simply do not have the
time, nor can I stand the frustration of writing one paragraph and getting a
response of several pages of comments which are mostly, to me, not to the
point.
Best wishes
Paul
----- Original Message -----
From: "Robert L. Nuckolls, III" <nuckolls.bob@cox.net>
Sent: Saturday, July 12, 2008 5:53 PM
Subject: Re: AeroElectric-List: Nippondenso alternator question
> <nuckolls.bob@cox.net>
>
> At 10:28 AM 7/10/2008 -0700, you wrote:
>>
>>>THANK YOU for your very nice reply!!
>>>
>
> <snip>
>
>>>In any event its now my turn to start one subject at a time in replying
>>>to your comments and questions.
>
> Paul, how about we avoid turning this into an unnecessary and/or
> unproductive research/science project . . . It would be useful to
> craft a sort of mission statement where goals, impediments to
> goals, questions and plans for acquiring data that go to aswering
> those questions are identified up front. To that effort I'll offer
> the following:
>
> 1) Since day-one, electrical systems in aircraft have offered
> a means by which engine driven power sources may be turned on
> and off at will of the pilot. This absolute ON/OFF control goes
> to a number of issues that include but are not limited to
> preflight testing, load management, ability to take a mis-behaving
> system off line, and plan-B activities crafted to mitigate
> effects of failure. I.e., failure tolerance.
>
> 2) The modern automotive alternator has a proven track record
> in ground based vehicles that eclipses anything flying
> by an order of 1000:1 or more. It's inarguable that sources
> of automotive components from salvage yards up through the
> chain to manufacturers of modern components offer the OBAM
> aircraft community a treasure-trove of choices.
>
> 3) The shear magnitude of choices can be a boon in terms
> of potential return on investment for performance and
> reliability . . . and a bane in terms of the complexity
> for choosing "suitable" hardware from an overwhelming
> universe of products and sources.
>
> 4) As knowledgeable and experienced practitioners of the
> art and sciences we can relieve OBAM aircraft owner/operator
> concern for making choices while minimizing risk for having made
> a "bad" choice? I'll have to qualify "bad" . . . EVERY
> piece of hardware we choose to bolt to an airplane will fail
> at some point in time irrespective of its source or perceived
> quality. Failure can be due to quality issues . . . operation
> outside design limits . . . or the thing simply wears out.
>
> 5) My personal preference for minimizing risk is to craft
> failure tolerant architectures . . . if we do
> that job well, then it doesn't matter if the platinum
> plated part fails because some kid didn't tighten a
> bolt (quality issue). . . or failed because the part is
> one step above junk (design or manufacturing issue).
> Failure tolerance is the most powerful tool for risk
> management we can bring to the table.
>
> 6) You appear to be crafting a risk mitigation
> approach along with relief of the decision making process
> in the form of specific architectures crafted from
> specific part numbers. You believe this approach
> is attractive to potential customers. This is the
> essence of entrepreneurial opportunity in what is
> still (unlike TC aviation) a relatively free marketplace.
> Your approach borrows from the legacies of TC aviation
> by specifying a design and more controlled suite of
> components. No doubt here are/will-be customers
> attracted to this approach and I'm sure we all wish
> you well in your endeavor. My entrepreneurial leanings
> go to system integration hardware, products that help
> the OBAM aircraft builder comfortably integrate a host
> of choices into the airplane. But first, I need to achieve
> an understanding of the simple-ideas that go into
> our respective inventions . . . ingredients that drive
> recipes for success.
>
> 7) We have a common need to exercise a solid grasp
> of the same simple-ideas even if our respective inventions
> have no competitive features. The most pressing question
> for me is understanding the load-dump characteristics
> of our favorite alternators under conditions likely to
> be encountered in a typical installation on a Lycoming -
> spinning like a whirling dervish and subject to
> unloading under any condition between zero and full
> output with normal regulation. This means knowing the magnitude,
> source impedance and timing of the transient that occurs
> after sudden load removal at all corners of the
> operating envelope.
>
> 8) The very first experiment I plan to conduct after
> the alternator drive stand is running is based on
> the sketch at:
>
> On a 60A machine with battery disconnected,
> I'd get data plots of load dumps at 4, 6, 8, 10
> and 12KRPM for fixed load of 50A with a 10A dump,
> fixed load of 40A with 10A and 20A dumps, fixed
> of 30A and 10, 20 30A dumps . . . I think you'll see
> the pattern here.
>
> The goal would be to calculate/measure the peak
> voltage, total energy and duration of each overshoot
> event (or series of overshoots assuming the regulator
> control loop is poorly damped). I would probably
> set up to run external regulators (of the type
> normally installed inside) so that I could explore
> the differences between various regulators while
> holding the alternator constant.
>
> Obviously a big task to gather enough data to
> be reasonably sure we understand the majority of
> the fleet . . . assuming we discover wide variances.
>
> (9) The next tests would involve system behavior under
> runaway conditions. Artificially fail a regulator
> and plot dv/dt at the bus and di/dt at the battery
> with various fixed loads . . . one suite of plots
> with a fresh battery, another with a battery that
> has fallen to 1/2 capacity or less.
>
> Having this data on only one combination of
> alternator/regulator would set the order of magnitude
> for energies involved. Once the equipment for the
> testing is in place and the procedure tuned, it would
> probably take less than a half hour to test any other
> combination.
>
> I ran all these tests that supported products I designed
> for Beech and others many moons ago. But the only
> data acquisition we had then were storage 'scopes and
> chart recorders. You could "eyeball" the data for gross
> suitability to task but real energy studies were exceedingly
> difficult . . . they were never done. We can do a much
> better job today.
>
> The task is to characterize the dynamic response to
> load change for a normally functioning as well as
> a runaway alternator. The data collected would allow
> a designer to craft systems that deal quietly and
> capably with the voltages, currents and energies that
> are present during recovery from both a load-dump
> and hard-failure conditions.
>
> This was the kind of data I was hoping to gather
> some years back when there was discussion about
> you and Eric teaming on some sort of activity. I
> wasn't sure exactly what equipment you were going to
> have access to . . . or what testing satisfied
> curiosities for your project . . . but I had hopes
> of piggy-backing studies above if you didn't already
> have similar data.
>
> Do I presume that for your needs, no further
> investigation is necessary/useful to your task?
> Know that all of my own test results will be published
> on aeroelectric.com and that my equipment will be available
> to you (or anyone else in the OBAM aviation community)
> should new questions arise.
>
> I'm going to have Zach start stripping out the automotive
> test setup wiring from the test stand next week. We'll
> leave only the 3-phase motor drive wiring intact. We'll
> Z-12 and Z-13/8 architectures in the stand. I already
> have a small drive stand for second alternators up to 20A.
>
> I have a static phase converter to install in the
> big stand. We'll see we can get the motor and variable
> speed drives to run. That will be a BIG step. Not sure
> if we'll be able to do real testing before we have to
> pack up and move to M.L. I have a contractor running
> a fat 240 feeder to the shop at the same time we excavate
> for a new retaining wall at the back of the yard. So the
> heavy/dirty/ugly work should be behind us at both
> locations this summer.
>
> Bob . . .
>
>
>
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