Today's Message Index:
----------------------
1. 05:58 AM - pitot tube element (Jim Stone)
2. 06:13 AM - Re: pitot tube element (BobsV35B@aol.com)
3. 06:31 AM - Whelen Flasher RF Interference (Jeffrey Steenson)
4. 06:38 AM - It's not soap opera (Fergus Kyle)
5. 06:54 AM - Re: Points for discussion OVP/todays summary (Ken)
6. 06:57 AM - Re: pitot tube element (Jim Stone)
7. 07:02 AM - Re: Circuit breaker ratings for OVP (Eric M. Jones)
8. 07:19 AM - Re: Alternator characteristics (Gary Casey)
9. 07:40 AM - Re: Circuit breaker ratings for OVP (Paul Messinger)
10. 07:40 AM - Re: Re: DC Power Systems Dynamics - Breakers (Paul Messinger)
11. 07:40 AM - Re: Circuit breaker ratings for OVP (Paul Messinger)
12. 08:05 AM - Re: Circuit breaker ratings for OVP (Paul Messinger)
13. 09:09 AM - Diode question (Travis Hamblen)
14. 09:14 AM - Re: Re: Circuit breaker ratings for OVP (Ken)
15. 09:55 AM - Re: Diode question (Matt Prather)
16. 11:30 AM - Re: Diode question (Matt Prather)
17. 12:12 PM - Kudos To' Lectric Bob & Cohorts (J. Mcculley)
18. 01:31 PM - Re: Circuit breaker ratings for OVP (Eric M. Jones)
19. 03:05 PM - Re: Diode question (Ken)
20. 05:24 PM - Whelen power supply (Bill and Marsha)
21. 06:41 PM - Re: led dimmer question (CardinalNSB@aol.com)
Message 1
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| Subject: | pitot tube element |
--> AeroElectric-List message posted by: "Jim Stone" <jrstone@insightbb.com>
Does anyone know who can provide the part and or replace the heating element in
a pitot tube?
I've got a surplus AN 5812 unit set up for 115volts, I want to change that to 12
volts.
I would also be interested if anyone happens to have a 5812-12 unit they would
like to sell, contact me offline.
Thanks for the help,
Jim Stone
Harmon Rocket
do not archive
Message 2
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| Subject: | Re: pitot tube element |
--> AeroElectric-List message posted by: BobsV35B@aol.com
In a message dated 3/23/2005 7:59:17 A.M. Central Standard Time,
jrstone@insightbb.com writes:
Does anyone know who can provide the part and or replace the heating element
in a pitot tube?
I've got a surplus AN 5812 unit set up for 115volts, I want to change that
to 12 volts.
I would also be interested if anyone happens to have a 5812-12 unit they
would like to sell, contact me offline.
Thanks for the help,
Jim Stone
Harmon Rocket
Good Morning Jim,
Maybe we should be looking for an engine driven A/C generator system that
would supply that wild frequency 115 volt AC power that 'Lectric Bob has
mentioned?
It would open us up to a whole lot of neat surplus equipment.
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
Stearman N3977A
Brookeridge Airpark LL22
Downers Grove, IL 60516
630 985-8502
Message 3
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| Subject: | Whelen Flasher RF Interference |
--> AeroElectric-List message posted by: "Jeffrey Steenson" <jsteenson1@comcast.net>
I installed the Whelen flashing beacon atop the fin of my Murphy Rebel Elite
using unshielded wire. There is no stray radiation that my handheld was
able to pick up, but I am getting the distinctive sound of the flasher
firing through the panel radio.
Can this be corrected by using shielded wire from the flasher all the way
forward to the switch? or possibly for only the first portion of that run?
Or is it likely that I will beed a filter at the source.
This must be a very common problem with well established solutions!
Many thanks!
Jeffrey Steenson
ABQ, NM
Message 4
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| Subject: | It's not soap opera |
--> AeroElectric-List message posted by: "Fergus Kyle" <VE3LVO@rac.ca>
hello,
To go on record with an opinion, let the debate continue!
There's a lot to be learned just by scanning the remarks. There is nothing
to be learned by hiding the debate - except a myriad of childish spelling
mistakes and a lot of me-ing. Old Bob and others are right.
For those who cannot comprehend nor abide discussion - use your
DELE button and look for a games website.
Ferg
Europa A064
Message 5
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| Subject: | Re: Points for discussion OVP/todays summary |
--> AeroElectric-List message posted by: Ken <klehman@albedo.net>
Hi Jerry
You are golden and better than 98% of what is out there.
I know I'm happy with a "Spaceship One" although we are gradually
progressing to "Starship Enterprise" design ;)
Seriously there is a chance the OVM might get tweaked a bit to reduce
the chance of false trips and maybe specify a minimun circuit
resistance. Chances are that like me the resistance in you OVM wiring is
at the high end of what has been discussed - so again - no worries at
this point. It may be good practice to not route the OVP wiring too
close to your compass, magnetic sensors or glass instruments, or Hall
Effect current sensors. I'll bet you haven't done that anyway. There is
also a chance that new designs might gravitate towards non crowbar OV
protection but that doesn't mean I'll be removing what I have. Besides
where possible, I prefer a homebuilt device that I can test and repair
rather than a potted device with unknown components.
There is a very small chance that a OVM trip might cause a computer
reset for some specific items such as an aviation electronic ignition
that can't tolerate a momentary voltage drop but I judge that unlikely.
Most computers won't notice the momentary voltage drop that might
accompany a crowbar trip IMO. Some ignitions might miss a spark or fire
a weak spark but I'd be very surprised if the cpu itself noticed the trip.
It may give some peace of mind to add a transorb to any bus or power
input to a computer or expensive avionic device. There hasn't been
convincing need for that presented yet but I'll be doing that when the
weather warms up since it's easy and can be done for the cost of a cup
of Wet Coast designer coffee. Incidently mouser.com has the 5KP18A
devices in stock now although I'm using 1.5KP18A devices.
So far the discussion has re-inforced my happiness with my own
electrically dependant engine architecture that hardwires my alternators
to their respective batteries but I don't think that affects you. It
makes a lot of this discussion irrelevant if you don't have a battery
contactor. You do have a small external VR alternator which again is
good compared to a 100 amp internal VR automotive behemoth. So for the
time being - Motor On and Be Happy!
Ken
Jerry Isler wrote:
>--> AeroElectric-List message posted by: "Jerry Isler" <jlisler@alltel.net>
>
>As a lowly RV owner with a Vans 35 amp alternator, solid state external
>voltage regulator (VR-166?) and an AeroElectric crowbar overvoltage
>protection device wired in accordance with Bob's recommendation, what does
>all of this mean to me? If I experience an overvoltage condition and the
>crowbar OVP device trips the field breaker, are you saying the system is
>going to experience hundreds of excess amps from my 35 amp alternator for an
>fraction of a second and melt my lovely RV (and me) into oblivion? Obviously
>if there is an overvoltage condition on the system there is already a
>failure of some sort. Are you saying the crowbar OVP will make the failure
>worse?
>
>Jerry Isler
>RV4 N455J
>
>
Message 6
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| Subject: | Re: pitot tube element |
--> AeroElectric-List message posted by: "Jim Stone" <jrstone@insightbb.com>
Good one, but let's not go there.
Jim
----- Original Message -----
From: <BobsV35B@aol.com>
Subject: Re: AeroElectric-List: pitot tube element
> --> AeroElectric-List message posted by: BobsV35B@aol.com
>
>
> In a message dated 3/23/2005 7:59:17 A.M. Central Standard Time,
> jrstone@insightbb.com writes:
>
> Does anyone know who can provide the part and or replace the heating
> element
> in a pitot tube?
> I've got a surplus AN 5812 unit set up for 115volts, I want to change
> that
> to 12 volts.
> I would also be interested if anyone happens to have a 5812-12 unit they
> would like to sell, contact me offline.
> Thanks for the help,
> Jim Stone
> Harmon Rocket
>
>
> Good Morning Jim,
>
> Maybe we should be looking for an engine driven A/C generator system that
> would supply that wild frequency 115 volt AC power that 'Lectric Bob has
> mentioned?
>
> It would open us up to a whole lot of neat surplus equipment.
>
> Happy Skies,
>
> Old Bob
> AKA
> Bob Siegfried
> Ancient Aviator
> Stearman N3977A
> Brookeridge Airpark LL22
> Downers Grove, IL 60516
> 630 985-8502
>
>
>
Message 7
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| Subject: | Re: Circuit breaker ratings for OVP |
--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
Bob, et al.
It would seem improbably at best that a circuit breaker could be built to
survive an arbitrarily large overcurrent. As Paul has pointed out, the
addition of a small resistor will put this crowbar back into the barn.
The 1000% limit is what the device can take and still be per spec. The
"unlimited interrupting capacity"
I would like to suggest that some number of glitchy crowbar OVP's are due
to the "inadvertent recalibration" of the 5A circuit breaker--either through
testing (as we say--"to death"), or the use of a badly-treated circuit
breaker whose early life was questionable---perhaps having suffered from
electron abuse.
Some definitions from the industry: Ref:
http://www.trimaxcb.com/catalog/glossary.html
CURRENT RATING ---maximum current a circuit protector can carry continuously
without exceeding its performance limits. [There's the rating on the breaker
or fuse.]
INTERRUPT CAPACITY---the maximum amperage a circuit protector can safely
trip without evidence or risk of fire or electric shock during or after the
application of this maximum amperage. It is acceptable if, at this maximum
amperage, the circuit protector is rendered inoperable, providing it fails
in the open position and the leads or terminals are not damaged. [There's
the unlimited current.]
RESETTABLE OVERLOAD CAPACITY --- the maximum current the circuit protector
is capable of interrupting without damaging itself. [There's that 1000%.]
MUST-TRIP POINT ---Minimum current at which the circuit protector will trip
reliably. It is normally designated as the Must Trip Point and specified
as a percentage of overload versus trip time. [This is the circuit breaker
minimum trip current. It is a function of both current and time.]
I believed there was a need for non-crowbar OVP (called a "Linear OVM").
The one I make at Perihelion Design uses an LTC1696. But builders who want
to roll their own might want some other approach since the LTC part is a
six-legged surface mount IC the size of a grain of pepper.
One of the nice features of the Perihelion Design Linear OVM is that the
reset can be held in to over-ride the trip. I chewed on this for a while
before I decided that the pilot might be grateful for 18V (or so) if that
was what his failed alternator was putting out and if that was all he could
get.
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones@charter.net
"Everything you've learned in school as "obvious" becomes
less and less obvious as you begin to study the universe.
For example, there are no solids in the universe. There's
not even a suggestion of a solid. There are no absolute con-
tinuums. There are no surfaces. There are no straight lines."
- R. Buckminster Fuller
Message 8
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| Subject: | Re: Alternator characteristics |
--> AeroElectric-List message posted by: "Gary Casey" <glcasey@adelphia.net>
Paul said:
<<I have tested a battery with a constant current 40 amp supply. The battery
was a concord 25ah aircraft battery.
A battery that is fully charged acts more like a capacitor than a sink for
excess current. The test battery terminal voltage was well above 20V in
under 30 seconds and going up fast.
I have concluded (and the experts agree) that a battery will not clamp the
voltage if there is a lot of current that the battery does not need for
charging, it just goes into overcharge mode and away we go :-)
A battery is great as a capacitor for load dumps and other short term
overcurrents from the alternator but useless in the case of a long term
failure like a failed hi regulator, Thus the need for some sort of OVP.>>
That's the answer I was looking for - a "runaway" alternator will produce an
over-voltage condition in seconds, not milliseconds. If it were in minutes
then I would consider using the pilot as the over-voltage control (sees the
ov warning light and shuts off the alternator). If it were fractions of a
second then I don't see how the battery could absorb load dump surges. It
looks like the data shows the time available is less than a minute - a
little bit short to expect a pilot to react correctly, probably making
automatic OV protection prudent, but not mandatory. So I assume from all
this that if an OV event occurred and the alternator shut off that after the
battery voltage drooped the alternator could be turned back on and would NOT
immediately create another OV event until the battery became fully charged?
However, I for one am always VERY reluctant to turn something back on when I
don't know the reason it popped the breaker in the first place.
Gary Casey
And thanks to all for the open dialog - I always learn something.
Message 9
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| Subject: | Re: Circuit breaker ratings for OVP |
--> AeroElectric-List message posted by: "Paul Messinger" <paulm@olypen.com>
To me the OVP is only part of the system. As noted my suggestion of a 1/4
ohm resistor has side effects that need attenton. the following concerns are
possible before the addition of the addl resistor and very likely after its
addition.
Consider it takes 3-5 ms for the start of the crowbar in your OVP. OV can be
present during that time and its not clamped by the OVP.
Consider an internal regulated alternator. Here the OVP is unlikely to
completely clamp a OV condition and the internal regulator's OV protection
is typically set above 30 V as the intent is to protect the regulator.
Then consider a fast OVP action and a slow open contactor. After the CB
blows there is time between this event and the end of the opening of the
contactor for the OV to reappear for a short time.
ALL of the above is prevented with the proper application of Transorbs
across the bus on the bus side of the "B" lead contactor. Protection of the
alternator regulator (which seems necessary in the case of the Vans ND
alternators, well how knows?) is covered with a second set of Transorbs just
for the load dump as seen by the alternator internal regulator..
Thus proper use of transorbs and a OVP can cover 100% of any potential OV
condition and resulting tripping of the CB.
The transorbs must be chosen along with the OVP trip voltage so both work as
intended.
16V transorbs can keep the bus voltage to around 20V max and 18V transorbs
keep it to around 23V max. Depends on the current needed dumping etc but not
a unreasonable solution and low cost and simple to do.
I have tested this approach and it worked well in testing.
I agree with Bobs comments below.
Paul
----- Original Message -----
From: "Robert L. Nuckolls, III" <b.nuckolls@cox.net>
Subject: RE: AeroElectric-List: Circuit breaker ratings for OVP
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
> <b.nuckolls@cox.net>
>
> At 08:57 AM 3/23/2005 +1000, you wrote:
>
>>--> AeroElectric-List message posted by: "Kingsley Hurst"
>><khurst@taroom.qld.gov.au>
>>
>>Paul M,
>>
>>You said :-
>>As I have previously suggested there is a simple fix to those who are
>>using the crowbar OVP and that is to add a 1/4 ohm resistor in series that
>>will limit the current to 50 amps or less and will not prevent the proper
>>and
>>intended function of the OVP.
>>
>>What wattage are we talking about here please Paul or doesn't it matter
>>owing to the small duration of the high current event ?
>
>
> Is your alternator externally regulated? Then keep in mind that adding
> resistance in series with the ov protection module will reduce its
> ability to pull the field voltage down even BEFORE the breaker trips.
> In fact, adding this much resistance insures that the OV event will
> continue until the breaker opens. During the trip event, the series
> resistor will have to carry about 50A at about 10v for an instantaneous
> dissipation level of about 500 watts. Most wirewound resistor folks
> will rate their produces at 10x rated power for 5 seconds. So assuming
> a 10 watt, 0.25 ohm resistor will safely handle 100 watts for 5 seconds
> (current of 20A) this calculates to an Isquared*t value 20*20*5 or
> 2,000.
>
> Okay, for a 50A event, an Isquared*t of 2000 yields a maximum time
> of 2000/2500 or about .8 seconds. This suggests that a 10W resistor
> is plenty hefty enough to accomplish the task. A 5W resistor would
> be good for .4 seconds . . . also fine.
>
> See ALSR series wirewounds on Digikey at
>
> http://dkc3.digikey.com/PDF/T051/1026.pdf
>
> An ALSR5J-.25-ND (0.25 ohm, 5w) resistor is in stock and would
> cost you about $1.50
>
> If your alternator is internally regulated, then the OVM has no immediate
> effect on the runaway condition. Increasing the series resistance
> the OVM-14 only increases breaker opening time. However, given that
> the internally regulated alternator control system operates nicely through
> a 2A breaker, all you need to do is replace your existing breaker with
> a 2A sub-miniature breaker. See:
>
> http://bandc.biz/cgi-bin/ez-catalog/cat_display.cgi?7X358218#CB1
>
>
> These have an internal resistance of well OVER .25 ohms. 0.30 ohms
> in fact. This will have the same effect as adding series resistance
> to the OVM-14. Either way, the resistor cited above or replacing the
> breaker will have the desired effect.
>
> Bob . . .
>
>
>
Message 10
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| Subject: | Re: DC Power Systems Dynamics - Breakers |
--> AeroElectric-List message posted by: "Paul Messinger" <paulm@olypen.com>
Thanks for everything,
Paul
----- Original Message -----
From: "Robert L. Nuckolls, III" <b.nuckolls@cox.net>
Subject: Re: AeroElectric-List: Re: DC Power Systems Dynamics - Breakers
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
> <b.nuckolls@cox.net>
>
> At 05:09 PM 3/22/2005 -0800, you wrote:
>
>>--> AeroElectric-List message posted by: "Paul Messinger"
>><paulm@olypen.com>
>>
>>You have apparently missed my main point. Its not what you or I have done
>>with a few tests.
>>
>>We MUST do a worst case analysis of any and all parts used or recommended
>>and if specific parts are required they need top be specified. You have
>>specified parts for the OVP but not specified specific CB part #.
>
> Agreed
> snipped
> > I'll continue with the development of the white paper with
> exploration of suggested changes and repairs to errors noted.
> You are invited to comment on the continuing effort or not as you
> see fit. Your input to date has been thought provoking and
> helpful.
>
> Bob . . .
Message 11
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| Subject: | Re: Circuit breaker ratings for OVP |
--> AeroElectric-List message posted by: "Paul Messinger" <paulm@olypen.com>
The maximum breaking current is not the same as the maximum breaking current
with no damage.
10X is the typical specified breaking current with no damage. Above that
level the CB turns into a fuse. Somewhere, in this case, the 5 amp breaker
goed from a 50 amp current interuption to a fuse at 2000 amps interruption.
The purpose is circuit protection even at the expense of the CB sacrificing
its self tn its "final act" of protection.
It the CB good after breaking a 50 amp circuit the mggr says yes. What about
100 amps (20x) perhaps who knows. 2000amps you bet its gone.
Paul
----- Original Message -----
From: "Robert McCallum" <robert.mccallum2@sympatico.ca>
Subject: Re: AeroElectric-List: Circuit breaker ratings for OVP
> --> AeroElectric-List message posted by: Robert McCallum
> <robert.mccallum2@sympatico.ca>
>
> Bob;
>
> Although the "time to trip" charts stop at 1000% of the breakers rating,
> the specifications you have published here
>
> http://www.aeroelectric.com/Mfgr_Data/Breakers/Eaton_4200.pdf
>
> under interrupting capacity at 28 volts state that for a 4200 series
> breaker of 5 amp rating, the interrupting capacity is "unlimited" (seems
> a bit high?) Certainly more than 10X. Further the same spec sheet says
> that a 7.5 amp breaker is capable of interrupting 2000 amps. This is
> 266X its nominal rating. If you look at a 25 amp it's 80X nominal. I
> realize that this doesn't specify the number of times the breaker will
> survive these currents, but it does state that they are capable of
> taming currents of these magnitudes. How do these figures impact on the
> 10X theory and where does the 10X information show up in the
> specifications? In a parallel but totally different scenario, household
> breakers of 15 amp rating, to be certified for use in your home, (at
> least here in Canada) must be capable of interrupting 10,000 amps
> minimum. That's 667X nominal value. Unrelated, I know, but ----- These
> numbers and those stated by Eaton in the charts cited seem to be at odds
> with the 10X value. Yes????? No??????
>
> Bob McC
>
> Robert L. Nuckolls, III wrote:
>
>>--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
>><b.nuckolls@cox.net>
>>
>>Hmmmm . . . I note that the 10x rated limit for surviving repeated trips
>>seems to be an industry standard practice for most breakers offered.
>>One might guess that the limits to the plots in the graph I excerpted
>>at 1000% imply the same thing. I don't find it in words on the Eaton
>>data sheet like for most others on the 'net. I found some $low$ breakers
>>out there rated at only 6x for resetable trips.
>><snip>
>>Interesting. <snip>
>>Bob . . .
>>
>>
>
>
>
Message 12
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| Subject: | Re: Circuit breaker ratings for OVP |
--> AeroElectric-List message posted by: "Paul Messinger" <paulm@olypen.com>
Bob using a 2 amp CB is a good idea for the "B" lead contactor but when you
use a 2 amp CB the 1/4 ohm that reduces current to 50 amps is no longer
appropriate as the new max current is reduced from 50 amps to 20 amps.
So an additional resistor is still needed.
Paul
----- Original Message -----
From: "Robert L. Nuckolls, III" <b.nuckolls@cox.net>
Subject: RE: AeroElectric-List: Circuit breaker ratings for OVP
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
> <b.nuckolls@cox.net>
>
> At 08:57 AM 3/23/2005 +1000, you wrote:
> If your alternator is internally regulated, then the OVM has no immediate
> effect on the runaway condition. Increasing the series resistance
> the OVM-14 only increases breaker opening time. However, given that
> the internally regulated alternator control system operates nicely through
> a 2A breaker, all you need to do is replace your existing breaker with
> a 2A sub-miniature breaker. See:
>
> http://bandc.biz/cgi-bin/ez-catalog/cat_display.cgi?7X358218#CB1
>
>
> These have an internal resistance of well OVER .25 ohms. 0.30 ohms
> in fact. This will have the same effect as adding series resistance
> to the OVM-14. Either way, the resistor cited above or replacing the
> breaker will have the desired effect.
>
> Bob . . .
Message 13
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--> AeroElectric-List message posted by: "Travis Hamblen" <TravisHamblen@cox.net>
I am using Z-11 plan and have a couple questions that you guys will
definitely know about. First, I am using the suggested steering diode
between the main and essential bus (using the heat sink). The question is
that because of the amperage I am sending through this diode ( < 25a but
sometimes > 20a) I will be using 10awg wire which means I can't use a fast
on terminal because they don't make them for awg that large. SO would a
good alternative be to solder the wires to the fast on connectors on the
diode? If I did this would it be just as secure, I was concerned that with
all the vibration in an RV that the solder could break away after a while.
I would prefer to use a fast on, but haven't been able to find fast ons for
awg smaller than 14awg; if someone has a source for these please let me
know!
The second question is about the fuse that the steering diode calls for.
The diode is only rated up to a max of 25a and this is a perfect match for
my system. However, it also calls for the use of a breaker or fuse on the
two wires going to the main bus. I was thinking of using an automotive
style inline fuse that would use a 30a standard 1/4" blade type fuse. Is
there a better way or will the inline fuse work just fine?
Thanks,
Travis
RV-7A wiring
--
Message 14
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| Subject: | Re: Circuit breaker ratings for OVP |
--> AeroElectric-List message posted by: Ken <klehman@albedo.net>
But is it an arbitrarilly large current at the specified voltages and
with wires that can reasonably be attached to the device? One of the
examples mentioned about 35 miliohms resistance for the breaker. Well if
a 12volt battery is pulled down to say 10 volts then you simply can't
get more than 10 / 0.035 =286 amps even with a zero impedance (at 10
volts) battery and zero resistance wires and connectors! But it would be
less with real wires, real connectors, and a real battery. OK double
that for a 24 volt system but it still isn't arbitrarilly large.
N'other thing worth consideration might be reliability and the failure
modes of OVP devices. A crowbar that does nothing in normal ops might
have a higher probability of failing passively in normal operations
compared to a device that must continuously conduct field curent to keep
the alternator running??
Ken
Eric M. Jones wrote:
>--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
>
>Bob, et al.
>
>It would seem improbably at best that a circuit breaker could be built to
>survive an arbitrarily large overcurrent. As Paul has pointed out, the
>addition of a small resistor will put this crowbar back into the barn.
>
>
>snip
Message 15
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| Subject: | Re: Diode question |
--> AeroElectric-List message posted by: "Matt Prather" <mprather@spro.net>
Hi Travis,
A few questions for your questions...
> --> AeroElectric-List message posted by: "Travis Hamblen"
> <TravisHamblen@cox.net>
>
> I am using Z-11 plan and have a couple questions that you guys will
> definitely know about. First, I am using the suggested steering diode
> between the main and essential bus (using the heat sink). The question
> is that because of the amperage I am sending through this diode ( < 25a
> but sometimes > 20a) I will be using 10awg wire which means I can't use
For what duration does your power budget show that you will be greater
than 20A. What's the biggest consumer in that 20A budget? Actually, do
you have a list of components on the e-buss and what each item consumes?
The reason I am picking this is that 20A seems like a lot.
> a fast on terminal because they don't make them for awg that large. SO
> would a good alternative be to solder the wires to the fast on
> connectors on the diode? If I did this would it be just as secure, I
> was concerned that with all the vibration in an RV that the solder could
> break away after a while. I would prefer to use a fast on, but haven't
> been able to find fast ons for awg smaller than 14awg; if someone has a
> source for these please let me know!
If it turns out that you really need 14awg and can't find the right terminals
for it (aren't the yellow terminals 14-16awg?), with proper strain relief,
soldering
is a good option. My only concern is that you use a good iron and good
technique
so that you don't seriously overheat the package while soldering to it.
Probably
not an issue, but just something to think about.
>
> The second question is about the fuse that the steering diode calls for.
> The diode is only rated up to a max of 25a and this is a perfect match
> for my system. However, it also calls for the use of a breaker or fuse
> on the two wires going to the main bus. I was thinking of using an
> automotive style inline fuse that would use a 30a standard 1/4" blade
> type fuse. Is there a better way or will the inline fuse work just
> fine?
I have never seen an inline style fuse holder that I thought was particularly
neat or secure. They seem barely adequate for adding a CB radio to your
cousin's pickup truck. I probably just haven't seen the right holder. Show
me.
I think this might be a reasonable application for a fusible link.
>
> Thanks,
> Travis
> RV-7A wiring
>
> --
>
Regards,
Matt-
VE N34RD, C150 N714BK
Message 16
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--> AeroElectric-List message posted by: "Matt Prather" <mprather@spro.net>
Hi Travis,
Including some of these items on the e-bus seems like a bit of a deviation
from the philsophy that I understand. Care to share your thoughts on this?
I wonder about the engine monitor, Flaps, Fuel Boost. It doesn't seem that
any of these items contribute very much to enroute capability. The items
needed are those which help keep the airplane right side up, on course, and
out of the rocks. I thought that things required to keep the engine running
go on the battery bus. I say the xponder and com go on the main bus, but
they
are such small consumers that you could go either way with them. Sometimes
it's comforting, quite a bit more convenient, and safer to be able to talk
and take
radar vectors.
None the less, all of this is somewhat academic, since you have already found
components that allow you to wire the system the way you want.
On an RV, do you consider the flaps to be a necessity?
The fuse holder you posted the link to is okay - about what I thought. My
only
gripes are that it doesn't have any mounting lugs, and that since it has
wires
already attached, you have to introduce two extra sets of connections in
order
to wire it up. Can you change the fuse without putting undue strain on
the wire
connections?
Which part of the fusible link don't you like?
Regards,
Matt-
VE N34RD, C150 N714BK
> e-bus is the following:
>
> Dynon EFIS & Engine Monitor
> EKP IV GPS
> XCOM VHF
> Xponder
> Auto Pilot
> Flaps
> Fuel boost
> Trim
> Interior lighting
>
> I know I wouldn't be using half of these things on a constant basis in
> the event of an elec problem, but I have reasons for having each of
> these on the e-bus. As it turns out, I was just able to find some
> faston connectors for 10awg, so I won't have to solder anything. As for
> the inline fuse, I found a very good quality (marine grade) setup that I
> will use; I just don't like the whole fusible link thing, kind of scary
> to me. Check out the below link (link might break or wrap in e-mail):
>
> http://www.go2marine.com/g2m/action/GoBPage/id/85194F/flat_fuse_holder__30_a
> mp_sierra.html
>
> Travis
>
Message 17
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| Subject: | Kudos To' Lectric Bob & Cohorts |
--> AeroElectric-List message posted by: "J. Mcculley" <mcculleyja@starpower.net>
Just my 2 cents ($2 with inflation)! Reading the current issue of FLYING
Magazine, April 2005, page 70, again reminds me of all that Bob Nuckolls
and the other knowledgeable contributors on this list have done to
educate us OBAM participants so that we don't remain stuck with the
faulty architecture of the SPAM CAN products. Although this referenced
article is not truly a Dark-N-Stormy-Nite story, it was only one click
less, and identifies how easily the lack of optimum electrical
architecture and instrumentation can negatively interact with the human
factors side of piloting and facilitate unnecessary outcomes. In this
case it was about alternator failure not involving sophisticated
overvoltage matters but only simple solutions that could have prevented
such an event. Thanks to Bob and this list there should be no OBAM
aircraft subject to the same situation. I'm confident the current very
active debates on OV design, alternators and Load Dump needs to run its
course out in the open so that we will all eventually understand the
details and better appreciate the final scientifically derived
recommendations that are sure to come. Let the battles continue!
Jim McCulley, faithful reader & Tailwind Driver
DO NOT ARCHIVE!
Message 18
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| Subject: | Re: Circuit breaker ratings for OVP |
--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
--> AeroElectric-List message posted by: Ken <klehman@albedo.net>
>>--> AeroElectric-List message posted by: "Eric M. Jones"
<emjones@charter.net>
>>
>>It would seem improbably at best that a circuit breaker could be built to
>>survive an arbitrarily large overcurrent. As Paul has pointed out, the
>>addition of a small resistor will put this crowbar back into the barn.
>>snip
>But is it an arbitrarilly large current at the specified voltages and
>with wires that can reasonably be attached to the device? One of the
>examples mentioned about 35 miliohms resistance for the breaker. Well if
>a 12volt battery is pulled down to say 10 volts then you simply can't
>get more than 10 / 0.035 =286 amps even with a zero impedance (at 10
>volts) battery and zero resistance wires and connectors! But it would be
>less with real wires, real connectors, and a real battery. OK double
>that for a 24 volt system but it still isn't arbitrarilly large.
Ken,
I didn't mean infinitely large. I meant some amount over the 1000% limit
specified by the CB manufacturer. The point is that Bob's white paper
assumed you could extend the curves...and well...I don't think you can.
>N'other thing worth consideration might be reliability and the failure
>modes of OVP devices. A crowbar that does nothing in normal ops might
>have a higher probability of failing passively in normal operations
>compared to a device that must continuously conduct field curent to keep
>the alternator running??
Point taken, but the Linear OVP should be as good as the regulator, the ECU,
and the prop bolts. I mention installing a MOM-OFF-ON switch to over-ride
everything if one wants to.
I'd put the Linear OVM reliability up again the crowbar and breaker any
time. Reliability is fundamentally what this argument is about.
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones@charter.net
Teamwork: " A lot of people doing exactly what I say."
(Marketing exec., Citrix Corp.)
Message 19
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| Subject: | Re: Diode question |
--> AeroElectric-List message posted by: Ken <klehman@albedo.net>
Yellow PIDG faston terminals are available from digi-key in
(min.quantity 10) and work fine on 10 and 12 awg wire.
Ken
Travis Hamblen wrote:
>--> AeroElectric-List message posted by: "Travis Hamblen" <TravisHamblen@cox.net>
>
>I am using Z-11 plan and have a couple questions that you guys will
>definitely know about. First, I am using the suggested steering diode
>between the main and essential bus (using the heat sink). The question is
>that because of the amperage I am sending through this diode ( < 25a but
>sometimes > 20a) I will be using 10awg wire which means I can't use a fast
>on terminal because they don't make them for awg that large. SO would a
>good alternative be to solder the wires to the fast on connectors on the
>diode? If I did this would it be just as secure, I was concerned that with
>all the vibration in an RV that the solder could break away after a while.
>I would prefer to use a fast on, but haven't been able to find fast ons for
>awg smaller than 14awg; if someone has a source for these please let me
>know!
>
>The second question is about the fuse that the steering diode calls for.
>The diode is only rated up to a max of 25a and this is a perfect match for
>my system. However, it also calls for the use of a breaker or fuse on the
>two wires going to the main bus. I was thinking of using an automotive
>style inline fuse that would use a 30a standard 1/4" blade type fuse. Is
>there a better way or will the inline fuse work just fine?
>
>Thanks,
>Travis
>RV-7A wiring
>
>
>
Message 20
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| Subject: | Whelen power supply |
--> AeroElectric-List message posted by: "Bill and Marsha" <docyukon@ptcnet.net>
I have a whelen strobe power supply with MS Cannon conectors. Can anyone
tell me the pin out and coler code to connect up to whelen flash tubes?
Message 21
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| Subject: | Re: led dimmer question |
--> AeroElectric-List message posted by: CardinalNSB@aol.com
Hello:
I have been playing with the LM 317 adjustable voltage regulator
12 volt positive input to the LM 317
led positive lead(s) all connected to the output of the LM 317
common ground for led leads to battery negative
The brightness of the light is based on the (adjusted) voltage, whether 1 or
more leds are connected. So, this will dim leds, brightness is stable,
whether 1 or more leds are in the system.
However, my Garmil 300xl outputs 12 volt + per annnciator light so the LM
317 isn't appropriate. I would need a separate LM 317 for each light circuit
and a way to control each LM 317 at the same time.
Is there a similar product that the common ground from the leds would be the
input and the chassis ground would be the output that would maintain the
reduced voltage?
Is this what the LM 137 does?
That is, the 12v+ from the gps box would go to the led, the negative leg of
the various leds would be connected in common to the input of the LM 137, and
the output of the LM 137 would be grounded. Sort of a LM 317 setup but on
the "downside" leg of the leds.
Thanks for the help. Skip Simpson.
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