Today's Message Index:
----------------------
1. 12:26 AM - Re: Re: Subaru z-figure (Hans Teijgeler)
2. 06:28 AM - Re: Re: Subaru z-figure (Mickey Coggins)
3. 06:45 AM - Re: Using a 115 volt 400 hz device in a 12 volt (Jerzy Krasinski)
4. 07:17 AM - Re: Re: StripMaster Wire Strippers (Robert L. Nuckolls, III)
5. 07:19 AM - Re: Using a 115 volt 400 hz device in a 12 volt airplane (Craig P. Steffen)
6. 07:20 AM - Re: Sudden overwhelming signal on radio? (Dj Merrill)
7. 08:28 AM - Re: Using a 115 volt 400 hz device in a 12 (Richard Riley)
8. 08:42 AM - Re: Using a 115 volt 400 hz device in a 12 volt airplane (BobsV35B@aol.com)
9. 09:15 AM - Re: Using a 115 volt 400 hz device in a 12 volt airplane (cgalley)
10. 09:21 AM - Re: Using a 115 volt 400 hz device in a 12 volt airplane (BobsV35B@aol.com)
11. 10:34 AM - Re: Using a 115 volt 400 hz device in a 12 (rd2@evenlink.com.volt.airplane)
12. 01:52 PM - Re: White Paper on Crowbar OV Protection (Eric M. Jones)
13. 01:56 PM - Re: Using a 115 volt 400 hz device in a 12 volt airplane (cgalley)
14. 02:02 PM - Re: Using a 115 volt 400 hz device in a 12 volt airplane (cgalley)
15. 02:10 PM - Re: Using a 115 volt 400 hz device in a 12 volt airplane (BobsV35B@aol.com)
16. 03:49 PM - Re: Using a 115 volt 400 hz device in a 12 volt (Robert McCallum)
17. 06:49 PM - Re: Re: White Paper on Crowbar OV Protection (Mike Nellis)
18. 07:20 PM - Re: Re: White Paper on Crowbar OV Protection (George Braly)
19. 07:50 PM - Re: Re: White Paper on Crowbar OV Protection (Robert McCallum)
20. 09:28 PM - Re: Re: White Paper on Crowbar OV (Robert L. Nuckolls, III)
21. 09:40 PM - Re: Using a 115 volt 400 hz device in a 12 (Robert L. Nuckolls, III)
Message 1
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| Subject: | Re: Subaru z-figure |
--> AeroElectric-List message posted by: "Hans Teijgeler" <hans@jodel.com>
Jon,
Your requirements exactly match mine. Strictly VFR, Subaru engine and tough
luck for ATC, but as soon as my alternator dies the radio will be switched
off, no lights, no strobe, no tpx, no electric flaps, no electric trim, just
the engine to feed from two batteries.
I've ended up with a very simple diagram:
Battery A feeds pump A, computer A and the main bus.
Battery B feeds pump B, computer B and the starter
One alternator tops off both batteries through some diodes
No crossfeeding, no E-bus, no complexity. I know that I am throwing away a
lot of flexibility, I know that a triple failure might shut me down
(alternator, battery A and computer B broken = glider), but I can live with
that. The reduced complexity makes up for that- for me.
Thanks Bob for the preview. The diagram makes a lot of sense if you want to
keep alive more than the engine alone. Like with Jon, it simply is overkill
for my requirements.
Hans
> -----Oorspronkelijk bericht-----
> Van: owner-aeroelectric-list-server@matronics.com [mailto:owner-
> aeroelectric-list-server@matronics.com] Namens Jon Finley
> Verzonden: dinsdag 15 maart 2005 17:48
> Aan: aeroelectric-list@matronics.com
> Onderwerp: RE: AeroElectric-List: Re: Subaru z-figure
>
> --> AeroElectric-List message posted by: "Jon Finley" <Jon@finleyweb.net>
>
>
> Sort of opportune moment to jump into this thread Ive been trying to find
> the time to compose some intelligent questions about a simple electron-
> dependent-engine system (Subaru).
>
> After studying the Z diagrams (I've not yet studied these sneak-peak
> diagrams), I came up came up with the system posted on my website
> (http://www.finleyweb.net/default.asp?id=131). This was designed and
> constructed more than a year ago. Since this time Ive learned a lot by
> lurking here and now understand that my system has a number of
> weaknesses/problems (which probably means that are more things that I dont
> even know about yet).
>
> My biggest issue/hurdle is that the relevant Z diagrams seem overly
> complicated for my simple system. I do not have a highly complex airplane
> nor do I have a difficult mission profile. While I am an IFR pilot, I know
> that my airplane is strictly VFR. When I detect an electrical problem,
> everything in the airplane is going to be shutdown. The engine keeps
> running from the battery and I land (within an hour). I dont NEED a
> radio, transponder, gauges, five-hour range, etc... just need the engine
> to keep running for a bit. I could probably babble on for a long time
> about this but my point (really a request) is that I would really like to
> see a simple system for a Subaru.
>
> Thanks Bob!
>
> Jon Finley
> N90MG Q2 - Subaru EJ-22 DD - 467 Hrs. TT
> Apple Valley, Minnesota
> http://www.FinleyWeb.net/Q2Subaru
>
>
> ---------- Original Message ----------------------------------
> From: "Robert L. Nuckolls, III" <b.nuckolls@cox.net>
> Date: Tue, 15 Mar 2005 09:52:31 -0600
>
> >--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
> <b.nuckolls@cox.net>
> >
> >At 04:34 PM 3/15/2005 +0100, you wrote:
> >
> >>--> AeroElectric-List message posted by: "Hans Teijgeler"
> <hans@jodel.com>
> >>
> >>Bob,
> >>
> >>I've downloaded a whole bunch from your web site, but the Z figures in
> those
> >>downloads do not include a Z-19. Could you please give me a steer?
> >>
> >>Thanks
> >
> >This is a pending rev 11 addition. Sneak peek at:
> >
> >http://www.aeroelectric.com/PPS/Architecture/Zfigs_K_5.pdf
> >
> > Bob . . .
>
>
>
>
>
Message 2
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| Subject: | Re: Subaru z-figure |
--> AeroElectric-List message posted by: Mickey Coggins <mick-matronics@rv8.ch>
I'm happy to say that the diagram I came up with for my
electrically dependent engine, based on the information
I got from Bob's book, and this list, looks essentially
like Bob's new Z-19. Kind of makes me think that I may
have actually learned something these past few months!
I have a somewhat related question. Could there be any
increase in risk having two batteries run in parallel?
One battery taking out the other under some strange
circumstance?
Thanks,
Mickey
--
Mickey Coggins
http://www.rv8.ch/
#82007 Wiring
Message 3
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| Subject: | Re: Using a 115 volt 400 hz device in a 12 volt |
airplane
--> AeroElectric-List message posted by: Jerzy Krasinski <krasinski@provalue.net>
Tony Johnson wrote:
>--> AeroElectric-List message posted by: "Tony Johnson" <tonyjohnson@cfl.rr.com>
>
>I have a pitot tube that is wired for a 115 volts at 400 hz. I would like
>to use it on my RV8A, which will have a 12 volt system.
>
>
>I applied 110v house current to the tube, using a dimmer switch set at the
>lowest setting. The tube heated up. I was afraid to increase the power to
>it.
>
>
>My plan is to acquire an adjustable resistor, set it for high resistance,
>and apply 12volts through it to the tube, probably with a fuse inline
>between the resistor and tube.
>
>
>I would appreciate any input as to how to arrange to use the tube on my 12
>volt system.
>
>
>Tony Johnson
>
>RV8A Orlando
>
>
>
>
Tony,
At 110V heater powered from 12V is useless, it will produce roughly 1%
of its rated power. Do not bother with trying to get it working using 12V.
You can power it from one of cheap commercial inverters 12V to
110V/60Hz. The frequency is irrelevant in case of a heater. But check if
the inverter does not make radio interference.
Jerzy
Message 4
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| Subject: | Re: StripMaster Wire Strippers |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <b.nuckolls@cox.net>
At 05:57 PM 3/15/2005 -0700, you wrote:
>--> AeroElectric-List message posted by: Sean Stephens <schmoboy@cox.net>
>
>Sorry, found this link and was wondering if it is a good price and the
>correct model...
>
><http://www.goodmart.com/products/86241.htm>
>
>Thanks...
Yes, this is the benchmark stripper for Tefzel/Teflon insulated
wires. Anything under $150 is probably a good deal. Alternatively,
I have fabricated my own clones by salvaging the dies out of
strippers with broken handles and installing them in Radio Shack
clones of the Ideal Stripmaster handles (about $13.00). You can
buy a new die set from the same company at:
http://www.goodmart.com/products/86079.htm
for about $82 and put them into an RS handle for under $100
total.
You can get "real" Stripmaster handles off ebay. When fitted
with the el-cheeso dies, they go pretty cheap. See:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=26229&item=7500103375&rd=1&ssPageName=WDVW
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=66989&item=7500963130&rd=1&ssPageName=WDVW
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=66989&item=7500572228&rd=1&ssPageName=WDVW
Here's an auction on a pair of strippers described to
have type E (tefzel/teflon) dies:
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=4535940899&category=26436&sspagename=WDVW
But if push comes to the big shove, one can learn to strip Tefzel
wire with a pair of flush cutters . . .
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=66990&item=3880590926&rd=1
See
http://aeroelectric.com/articles/strippers/strippers.html
Bob . . .
Message 5
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| Subject: | Re: Using a 115 volt 400 hz device in a 12 volt airplane |
--> AeroElectric-List message posted by: "Craig P. Steffen" <craig@craigsteffen.net>
> I have a pitot tube that is wired for a 115 volts at 400 hz. I would like
> to use it on my RV8A, which will have a 12 volt system.
Now I'm curious. What power system produces 115 VAC at 400 Hz?
> My plan is to acquire an adjustable resistor, set it for high resistance,
> and apply 12volts through it to the tube, probably with a fuse inline
> between the resistor and tube.
Why don't you just get a heater that's designed to work at 12V?
Dropping the voltage down with a series resistor means that you're
dumping a lot of the power into the resistor, not the heater.
Craig Steffen
--
craig@craigsteffen.net
public key available at http://www.craigsteffen.net/GPG/
current goal: use a CueCat scanner to inventory my books
career goal: be the first Vorlon Time Lord
Message 6
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| Subject: | Re: Sudden overwhelming signal on radio? |
--> AeroElectric-List message posted by: Dj Merrill <deej@thayer.dartmouth.edu>
Dr. Andrew Elliott wrote:
> I recently installed an ICS-Plus radio in my AA-1. I have been
> relatively happy with it, but today on a return flight from Mexico,
> while cruising along FD&H at 10.5 about 30 minutes in, it was suddenly
> overwhelmed by what sounded to me to be broadband noise. It did not
> seem to be alternator dependent, as I switched off the alternator and
> changed RPMs with no apparent effect.
Hi Andy,
I was flying through South Carolina the other day, and
for at least a solid 5 minutes I was clearly picking up a
broadcast radio station. My guess is that the frequency I
had on the COM radio was a harmonic of the radio broadcast
frequency, or the internal oscillators of the radio
were picking up the broadcast signal directly. I was at
7500 feet.
If it does not do it all the time my guess is a local
geographic issue - can you try flying over the same place
again with your radio set to the same freq and see
it you can repeat it?
-Dj
--
Dj Merrill
deej@thayer.dartmouth.edu
"TSA: Totally Screwing Aviation"
Message 7
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| Subject: | Re: Using a 115 volt 400 hz device in a 12 |
volt airplane
--> AeroElectric-List message posted by: Richard Riley <Richard@Riley.net> volt
airplane
At 07:19 AM 3/16/05, you wrote:
>--> AeroElectric-List message posted by: "Craig P. Steffen"
><craig@craigsteffen.net>
>
> > I have a pitot tube that is wired for a 115 volts at 400 hz. I would like
> > to use it on my RV8A, which will have a 12 volt system.
>
>Now I'm curious. What power system produces 115 VAC at 400 Hz?
They're very common in military aircraft.
Message 8
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| Subject: | Re: Using a 115 volt 400 hz device in a 12 volt airplane |
--> AeroElectric-List message posted by: BobsV35B@aol.com
In a message dated 3/16/2005 10:29:35 A.M. Central Standard Time,
Richard@RILEY.NET writes:
>
>Now I'm curious. What power system produces 115 VAC at 400 Hz?
They're very common in military aircraft.
Good Morning All,
As long as the subject has been broached, are there any efficient, light
weight, low cost converters available that will supply 115 volt 400 cycle
current from twelve or twenty four volts DC?
The ones we had on the DC-6s and DC-7s must have weighed a ton!
Well, maybe only fifty pounds or so, but way to big for a small airplane.
Anything better been developed in the last sixty years?
I have very nice oscillating beacon that uses that current.
It sure would be nice to be able to drive it from twenty-four volt DC power.
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
Stearman N3977A
Brookeridge Airpark LL22
Downers Grove, IL 60516
630 985-8502
Message 9
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| Subject: | Re: Using a 115 volt 400 hz device in a 12 volt airplane |
--> AeroElectric-List message posted by: "cgalley" <cgalley@qcbc.org>
They make solid state converters. I have one for a remote compass system.
Very small and weighs very little.
----- Original Message -----
From: <BobsV35B@aol.com>
Subject: Re: AeroElectric-List: Using a 115 volt 400 hz device in a 12 volt
airplane
> --> AeroElectric-List message posted by: BobsV35B@aol.com
>
>
> In a message dated 3/16/2005 10:29:35 A.M. Central Standard Time,
> Richard@RILEY.NET writes:
>
>>
>>Now I'm curious. What power system produces 115 VAC at 400 Hz?
>
> They're very common in military aircraft.
>
>
> Good Morning All,
>
> As long as the subject has been broached, are there any efficient, light
> weight, low cost converters available that will supply 115 volt 400 cycle
> current from twelve or twenty four volts DC?
>
> The ones we had on the DC-6s and DC-7s must have weighed a ton!
>
> Well, maybe only fifty pounds or so, but way to big for a small airplane.
> Anything better been developed in the last sixty years?
>
> I have very nice oscillating beacon that uses that current.
>
> It sure would be nice to be able to drive it from twenty-four volt DC
> power.
>
> Happy Skies,
>
> Old Bob
> AKA
> Bob Siegfried
> Ancient Aviator
> Stearman N3977A
> Brookeridge Airpark LL22
> Downers Grove, IL 60516
> 630 985-8502
>
>
>
Message 10
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| Subject: | Re: Using a 115 volt 400 hz device in a 12 volt airplane |
--> AeroElectric-List message posted by: BobsV35B@aol.com
In a message dated 3/16/2005 11:16:42 A.M. Central Standard Time,
cgalley@qcbc.org writes:
They make solid state converters. I have one for a remote compass system.
Very small and weighs very little.
Good Morning Cy,
How much output, how much weight, how much cost and where can it be
purchased!
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
Stearman N3977A
Brookeridge Airpark LL22
Downers Grove, IL 60516
630 985-8502
Message 11
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| Subject: | Re: Using a 115 volt 400 hz device in a 12 |
volt airplane
--> AeroElectric-List message posted by: rd2@evenlink.com volt airplane
-----snip-----------------
They make solid state converters. I have one for a remote compass system.
Very small and weighs very little.
----snip------------------
They?
Sorry, I may have missed something, or it got somehow truncated. Was there
an URL with the post?
Rumen
Message 12
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| Subject: | Re: White Paper on Crowbar OV Protection |
--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
Robert, et al.
Re:
http://www.aeroelectric.com/articles/Crobar_OV_Protection/Crowbar_White_Paper.pdf
About 5000 years ago the Chinese had remarkable scientific techniques. But
somewhere along the way they decided that an experiment isolated from the
rest of the world was simply not valid, because it was believed that
everything influenced everything else. Ahem....but I digress........maybe.
The White Paper skirts the key issue which is: Why bother using the crowbar
technique when it has been abandoned by the rest of the entire cosmic
universe for systems such as this? I have in my hand the data sheets for the
MC3309X line of Motorola alternator voltage regulator chips (the most recent
of which--MC33099-- contains adaptive logic!...but I digress). Can you guess
what Motorola uses to terminate the field winding when bad things happen?
There are about a hundred bazillion of these in service (and sampling the
product stream to get one is like drinking from a firehose....but I
digress). No crowbars here bubela.
Nobody argues that a crowbar works, it just isn't used anymore because
better methods are available. For those who MUST have a crowbar do it this
way:
http://www.periheliondesign.com/downloads/NOOVP.pdf But unless the system
requirement is to make the whole circuit dead in a wink, nobody does this
anymore.
Now to the White Paper:
1) Cover page is okay except "Over Voltage" should be hyphenated.
"...Comprised of..." is not English.
2) What is this drawing? Nobody has an electrical system as shown. The
Klixon 7274 is the way-fastest part in the series. What is the big diode?
Why not use the AE Crowbar here instead of whatever stand-in we see? [Insert
eight-dozen other quibbles here.] If RAC has a spare TDS210 in the closet
I'd jeeze I'd love to have one. But I digress.....
3) Okay...short attention span. The rest of the report massages the figures
a bit but arrives at the conclusion that maybe 263A or so blasts through the
little 5A Klixon 7274 like a photon torpedo.
Discussion: The Klixon 7274 is not rated for 14.5 V trips of this magnitude.
While it is rated as "Unlimited Amps at 28V", can we therefore assume that
this makes 14.5V a piece of cake? Hardly; from 8-16 volts is a kind of
neverland for electrical contacts---to high for gold and too low for
silver--the voltages/trip characteristics do not scale. The TI/Klixon graphs
show the maximum breaking capacity at 28V is 1000% (10X) rated and 0.10 to
0.40 S. NOT 263/5= 5260% and 15 mS. Assuming we do this anyway--how many
shots is the breaker now good for? 3? 10? 1000? Who knows?
Discussion: The alternator shown....oops, who stole the darned alternator?
The alternator does something very bad when crowbarred. It puffs up its
little cheeks and chest preparing to spew out more electrons, but the next
second, loadless, it is disappointed and does the Technicolor yawn off the
back porch. This is my explanation for Load Dump which is better than
Paul's, but I digress....The alternators contribution to the OVP episode is
not strictly a DC matter.
Anyway, I suggest that the test setup in not a good representation of what
is happening in the system.
Finally....whew....we get back to the main question---Why bother hammering
the electrical system with a crowbar when you don't have to? Let's have some
common sense.
With great respect...and sorry about the humor...it's those pills the doctor
makes me take.
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones@charter.net
"The beginning of the end is marked by replacement of experience and common
sense with policy and procedures."
-- R. L. Nuckolls III
Message 13
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| Subject: | Re: Using a 115 volt 400 hz device in a 12 volt airplane |
--> AeroElectric-List message posted by: "cgalley" <cgalley@qcbc.org>
I may have spoken too soon. Went back into my shop and pulled it out. It is
by Aircraft instrument and Development. It was purchased for $37 about 1980
by a friend who gave it to me.
Label says P/N 23-1100-4amps, input 14 VDC Output 26 VAC 400 hz 10 VA
Aircraft Inst. & Dev. Inc
317 E Lewis, Wichita, Kansas
The box is 2x1.5x2.5inches which is a far cry from the big war surplus
inverters. for the compass system.
It isn't what you want but I have a feeling that there is a box that will.
I found this same Box listed at http://www.mcico.com/pdf/md26.pdf with a
drawing.
Cy Galley - Chair,
AirVenture Emergency Aircraft Repair
A Service Project of Chapter 75
EAA Safety Programs Editor - TC
EAA Sport Pilot
----- Original Message -----
From: <BobsV35B@aol.com>
Subject: Re: AeroElectric-List: Using a 115 volt 400 hz device in a 12 volt
airplane
> --> AeroElectric-List message posted by: BobsV35B@aol.com
>
>
> In a message dated 3/16/2005 11:16:42 A.M. Central Standard Time,
> cgalley@qcbc.org writes:
>
> They make solid state converters. I have one for a remote compass
> system.
> Very small and weighs very little.
>
>
> Good Morning Cy,
>
> How much output, how much weight, how much cost and where can it be
> purchased!
>
> Happy Skies,
>
> Old Bob
> AKA
> Bob Siegfried
> Ancient Aviator
> Stearman N3977A
> Brookeridge Airpark LL22
> Downers Grove, IL 60516
> 630 985-8502
>
>
>
Message 14
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| Subject: | Re: Using a 115 volt 400 hz device in a 12 volt airplane |
--> AeroElectric-List message posted by: "cgalley" <cgalley@qcbc.org>
Found the price $374 for the little box I have.
----- Original Message -----
From: <BobsV35B@aol.com>
Subject: Re: AeroElectric-List: Using a 115 volt 400 hz device in a 12 volt
airplane
> --> AeroElectric-List message posted by: BobsV35B@aol.com
>
>
> In a message dated 3/16/2005 11:16:42 A.M. Central Standard Time,
> cgalley@qcbc.org writes:
>
> They make solid state converters. I have one for a remote compass
> system.
> Very small and weighs very little.
>
>
> Good Morning Cy,
>
> How much output, how much weight, how much cost and where can it be
> purchased!
>
> Happy Skies,
>
> Old Bob
> AKA
> Bob Siegfried
> Ancient Aviator
> Stearman N3977A
> Brookeridge Airpark LL22
> Downers Grove, IL 60516
> 630 985-8502
>
>
>
Message 15
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| Subject: | Re: Using a 115 volt 400 hz device in a 12 volt airplane |
--> AeroElectric-List message posted by: BobsV35B@aol.com
In a message dated 3/16/2005 4:03:20 P.M. Central Standard Time,
cgalley@qcbc.org writes:
--> AeroElectric-List message posted by: "cgalley" <cgalley@qcbc.org>
Found the price $374 for the little box I have.
Good Afternoon Cy,
When I noted that the company was Mid Continent Instruments, I expected such
a price.
Back when your unit was purchased, MCI was a good company to deal with.
They have now degenerated into the same mode as Grimes Electric. They stick it
to us as bad as anyone in the industry. We sure need some competition in
that arena.
Very sad to see that happen
Thanks for all the information.
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
Stearman N3977A
Brookeridge Airpark LL22
Downers Grove, IL 60516
630 985-8502
Message 16
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| Subject: | Re: Using a 115 volt 400 hz device in a 12 volt |
airplane
--> AeroElectric-List message posted by: Robert McCallum <robert.mccallum2@sympatico.ca>
Tony;
When discussing heaters, the frequency of the power source has no
effect on the power (amount of heat produced) Directly powering your 115
Volt 400Hz heater from your household power will produce very close to
the designed quantity of heat because you are applying the design
voltage. The heat produced by any specific heater varies from the
designed wattage by the square of the applied voltage. In simple terms
if you halve the applied voltage you will get 1/4 of the design wattage.
If you double the applied voltage you will produce 4 times the design
wattage. (and burn out the heater) In your case trying to run a 115 volt
heater on 12 volts is applying approximately 1/10 the design voltage and
you will get 1/100th of the design wattage. In other words almost
nothing, certainly not enough to accomplish anything. Adding a resistor
as you suggest only reduces the voltage (current) even more, further
reducing the already negligible heat you are producing. The most
convenient way to do what you are asking is to buy an inverter for
producing 120 volt AC power from a 12 volt battery and using that to
power your heater. Make sure that the wattage of your inverter is at
least as great or greater than the heater wattage. Bear in mind , as
someone else pointed, out that some inverters may introduce significant
RF noise in your radios or create annoying noise in you intercom. A 12
volt heater is much easier. Hope this sheds some light.
Bob McC
Tony Johnson wrote:
>--> AeroElectric-List message posted by: "Tony Johnson" <tonyjohnson@cfl.rr.com>
>
>I have a pitot tube that is wired for a 115 volts at 400 hz. I would like
>to use it on my RV8A, which will have a 12 volt system.
>
>
>I applied 110v house current to the tube, using a dimmer switch set at the
>lowest setting. The tube heated up. I was afraid to increase the power to
>it.
>
>
>My plan is to acquire an adjustable resistor, set it for high resistance,
>and apply 12volts through it to the tube, probably with a fuse inline
>between the resistor and tube.
>
>
>I would appreciate any input as to how to arrange to use the tube on my 12
>volt system.
>
>
>Tony Johnson
>
>RV8A Orlando
>
>
Message 17
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| Subject: | Re: White Paper on Crowbar OV Protection |
--> AeroElectric-List message posted by: Mike Nellis <mike@bmnellis.com>
Nice attempt at humor but you "digress" to much.
Do not archive
Mike Nellis
Austin, TX
CMRA #32 Honda RC51
'97 YZF1000
'47 Stinson 108-2; RV6 (Fuselage)
http://bmnellis.com
Eric M. Jones wrote:
>--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
>
>Robert, et al.
>
>Re:
>http://www.aeroelectric.com/articles/Crobar_OV_Protection/Crowbar_White_Paper.pdf
>
>About 5000 years ago the Chinese had remarkable scientific techniques. But
>somewhere along the way they decided that an experiment isolated from the
>rest of the world was simply not valid, because it was believed that
>everything influenced everything else. Ahem....but I digress........maybe.
>
>The White Paper skirts the key issue which is: Why bother using the crowbar
>technique when it has been abandoned by the rest of the entire cosmic
>universe for systems such as this? I have in my hand the data sheets for the
>MC3309X line of Motorola alternator voltage regulator chips (the most recent
>of which--MC33099-- contains adaptive logic!...but I digress). Can you guess
>what Motorola uses to terminate the field winding when bad things happen?
>There are about a hundred bazillion of these in service (and sampling the
>product stream to get one is like drinking from a firehose....but I
>digress). No crowbars here bubela.
>
>Nobody argues that a crowbar works, it just isn't used anymore because
>better methods are available. For those who MUST have a crowbar do it this
>way:
>http://www.periheliondesign.com/downloads/NOOVP.pdf But unless the system
>requirement is to make the whole circuit dead in a wink, nobody does this
>anymore.
>
>Now to the White Paper:
>
>1) Cover page is okay except "Over Voltage" should be hyphenated.
>"...Comprised of..." is not English.
>2) What is this drawing? Nobody has an electrical system as shown. The
>Klixon 7274 is the way-fastest part in the series. What is the big diode?
>Why not use the AE Crowbar here instead of whatever stand-in we see? [Insert
>eight-dozen other quibbles here.] If RAC has a spare TDS210 in the closet
>I'd jeeze I'd love to have one. But I digress.....
>3) Okay...short attention span. The rest of the report massages the figures
>a bit but arrives at the conclusion that maybe 263A or so blasts through the
>little 5A Klixon 7274 like a photon torpedo.
>
>Discussion: The Klixon 7274 is not rated for 14.5 V trips of this magnitude.
>While it is rated as "Unlimited Amps at 28V", can we therefore assume that
>this makes 14.5V a piece of cake? Hardly; from 8-16 volts is a kind of
>neverland for electrical contacts---to high for gold and too low for
>silver--the voltages/trip characteristics do not scale. The TI/Klixon graphs
>show the maximum breaking capacity at 28V is 1000% (10X) rated and 0.10 to
>0.40 S. NOT 263/5= 5260% and 15 mS. Assuming we do this anyway--how many
>shots is the breaker now good for? 3? 10? 1000? Who knows?
>
>Discussion: The alternator shown....oops, who stole the darned alternator?
>The alternator does something very bad when crowbarred. It puffs up its
>little cheeks and chest preparing to spew out more electrons, but the next
>second, loadless, it is disappointed and does the Technicolor yawn off the
>back porch. This is my explanation for Load Dump which is better than
>Paul's, but I digress....The alternators contribution to the OVP episode is
>not strictly a DC matter.
>
>Anyway, I suggest that the test setup in not a good representation of what
>is happening in the system.
>
>Finally....whew....we get back to the main question---Why bother hammering
>the electrical system with a crowbar when you don't have to? Let's have some
>common sense.
>
>With great respect...and sorry about the humor...it's those pills the doctor
>makes me take.
>Eric M. Jones
>www.PerihelionDesign.com
>113 Brentwood Drive
>Southbridge MA 01550-2705
>Phone (508) 764-2072
>Email: emjones@charter.net
>
>"The beginning of the end is marked by replacement of experience and common
>sense with policy and procedures."
> -- R. L. Nuckolls III
>
>
>
>
Message 18
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| Subject: | Re: White Paper on Crowbar OV Protection |
--> AeroElectric-List message posted by: "George Braly" <gwbraly@gami.com>
The Motorola part is a nice automotive part.
But it won't work at 28 volts.
And it leaves the system vulnerable to a couple of single point failure modes that
are unacceptable for aviation purposes, in my judgment.
And the very high rate di/dt of the mosfet that it uses for the PWM of the field
generates some ferociously noisy harmonics in the alternator B+ circuit.
Regards, George
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Eric M. Jones
Subject: AeroElectric-List: Re: White Paper on Crowbar OV Protection
--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
Robert, et al.
Re:
http://www.aeroelectric.com/articles/Crobar_OV_Protection/Crowbar_White_Paper.pdf
About 5000 years ago the Chinese had remarkable scientific techniques. But
somewhere along the way they decided that an experiment isolated from the
rest of the world was simply not valid, because it was believed that
everything influenced everything else. Ahem....but I digress........maybe.
The White Paper skirts the key issue which is: Why bother using the crowbar
technique when it has been abandoned by the rest of the entire cosmic
universe for systems such as this? I have in my hand the data sheets for the
MC3309X line of Motorola alternator voltage regulator chips (the most recent
of which--MC33099-- contains adaptive logic!...but I digress). Can you guess
what Motorola uses to terminate the field winding when bad things happen?
There are about a hundred bazillion of these in service (and sampling the
product stream to get one is like drinking from a firehose....but I
digress). No crowbars here bubela.
Nobody argues that a crowbar works, it just isn't used anymore because
better methods are available. For those who MUST have a crowbar do it this
way:
http://www.periheliondesign.com/downloads/NOOVP.pdf But unless the system
requirement is to make the whole circuit dead in a wink, nobody does this
anymore.
Now to the White Paper:
1) Cover page is okay except "Over Voltage" should be hyphenated.
"...Comprised of..." is not English.
2) What is this drawing? Nobody has an electrical system as shown. The
Klixon 7274 is the way-fastest part in the series. What is the big diode?
Why not use the AE Crowbar here instead of whatever stand-in we see? [Insert
eight-dozen other quibbles here.] If RAC has a spare TDS210 in the closet
I'd jeeze I'd love to have one. But I digress.....
3) Okay...short attention span. The rest of the report massages the figures
a bit but arrives at the conclusion that maybe 263A or so blasts through the
little 5A Klixon 7274 like a photon torpedo.
Discussion: The Klixon 7274 is not rated for 14.5 V trips of this magnitude.
While it is rated as "Unlimited Amps at 28V", can we therefore assume that
this makes 14.5V a piece of cake? Hardly; from 8-16 volts is a kind of
neverland for electrical contacts---to high for gold and too low for
silver--the voltages/trip characteristics do not scale. The TI/Klixon graphs
show the maximum breaking capacity at 28V is 1000% (10X) rated and 0.10 to
0.40 S. NOT 263/5= 5260% and 15 mS. Assuming we do this anyway--how many
shots is the breaker now good for? 3? 10? 1000? Who knows?
Discussion: The alternator shown....oops, who stole the darned alternator?
The alternator does something very bad when crowbarred. It puffs up its
little cheeks and chest preparing to spew out more electrons, but the next
second, loadless, it is disappointed and does the Technicolor yawn off the
back porch. This is my explanation for Load Dump which is better than
Paul's, but I digress....The alternators contribution to the OVP episode is
not strictly a DC matter.
Anyway, I suggest that the test setup in not a good representation of what
is happening in the system.
Finally....whew....we get back to the main question---Why bother hammering
the electrical system with a crowbar when you don't have to? Let's have some
common sense.
With great respect...and sorry about the humor...it's those pills the doctor
makes me take.
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones@charter.net
"The beginning of the end is marked by replacement of experience and common
sense with policy and procedures."
-- R. L. Nuckolls III
---
---
Message 19
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| Subject: | Re: White Paper on Crowbar OV Protection |
--> AeroElectric-List message posted by: Robert McCallum <robert.mccallum2@sympatico.ca>
Mike Nellis wrote:
>--> AeroElectric-List message posted by: Mike Nellis <mike@bmnellis.com>
>
>Nice attempt at humor but you "digress" to much.
>
>
Isn't that "too" much??????- - - - digression that is.
definitely DO NOT ARCHIVE
Bob McC
>Do not archive
>
>Mike Nellis
>
>
Message 20
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| Subject: | Re: White Paper on Crowbar OV |
Protection
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <b.nuckolls@cox.net>
Protection
At 04:58 PM 3/16/2005 -0500, you wrote:
>--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
>
>Robert, et al.
>
>Re:
>http://www.aeroelectric.com/articles/Crobar_OV_Protection/Crowbar_White_Paper.pdf
>
>About 5000 years ago the Chinese had remarkable scientific techniques. But
>somewhere along the way they decided that an experiment isolated from the
>rest of the world was simply not valid, because it was believed that
>everything influenced everything else. Ahem....but I digress........maybe.
If the experiment is too complex, then the results are not repeatable
due to outside influences and does not illuminate a simple-idea. The
standard for the Coulomb (ampere-second) is defined in a manner
that anyone with the appropriate equipment can repeat the experiment
and obtain the same results. My wife is an expert at complex experiments
but it takes a really agile program to do statistical analysis on
data and to predict cause and effect with reasonable certainty. I'll
suggest we avoid statistics for this study and concentrate on the
repeatable physics.
>The White Paper skirts the key issue which is: Why bother using the crowbar
>technique when it has been abandoned by the rest of the entire cosmic
>universe for systems such as this?
I haven't skirted anything. The white paper makes no recommendations
nor does it reflect anyone's opinions.
> I have in my hand the data sheets for the
>MC3309X line of Motorola alternator voltage regulator chips (the most recent
>of which--MC33099-- contains adaptive logic!...but I digress). Can you guess
>what Motorola uses to terminate the field winding when bad things happen?
>There are about a hundred bazillion of these in service (and sampling the
>product stream to get one is like drinking from a firehose....but I
>digress). No crowbars here bubela.
To my knowledge crowbar ov protection has never been used in
the automotive world. Further, as far as I know, I was the first
to introduce it to aviation when it was the ONLY system that would
qualify on the turbine Bonanza out of a field of several dozen
commonly available OV relays of the time.
>Nobody argues that a crowbar works, it just isn't used anymore because
>better methods are available. For those who MUST have a crowbar do it this
>way:
>http://www.periheliondesign.com/downloads/NOOVP.pdf But unless the system
>requirement is to make the whole circuit dead in a wink, nobody does this
>anymore.
Haven't even addressed requirements yet. That's getting way ahead
of the study at hand.
>Now to the White Paper:
>
>1) Cover page is okay except "Over Voltage" should be hyphenated.
>"...Comprised of..." is not English.
>2) What is this drawing? Nobody has an electrical system as shown. The
>Klixon 7274 is the way-fastest part in the series.
The experiment is not intended to duplicate anyone's electrical
system. Is it your suggestion that the experiment be repeated with
another circuit breaker? 7274 series is all I have in my junk
box. You pick a number, I'll go find one.
> What is the big diode?
MCR69 SCR
>Why not use the AE Crowbar here instead of whatever stand-in we see? [Insert
>eight-dozen other quibbles here.]
The purpose of this experiment was to deduce exactly what the
measured data shows. Peak currents, delay times and influences on
bus voltage when subjected to those current. I mentioned
at the end of the paper that we'll go explore the dynamic characteristics
of the design under study. That's a separate experiment/analysis
and will probably use the full-up OVM-14
> If RAC has a spare TDS210 in the closet
>I'd jeeze I'd love to have one. But I digress.....
RAC doesn't own own as far as I know. It's part of my personally
owned professional tools.
>3) Okay...short attention span. The rest of the report massages the figures
>a bit but arrives at the conclusion that maybe 263A or so blasts through the
>little 5A Klixon 7274 like a photon torpedo.
Yes . . . so? If the 7274 were sitting on someone's aircraft breaker
panel and the downstream wire gets faulted, is there any guarantee
that the fault current won't be 263 or more or less? This isn't
germane to the discussion.
You've missed the point of the paper. The "stand in" is indeed an
MCR69 device, exactly as used in several hundreds of OVM-14 modules
produced over the past 10 years or so.
>Discussion: The Klixon 7274 is not rated for 14.5 V trips of this magnitude.
Perhaps you're privy to some limitations on the 7274 that I am not.
It's indeed rated at 28v which accounts for 95% of its application.
Where do we read that stresses for 14v operation depart markedly
from those cited for 28v. I can call the guys at Eaton/Cuttler-Hammer
tomorrow if we're needing any documentation. Can you enlighten me?
>While it is rated as "Unlimited Amps at 28V", can we therefore assume that
>this makes 14.5V a piece of cake? Hardly; from 8-16 volts is a kind of
>neverland for electrical contacts---to high for gold and too low for
>silver--the voltages/trip characteristics do not scale.
I wouldn't suggest that they do. Assuming that a builder does
use a 7274 Klixon in his system. What is the risk? Is the breaker
at risk of failing to open? Failing to re-close after an OV event?
Reduction in service life from the published 2500 cycles at
30VDC resistive? If it were reduced to perhaps 100 cycles, should
I care? In any case, the experiment wasn't about breaker selection.
Pick another breaker and I'll go find one.
> The TI/Klixon graphs
>show the maximum breaking capacity at 28V is 1000% (10X) rated and 0.10 to
>0.40 S. NOT 263/5= 5260% and 15 mS. Assuming we do this anyway--how many
>shots is the breaker now good for? 3? 10? 1000? Who knows?
I assume nothing about the 7274. It's a breaker that came from
my junkbox to investigate the values measured and cited. If you
have other measurements you'd like to see, please state them
and the suggested test setup and I'll go see what I get.
Again, you're missing the point of the experiment. I belive I've
read numbers cited that crowbar currents as high as 700 amps
have been measured. My question is: what was the setup so that
I might go to my workbench and measure those currents myself?
I've read numbers citing time delays far longer than anything
I've seen in about 15 years of producing this system. I'm not
arguing with those numbers, only trying to deduce how they were
acquired. I've often suggested that the repeatable experiment
is the Holy Grail of quantification and understanding. To date,
I've seen lots of numbers which mystify me. Soooo . . . an hour
or so at the workbench produced the data cited to date. More
is yet to come.
>Discussion: The alternator shown....oops, who stole the darned alternator?
>The alternator does something very bad when crowbarred. It puffs up its
>little cheeks and chest preparing to spew out more electrons, but the next
>second, loadless, it is disappointed and does the Technicolor yawn off the
>back porch. This is my explanation for Load Dump which is better than
>Paul's, but I digress....The alternators contribution to the OVP episode is
>not strictly a DC matter.
I believe I understand but I'm not convinced that my understanding
matches yours. We spoke of some testing to be done and data
to be shared but to date, pronouncements are made
on suitability or lack of suitability-to-task with little or
no foundation in repeatable experiments. I did a lot
of this same work 20 years ago for Beech and again 5 years later
for B&C. I'm repeating it again with the intent of laying out
exactly what I've done, the measurements I've acquired and
my interpretation of their significance. I've acquired an alternator
test stand and hope to pick it up next week sometime when my
son lets me have my truck back.
>Anyway, I suggest that the test setup in not a good representation of what
>is happening in the system.
The test setup IS a representation of exactly what it shows and no more.
It describes a study and analysis of source impedances and current
limitations based on a choice of materials that would normally be
EXPECTED to produce the highest crowbar currents. Admittedly this
investigation
is a small part of the whole. But I find it useful to investigate one
feature at a time. Recall my penchant for boiling system operations
down to their rudimentary components . . . simple ideas that stand alone
and are easily understood and INVARIABLE. Then we'll start stacking
them together to see if the system performance is meeting objectives.
>Finally....whew....we get back to the main question---Why bother hammering
>the electrical system with a crowbar when you don't have to? Let's have some
>common sense.
Define "hammer" . . . Please use quantified terminology. You seem to
object to deliberate development of a current pulse designed to open
a breaker under circumstances it is DESIGNED to handle. The experiment
thus far is intended to DEMONSTRATE that currents developed the typical
system are modest compared to values cited without benefit of a supporting
experiment. Further, they are deduced to not place any other part of the
system at risk in that bus voltage excursions are no worse than for
energizing a landing gear pump. It's was intended to INVESTIGATE the
elusive 700A pulse . . . or even a 300A pulse for that matter. The only
time I saw a crowbar event of 300A was on Bill's 24v test stand with
very atypical wiring lengths. The bench test setup I wrote about
demonstrated a crowbar event of less than 200 amps.
>With great respect...and sorry about the humor...it's those pills the doctor
>makes me take.
Understand. Had to change my blood pressure medicine several times
before I found one I can live with and still does the job. My invitation
is to join in analysis of the data presented thus far. I'll be pleased to
explore the features cited in a manner that can be repeated by anyone else
at any time. This isn't a contest or an attempt to persuade anyone of
anything. Let's go get the data and understand the physics that drives it.
If you have suggestions to make for further testing in Phase I, I'd be
pleased to respond. After all the numbers are in, only then does anyone
have all the information needed to participate in their own decision making
process.
Bob . . .
Message 21
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| Subject: | Re: Using a 115 volt 400 hz device in a 12 |
volt airplane
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <b.nuckolls@cox.net>
volt airplane
AC power systems are the wave of the future for most airplanes above
15,000 pounds. Our Horizon uses a wild frequency AC system and I'm
specifying some AC generation equipment onto a much smaller airplane.
Our smaller Hawkers have big inverters.
Now, if one wants to talk about WIRE WEIGHT reduction, high voltage
AC is the way to get it. 208V 3-phase provides 115V from any leg
to ground for small appliances. But when run through a rectifier,
the 208 3-phase produces 270 VDC to run brushless DC motors. An
air conditioner system that draws 200A at 28v draws only 20A
at 270 VDC. This current is easily carried on a twisted trio of
16 AWG wires where it took a pair of 2AWG wires before. Further,
the ship's airframe is NOT used for grounding on the high power
3-phase systems so that no ground loop noises are injected to
other systems.
Inverters for developing 400Hz AC come in ALL sizes ranging from
25 watt devices weighing perhaps 8 ounces and used to drive
an instrument up to 1500 watt hogs that weigh in around 40
pounds and have BIG cooling fans on them. The very best way
to generate lots of AC is from an engine driven alternator.
400 Hz AC power has been around since before WWII on larger
aircraft for a variety of task but until 1950's was not used
for whole-aircraft power. I think our Horizon has two
transformer/rectifiers that develop about 50A each to handle
ALL DC requirements. Everything else runs from the AC power.
The Beechjet has two 400A generators to run it's DC only
systems.
Bob . . .
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