Today's Message Index:
----------------------
1. 05:21 AM - Re: Another 60A alternator, internally regulated voltage regulator failure (luckymacy@comcast.net (lucky))
2. 06:54 AM - Re: Need low cost schematic program (Jan de Jong)
3. 08:32 AM - larger wire fuselinks (Bill Boyd)
4. 10:24 AM - Re: larger wire fuselinks (Robert L. Nuckolls, III)
5. 10:24 AM - Re: larger wire fuselinks (Bill Boyd)
6. 10:30 AM - Re: Need low cost schematic program (Robert L. Nuckolls, III)
7. 10:57 AM - Re: Need low cost schematic program (Roger Bentlage)
8. 03:57 PM - Annunciator schematic (Nathan Ulrich)
9. 04:53 PM - Re: Need low cost schematic program (Richard Tasker)
10. 06:51 PM - Re: Need low cost schematic program (Robert L. Nuckolls, III)
11. 06:51 PM - ExpressPCB was : Need low cost schematic program (Ed Anderson)
12. 06:59 PM - Re: Fat Capacitor Question (Robert L. Nuckolls, III)
13. 07:07 PM - Serial input transponders? (Dr. Andrew Elliott)
14. 07:10 PM - Re: Need low cost schematic program (Ed Anderson)
15. 08:13 PM - Re: Serial input transponders? (William Gill)
Message 1
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Subject: | Re: Another 60A alternator, internally regulated voltage |
regulator failure
14824
What's the URL that you can get maintenance/recall history on parts?
thx,
lucky
-------------- Original message --------------
From: "Bill Boyd" <sportav8r@gmail.com>
>
> Lucky, mind sharing the part # on the alternator? It might be the
> same as the Geo Metro 55A machine I just installed (I'd have to pull
> the cowl to look) but I'd like to know if it had a significant OV
> failure mode history.
>
> Thanks,
>
> -Bill B
>
> On 1/8/07, lucky wrote:
> >
> > My update. I bought an alternator from Autozone that matched the
> > suzuki/chevrolet automobile replacement alternator often quoted to be the
> > same as Van's 60 amp internally regulated alternator even though the part
> > number was just slightly different. I could not tell a difference from the
> > outside though their computer said 55 amp and not 60 amp. It has a
> > Nippondenso internal fan and a hotline of 800 228 9672.
> >
> > In the install manual, it has a CAUTION: A defective or discharged battery
> > can damage your new alternator.
> >
> > But the reason my alternator may have failed is that there was one of the
> > feet on the alternator was cracked clean through. Though it was still
> > rigidly mounted that had to set up some fun vibration within the alternator
> > itself. Don't know if that actually was a cause for the battery to fail as
> > opposed to the opposite hypothesis I was banting about.
> >
> > Fun stuff. I still have the magic alternator killing odyssey pc680 battery
> > I removed if anyone has a Van's 60amp alternator they want to test for
> > kill..... ;-)
> >
> > Next task is to replace the high intensify landing/taxi light bulbs that
> > burned out when turned on with 18 volts on the bus....
> >
> > lucky
> >
> > -------------- Original message --------------
> > From: Ken
> >
> > >
> > > For years I was skeptical too that a weak battery would hasten
> > > alternator death. However eventually I developed a few thoughts on why
> > > there may be some truth to this in automobiles.
> > >
> > > 1. Higher longer charging does tend to make the alternator run hotter
> > > and some internal VR alternators are not well cooled. Any vehicle that
> > > is started with jumper cables is about to ask for a serious effort from
> > > its charging system.
> > >
> > > 2. Installing a new but partly charged battery may stress the alternator
> > > even higher than ever as it charges the battery at max current for an
> > > extended period. An old alternator just may not be up to the ef fort.
> > > Maybe the brushes are worn or maybe the solid state devices get hotter
> > > than they have for awhile. Certainly the cooling of old greasy/dirty
> > > components is not as good as on a clean new unit. I'm not sure that a
> > > test stand is going to successfully imitate the service environment that
> > > I'm thinking of. This might explain death shortly after the new battery
> > > is installed though.
> > >
> > > 3. Weak "maintenance free" batteries are sometimes low on electrolyte. I
> > > think that further reduces their capacity to absorb any excess voltage
> > > or current and might lead to more voltage excursions. Most people never
> > > pop the caps off automobile batteries any more as it is often not
> > > obvious how to do it, or that it can be done. It seems that my little
> > > (8AH) AGM batteries will accept very little current initially when fully
> > > discharged.
> > >
> > > 4. As a WAG another contrib ution might be abnormal operation while
> > > fooling around with a weak battery. If I leave the ignition/key on with
> > > my ND IR alternator on my aircraft without starting the engine, the
> > > alternator does draw several amps of field current and it will heat up
> > > quite noticeably with no cooling airflow.
> > >
> > > Anyway my personal rule now is to change out any suspicious battery with
> > > a new FULLY charged unit and I can sometimes send the vehicle to the
> > > wreckers with the original alternator. I do run weak batteries in my
> > > tractor but that has an external homemade VR that hangs out in the
> > > breeze (like the alternator) and everything runs very very cool ;)
> > >
> > > Ken
> > >
> > > >> SNIP>
> > > >> I had heard that a "weak" battery can damage the alternator/regulator
> > > >> so this seamed to have validated that statement. For sure though,
> > > >> from my observations , the battery appeared to go bad first then 2
> > > >> hours later after a new battery was installed the regulator seems to
> > > >> have failed.
> > > >
> > > >
> > > > I'm skeptical of such claims. Consider how many batteries
> > > > you've replaced in cars without having to replace the alternator
> > > > too.
> > > >
> > > > I've "killed" a few alternators in various test situations
> > > > but all failures involved either loss of cooling or mechanical
> > > > issues such as bearing or shear-shaft failures.
> > > >
> > > > The way to "test" a weak-battery-kills-alternators hypothesis is
> > > > to separate the two components and then craft a test plan designed
> > > > to kill an alternator. In other words, if I had a brand new
> > > > alternator and a charter to damage it in some way on the test
> > > > stand, what kinds of abuses might I heap upon the unsuspecting
> > > ; > device to bring about its untimely demise?
> > > >
> > > > Once such a test plan is devised, then deduce how battery
> > > > behavior mimics any of the abuses you've crafted for the
> > > > purpose of killing an alternator.
> > > >
> > > > I'd be interested in anyone's ideas as to how you might go
> > > > about it. Alternators are inherently self current limiting.
> > > > Given sufficient cooling air, you cannot "overload" one to
> > > > destruction. Alternator diodes are robust and will withstand
> > > > reverse voltage transients many times greater than system voltage.
> > > > It's the regulators that are most vulnerable to a load-dump
> > > > event and that's been demonstrated by several builders using
> > > > Van's (and perhaps other) alternators combined with b-lead
> > > > contactor controls.
> > > >
> > > > I'm not suggesting that battery condition might not be a bit-player
> > & gt; > in a scenario that's hard on alternators. For example:
> > > > I can see how the "weak battery" thing might have morphed into
> > > > a cause/effect for alternator failure where someone knows that
> > > > having a battery be disconnected from the alternator at the same
> > > > time all loads are removed causes a potentially hazardous
> > > > over-shoot. One might deduce that a "weak" battery has
> > > > lost its ability to mitigate a load-dump events thereby
> > > > placing the alternator at-risk.
> > > >
> > > > If this hypothesis were in play for your situation, the alternator
> > > > seems most likely to have failed while the "weak" battery was
> > > > in place. Certainly having a "strong" new battery in place totally
> > > > eliminates the risk for hazardous transients during ordinary
> > > > system load reductions.
> > > >
> > > > This could be hypothetically thrashed for d ays bu
> >
> > http://www.matronics.com/Navigator?AeroElectric-List
> >
> >
> >
>
>
>
>
<html><body>
<DIV>14824</DIV>
<DIV> </DIV>
<DIV>What's the URL that you can get maintenance/recall history on parts?</DIV>
<DIV> </DIV>
<DIV>thx,</DIV>
<DIV>lucky</DIV>
<DIV> </DIV>
<BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px
solid">-------------- Original message -------------- <BR>From: "Bill Boyd"
<sportav8r@gmail.com> <BR><BR>> --> AeroElectric-List message posted
by: "Bill Boyd" <SPORTAV8R@GMAIL.COM><BR>> <BR>> Lucky, mind sharing
the part # on the alternator? It might be the <BR>> same as the Geo Metro 55A
machine I just installed (I'd have to pull <BR>> the cowl to look) but I'd
like to know if it had a significant OV <BR>> failure mode history. <BR>>
<BR>> Thanks, <BR>> <BR>> -Bill B <BR>> <BR>> On 1/8/07, lucky
<LUCKYMACY@COMCAST.NET>wrote: <BR>> > <BR>> > My update. I bought
an alternator from Autozone that matched the <BR>> > suzuki/chevrolet
automobile replacement alternator often quoted to be the <BR>> > same
as Van's 60 amp internally regulated alternator even though the part <BR>>
> number was just slightly different. I could not
tell
a difference from the <BR>> > outside though their computer said 55 amp and
not 60 amp. It has a <BR>> > Nippondenso internal fan and a hotline of
800 228 9672. <BR>> > <BR>> > In the install manual, it has a CAUTION:
A defective or discharged battery <BR>> > can damage your new alternator.
<BR>> > <BR>> > But the reason my alternator may have failed
is that there was one of the <BR>> > feet on the alternator was cracked
clean through. Though it was still <BR>> > rigidly mounted that had
to set up some fun vibration within the alternator <BR>> > itself. Don't
know if that actually was a cause for the battery to fail as <BR>> > opposed
to the opposite hypothesis I was banting about. <BR>> > <BR>> >
Fun stuff. I still have the magic alternator killing odyssey pc680 battery
<BR>> > I removed if anyone has a Van's 60amp alternator they want to test
for <BR>> > kill..... ;-) <BR>> > <BR
>>
> Next task is to replace the high intensify landing/taxi light bulbs that <BR>>
> burned out when turned on with 18 volts on the bus.... <BR>> >
<BR>> > lucky <BR>> > <BR>> > -------------- Original message
-------------- <BR>> > From: Ken <KLEHMAN@ALBEDO.NET><BR>> >
<BR>> > > --> AeroElectric-List message posted by: Ken <BR>> >
> <BR>> > > For years I was skeptical too that a weak battery
would hasten <BR>> > > alternator death. However eventually I developed
a few thoughts on why <BR>> > > there may be some truth to this in
automobiles. <BR>> > > <BR>> > > 1. Higher longer charging
does tend to make the alternator run hotter <BR>> > > and some internal
VR alternators are not well cooled. Any vehicle that <BR>> > > is
started with jumper cables is about to ask for a serious effort from <BR>>
> > its charging system. <BR>> > > <BR
>>
> > 2. Installing a new but partly charged battery may stress the alternator
<BR>> > > even higher than ever as it charges the battery at max
current for an <BR>> > > extended period. An old alternator just may
not be up to the ef fort. <BR>> > > Maybe the brushes are worn or maybe
the solid state devices get hotter <BR>> > > than they have for awhile.
Certainly the cooling of old greasy/dirty <BR>> > > components
is not as good as on a clean new unit. I'm not sure that a <BR>> > >
test stand is going to successfully imitate the service environment that <BR>>
> > I'm thinking of. This might explain death shortly after the new
battery <BR>> > > is installed though. <BR>> > > <BR>> >
> 3. Weak "maintenance free" batteries are sometimes low on electrolyte.
I <BR>> > > think that further reduces their capacity to absorb any
excess voltage <BR>> > > or current and migh
t lead
to more voltage excursions. Most people never <BR>> > > pop the caps
off automobile batteries any more as it is often not <BR>> > > obvious
how to do it, or that it can be done. It seems that my little <BR>> >
> (8AH) AGM batteries will accept very little current initially when fully
<BR>> > > discharged. <BR>> > > <BR>> > > 4. As a WAG
another contrib ution might be abnormal operation while <BR>> > >
fooling around with a weak battery. If I leave the ignition/key on with <BR>>
> > my ND IR alternator on my aircraft without starting the engine, the
<BR>> > > alternator does draw several amps of field current and it
will heat up <BR>> > > quite noticeably with no cooling airflow. <BR>>
> > <BR>> > > Anyway my personal rule now is to change out
any suspicious battery with <BR>> > > a new FULLY charged unit and
I can sometimes send the vehicle to the <BR>> >
; >
wreckers with the original alternator. I do run weak batteries in my <BR>>
> > tractor but that has an external homemade VR that hangs out in the <BR>>
> > breeze (like the alternator) and everything runs very very cool
;) <BR>> > > <BR>> > > Ken <BR>> > > <BR>> >
> >> SNIP> <BR>> > > >> I had heard that a "weak"
battery can damage the alternator/regulator <BR>> > > >> so
this seamed to have validated that statement. For sure though, <BR>> > >
>> from my observations , the battery appeared to go bad first then
2 <BR>> > > >> hours later after a new battery was installed the
regulator seems to <BR>> > > >> have failed. <BR>> > >
> <BR>> > > > <BR>> > > > I'm skeptical of such
claims. Consider how many batteries <BR>> > > > you've replaced in
cars without having to replace the alternator <BR>&g
t; >
; > > too. <BR>> > > > <BR>> > > > I've "killed"
a few alternators in various test situations <BR>> > > > but all failures
involved either loss of cooling or mechanical <BR>> > > >
issues such as bearing or shear-shaft failures. <BR>> > > > <BR>>
> > > The way to "test" a weak-battery-kills-alternators hypothesis
is <BR>> > > > to separate the two components and then craft a test
plan designed <BR>> > > > to kill an alternator. In other words,
if I had a brand new <BR>> > > > alternator and a charter to damage
it in some way on the test <BR>> > > > stand, what kinds of abuses
might I heap upon the unsuspecting <BR>> > > ; > device to bring
about its untimely demise? <BR>> > > > <BR>> > > >
Once such a test plan is devised, then deduce how battery <BR>> > >
> behavior mimics any of the abuses you've crafte
d for
the <BR>> > > > purpose of killing an alternator. <BR>> > >
> <BR>> > > > I'd be interested in anyone's ideas as to how you
might go <BR>> > > > about it. Alternators are inherently self
current limiting. <BR>> > > > Given sufficient cooling air, you cannot
"overload" one to <BR>> > > > destruction. Alternator diodes
are robust and will withstand <BR>> > > > reverse voltage transients
many times greater than system voltage. <BR>> > > > It's the regulators
that are most vulnerable to a load-dump <BR>> > > > event
and that's been demonstrated by several builders using <BR>> > > >
Van's (and perhaps other) alternators combined with b-lead <BR>> > >
> contactor controls. <BR>> > > > <BR>> > > > I'm
not suggesting that battery condition might not be a bit-player <BR>> >
& gt; > in a scenario that's hard on alternat
ors. F
or example: <BR>> > > > I can see how the "weak battery" thing might
have morphed into <BR>> > > > a cause/effect for alternator failure
where someone knows that <BR>> > > > having a battery be disconnected
from the alternator at the same <BR>> > > > time all loads
are removed causes a potentially hazardous <BR>> > > > over-shoot.
One might deduce that a "weak" battery has <BR>> > > > lost its
ability to mitigate a load-dump events thereby <BR>> > > > placing
the alternator at-risk. <BR>> > > > <BR>> > > > If this
hypothesis were in play for your situation, the alternator <BR>> > >
> seems most likely to have failed while the "weak" battery was <BR>>
> > > in place. Certainly having a "strong" new battery in place totally
<BR>> > > > eliminates the risk for hazardous transients during
ordinary <BR>> > > > system load reduc
tions.
<BR>&g
t; <BR>> </BLOCKQUOTE>
<pre><b><font size=2 color="#000000" face="courier new,courier">
</b></font></pre></body></html>
Message 2
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Subject: | Re: Need low cost schematic program |
It seems that ExpressPCB output format is proprietary - no Gerber files
- and not supported by other prototype PCB makers.
A possible consideration.
Jan de Jong
Message 3
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Subject: | larger wire fuselinks |
Bob- your site says to contact you for fabrication of larger
fuselinks than 20 or 22 AWG.
I'm going to need an 8 AWG fuselink in my 4 AWG starter/alternator B+
wire. Pointers, please?
-Bill B
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Subject: | Re: larger wire fuselinks |
At 11:31 AM 1/15/2007 -0500, you wrote:
>
>Bob- your site says to contact you for fabrication of larger
>fuselinks than 20 or 22 AWG.
>
>I'm going to need an 8 AWG fuselink in my 4 AWG starter/alternator B+
>wire. Pointers, please?
Use an ANL or MAX-inline fuse holder. Fusible links should
not be applied to uses other than those illustrated and
sized in the Z-figures.
Bob . . .
---------------------------------------------------------
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
---------------------------------------------------------
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Subject: | Re: larger wire fuselinks |
I'm sorry, that should read, the 8AWG run from the alternator to the
PM starter solenoid lug needs a 12 AWG fuselink; can you advise how
best to construct one?
The run from the battery to the starter is obviously protected by the
battery contactor; my fault for not having the schematic open in front
of me as I wrote the querry.
-Bill
On 1/15/07, Bill Boyd <sportav8r@gmail.com> wrote:
> Bob- your site says to contact you for fabrication of larger
> fuselinks than 20 or 22 AWG.
>
> I'm going to need an 8 AWG fuselink in my 4 AWG starter/alternator B+
> wire. Pointers, please?
>
> -Bill B
>
Message 6
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Subject: | Re: Need low cost schematic program |
At 03:53 PM 1/15/2007 +0100, you wrote:
>
>It seems that ExpressPCB output format is proprietary - no Gerber files -
>and not supported by other prototype PCB makers.
>A possible consideration.
>Jan de Jong
Correct . . . but after years of doing business with
them (and considering/using a variety of options) their
pricing and service for the low volume OBAM aircraft
market has over-ridden these concerns.
It's exceedingly unlikely that anyone on the List is
going to regret having used ExpressPCB because of a
future wish to have a few thousand boards fabricated.
Bob . . .
---------------------------------------------------------
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
---------------------------------------------------------
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Subject: | Re: Need low cost schematic program |
A number of programs are available for free download at:
http://www.freecad.com/cgi-bin/dcd/html/CAD_Programs___General_Purpose/
I use a purchased copy of EasyCAD for basic 2-axis stuff (wiring diagrams) because
of its simplicity.
I use A9CAD, downloadable free from the above site, for more complex applications.
It's comfortable with AutoCAD output.
Attached is a copy of my dual batt, dual alt, all electric RV-7. Criticisms are
welcome.
Roger
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=87817#87817
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Subject: | Annunciator schematic |
Al:
Unfortunately, I don't have a schematic, I kind of winged it a little bit
since the circuit is so easy. I'm only a *mechanical* engineer, after all
;).
I'd be glad to share the ExpressPCB layout file with anyone who is
interested. Just send me your email address.
Nathan
--- Begin forwarded message ---
Hi Nathan:
I saved your e-mail for a time when I wasn't so busy, thus the delay in
responding.
I would like a little more info on your annunciator. As I am somewhat
electronically challenged, your circuitry would be of particular
interest. Beautiful machining, by the way.
Thanks,
Al Etherington
Message 9
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Subject: | Re: Need low cost schematic program |
True, but why compromise on a proprietary format when you can get Eagle
for free and do any layouts up to 4" x 6" with schematic capture and
Gerber outputs usable by any PCB house. http://www.cadsoft.de/
Dick Tasker
Robert L. Nuckolls, III wrote:
> <nuckollsr@cox.net>
>
> At 03:53 PM 1/15/2007 +0100, you wrote:
>
>> <jan.de.jong@xs4all.nl>
>>
>> It seems that ExpressPCB output format is proprietary - no Gerber
>> files - and not supported by other prototype PCB makers.
>> A possible consideration.
>> Jan de Jong
>
>
> Correct . . . but after years of doing business with
> them (and considering/using a variety of options) their
> pricing and service for the low volume OBAM aircraft
> market has over-ridden these concerns.
>
> It's exceedingly unlikely that anyone on the List is
> going to regret having used ExpressPCB because of a
> future wish to have a few thousand boards fabricated.
>
>
> Bob . . .
>
>
> ---------------------------------------------------------
> < What is so wonderful about scientific truth...is that >
> < the authority which determines whether there can be >
> < debate or not does not reside in some fraternity of >
> < scientists; nor is it divine. The authority rests >
> < with experiment. >
> < --Lawrence M. Krauss >
> ---------------------------------------------------------
>
>
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Subject: | Re: Need low cost schematic program |
At 07:52 PM 1/15/2007 -0500, you wrote:
><retasker@optonline.net>
>
>True, but why compromise on a proprietary format when you can get Eagle
>for free and do any layouts up to 4" x 6" with schematic capture and
>Gerber outputs usable by any PCB house. http://www.cadsoft.de/
>
>Dick Tasker
. . . is there a fab house that inputs Gerber plots
that will do 5-day turnaround prototypes for $51 + 2nd
day air?
Bob . . .
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Subject: | Need low cost schematic program |
While I have been a satisfied customer of ExpressPCB for a number of years
and think they are indeed a great PCB provider, I have lately found some of
there limitations - well, rather limiting. I have decided to convert my
project design from through-hole to surface Mount (ugh! those components are
almost invisible!).
In order to keep my sanity, I decided that using a stencil to lay on the
bare board for a limited number of units would be an ideal way to go. This
stencil is simply a thin metal (or plastic) sheet with holes very precisely
cut to fit over those component pads you wish to have a solder paste
deposited on. So you put the paste on the stencil and use a squeegee to
pull the paste across all the holes in the stencil thereby depositing the
solder paste only where you are going to put a component.
Then you use a magnifying glass and tweezers to put the tiny components on
their pads and pop them into an oven and voila (if everything goes right)
you have a solder surface mount board.
Now the problem is that ExpressPCB does not offer the stencil service,
furthermore most firms offering the stencil service require a set of Gerber
files (normal CAD output of most PC board software). You can not directly
produce one from the ExpressPCB software. You must pay an additional $60
for a Gerber file from ExpressPCB. This is the file that EAGLE and some of
the other readily available PC board software produces that file as a normal
course. So $60 just seems a bit much when there are package that produce it
free.
A PCB software package that produces such non-proprietary Gerber files also
give you a much greater range of service providers including all the way to
China (very nice prices if you can stand the transportation delay).
So I believe, as Bob pointed out - it all depends on what your needs are.
For one of a kind, or a few, ExpressPCB offers a valued service at a
reasonable price. Up to now, I have used no other. But, some of their
limitations in face of my current needs are causing me to reconsider.
FWF
Ed
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com
http://members.cox.net/rogersda/rotary/configs.htm#N494BW
http://www.dmack.net/mazda/index.html
----- Original Message -----
From: "Richard Tasker" <retasker@optonline.net>
Sent: Monday, January 15, 2007 7:52 PM
Subject: Re: AeroElectric-List: Need low cost schematic program
> <retasker@optonline.net>
>
> True, but why compromise on a proprietary format when you can get Eagle
> for free and do any layouts up to 4" x 6" with schematic capture and
> Gerber outputs usable by any PCB house. http://www.cadsoft.de/
>
> Dick Tasker
>
> Robert L. Nuckolls, III wrote:
>
>> <nuckollsr@cox.net>
>>
>> At 03:53 PM 1/15/2007 +0100, you wrote:
>>
>>> <jan.de.jong@xs4all.nl>
>>>
>>> It seems that ExpressPCB output format is proprietary - no Gerber
>>> files - and not supported by other prototype PCB makers.
>>> A possible consideration.
>>> Jan de Jong
>>
>>
>> Correct . . . but after years of doing business with
>> them (and considering/using a variety of options) their
>> pricing and service for the low volume OBAM aircraft
>> market has over-ridden these concerns.
>>
>> It's exceedingly unlikely that anyone on the List is
>> going to regret having used ExpressPCB because of a
>> future wish to have a few thousand boards fabricated.
>>
>>
>> Bob . . .
>>
>>
>> ---------------------------------------------------------
>> < What is so wonderful about scientific truth...is that >
>> < the authority which determines whether there can be >
>> < debate or not does not reside in some fraternity of >
>> < scientists; nor is it divine. The authority rests >
>> < with experiment. >
>> < --Lawrence M. Krauss >
>> ---------------------------------------------------------
>>
>>
>>
>>
>>
>>
>
>
>
Message 12
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Subject: | Re: Fat Capacitor Question |
At 09:33 PM 1/14/2007 -0500, you wrote:
><mjurotich@hst.nasa.gov>
>
>I am thinking of putting a Fat capacitor between the E bus and
>ground. Idea is
>
>if the E bus switch is open
>and the battery is suppling power through the diode
>and the voltage sags for a short time (300 milliseconds is what I
>remember) when first engaging the starter
>
>the capacitor would keep the voltage above 10 for the voltage sensitive
>stuff that may reset.
>2 questions:
>Would this work?
Sure. In fact it's been done. The quick-n-dirty design
tool takes notice of the fact that a 1F capacitor discharged
at 1A will fall at 1V per second. So, assuming the system you're
protecting draws 3A. Assume further you want to keep the voltage
from falling below 10v with a start from 12v. Assume further that
you want to support the device for 1/2 second.
A/F = V/S
3/F = 2/0.5
3/F = 4
F = 0.75 Farads
That's a FAT capacitor. You can buy 1F caps popular with the
folks who like to install ear-crusher audio systems in their
vehicles. See:
http://tinyurl.com/tvrtx
The capacitor can get small by reducing supported
current, reducing support-time or allowing a greater voltage
drop during inrush transient.
If your system will benefit from some form of transient isolation
system, I think you'll find that a small battery is a much better
energy storage device. The smallest of SVLA batteries can be isolated
from the rest of the system during a few seconds of cranking time.
The installed weight and volume will be smaller but there will be
a preventative maintenance issue for the AUX battery. In this case,
AUX battery capacity is not a big issue ASSUMING that its only
task is to mitigate cranking inrush brownout. This means that you
could run it until it fails to support the protected system.
I've used some FAT caps for similar tasks but they have some
special integration issues. You can't just hook these critters
to a battery to charge them . . . charging currents are very
high and tends to burn switches. You need to develop a special
current limited charging circuit to avoid the stress.
Super caps are going to REPLACE batteries in our airplanes
in the foreseeable future. But using a FAT cap to replace
a small sealed lead-acid battery in this application is
problematic.
Bob . . .
---------------------------------------------------------
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
---------------------------------------------------------
Message 13
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Subject: | Serial input transponders? |
Gang:
I am planning a minimalist glass cockpit, and find that my EFIS will
output serial altitude data directly. Anyone have a list of which
transponders will accept serial input?
I know that the Garmin GTX-327 does. What about the -320A? What about
any of the new NARCO boxes? Becker? Microair? Others? (Keep in the in
range of $2000=B1 GA units. I know that the fancier $datalink$ units
all do.) The serial-Gillman converter is about $250, which gives me
some lattitude in selecting a slightly pricier serial-compatible unit.)
Thanks,
Andy Elliott, Mesa, AZ
N601GE (reserved)
601XL/TD/QB, Corvair, building...
Message 14
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Subject: | Re: Need low cost schematic program |
Hi Bob,
Here is a site that offers 5 boards for as low as $13 per board, 5 day
turnaround. I have not yet used them (as I have not yet mastered Eagle PCB
software to the point of producing a board), but I will certainly give them
a try in the future.
http://ecommerce.pcbfabexpress.com/index.jsp
Ed
----- Original Message -----
From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
Sent: Monday, January 15, 2007 9:30 PM
Subject: Re: AeroElectric-List: Need low cost schematic program
> <nuckollsr@cox.net>
>
> At 07:52 PM 1/15/2007 -0500, you wrote:
>
>><retasker@optonline.net>
>>
>>True, but why compromise on a proprietary format when you can get Eagle
>>for free and do any layouts up to 4" x 6" with schematic capture and
>>Gerber outputs usable by any PCB house. http://www.cadsoft.de/
>>
>>Dick Tasker
>
> . . . is there a fab house that inputs Gerber plots
> that will do 5-day turnaround prototypes for $51 + 2nd
> day air?
>
> Bob . . .
>
>
>
Message 15
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Subject: | Serial input transponders? |
Dr. Elliott,
Negative on the 320/320A. Dynon produces a serial-to-parallel converter
if that helps.
Bill
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Dr.
Andrew Elliott
Sent: Monday, January 15, 2007 9:06 PM
Subject: AeroElectric-List: Serial input transponders?
Gang:
I am planning a minimalist glass cockpit, and find that my EFIS will
output serial altitude data directly. Anyone have a list of which
transponders will accept serial input?
I know that the Garmin GTX-327 does. What about the -320A? What about
any of the new NARCO boxes? Becker? Microair? Others? (Keep in the in
range of $2000=B1 GA units. I know that the fancier $datalink$ units
all
do.) The serial-Gillman converter is about $250, which gives me some
lattitude in selecting a slightly pricier serial-compatible unit.)
Thanks,
Andy Elliott, Mesa, AZ
N601GE (reserved)
601XL/TD/QB, Corvair, building...
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