Today's Message Index:
----------------------
1. 05:38 AM - Odyssey battery (was: Power Diode Drops) (Brian Lloyd)
2. 06:04 AM - ICOM A200 Transmit Probelm Solved: Deformed Molex Pin (John Wiegenstein)
3. 07:07 AM - antenna adapter ? (rd2@evenlink.com)
4. 07:09 AM - Re: Odyssey battery (was: Power Diode Drops) (Paul Messinger)
5. 07:22 AM - Load dump report comment (Paul Messinger)
6. 08:14 AM - Re: Digital Music in the Cockpit (Kevin Horton)
7. 08:20 AM - ICOM A200 Molex Connector (Larry McFarland)
8. 08:56 AM - Re: Digital Music in the Cockpit (Chad Robinson)
9. 09:58 AM - Re: ICOM A200 Molex Connector (qcbccgalley)
10. 10:19 AM - Re: antenna adapter ? (qcbccgalley)
11. 11:29 AM - Re: ICOM A200 Molex Connector (Larry McFarland)
12. 11:42 AM - Re: ICOM A200 Molex Connector (James Redmon)
13. 12:39 PM - Re: Load dump report comment (James Foerster)
14. 08:47 PM - LOAD DUMP report #2 (Paul Messinger)
15. 09:21 PM - Re: Load dump report comment (Robert L. Nuckolls, III)
16. 10:15 PM - Re: LOAD DUMP report #2 (Robert L. Nuckolls, III)
17. 10:34 PM - Re: Load dump report comment (Mickey Coggins)
Message 1
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| Subject: | Odyssey battery (was: Power Diode Drops) |
--> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
Paul Messinger wrote:
> --> AeroElectric-List message posted by: "Paul Messinger" <paulm@olypen.com>
>
> I suggest you look at The ODYSSEY battery. Its very different in many
> respects.
I have looked at it and, actually, it's not that different. It is an AGM battery
using the spiral-wound construction technique. This type of battery was designed
for UPS applications and has very low internal resistance right down to
final discharge allowing UPS's to use much smaller and lighter batteries than
they might otherwise need. The UPS designers don't expect them to get used much
so they accept a design that represents a high level of abuse to the battery.
Even though it has very low internal resistance it is still an AGM battery. It
is subject to the same chemistry as other AGM batteries and operates at the same
voltages. It has the same failure modes as well. Its big advantage is its
huge plate area due to the spiral-wound foil construction.
Now don't get me wrong; the Odyssey battery is quite nice and I will probably use
a pair of them in my CJ6A if I don't go with gell-cells. (I have no big starting
loads as the M14P engine uses compressed air to start.) But it is still
an AGM battery and subject to the foibles of all AGM batteries.
--
Brian Lloyd 6501 Red Hook Plaza
brianl@lloyd.com Suite 201
http://www.lloyd.com St. Thomas, VI 00802
+1.340.998.9447 (voice) +1.360.838.9669 (fax)
There is a time to laud one's country and a time to protest.
A good citizen is prepared to do either as the need arises.
Message 2
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| Subject: | ICOM A200 Transmit Probelm Solved: Deformed Molex |
Pin
--> AeroElectric-List message posted by: "John Wiegenstein" <n727jw@hellerwiegenstein.com>
After many hours of troubleshooting, I found the problem discussed in my
earlier post on this issue. The ground controller verified that I was
transmitting carrier only, as Brian Lloyd suspected in his helpful post to
my original message. I went over - again - all of the wiring between the
ICOM, the mic jacks, the Flightcom 403, etc. etc. and could not find
anything wrong. In the course of that process I verified continuity from
the "comm audio output" of the 403 to the "mic audio in" pin for the ICOM,
so the problem can't be there, can it? Oh yes it can. I later pulled the
Molex-type pin for this wire out of the ICOM's connector to verify that a
strand of shielding had not found its way up against the pin. No sign of
that, but on close inspection the "springy" portion of the pin that contacts
the radio's PCB edge connector seemed a bit squashed down into the pin body.
Hmmmmm . . . I sprung it back out, reinstalled, and VOILA! Loud and
clear transmission. I then followed Brian Lloyd's good suggestions for
dialing in the mic gain and sidetone level (factory setting for sidetone was
a bit high) and am all squared away.
This was a hard problem to track down because there's no way to test for the
physical contact between the Molex pin and the PCB at the back of the radio.
Earlier in my troubleshooting, with the radio out I looked in and could see
all the pins in place, and they were all in the right spot and looked to be
positioned correctly to make good contact with the PCB, so I did not pursue
that avenue further. But it turns out hat looks can be deceiving :-( I
don't know if this pin was bad from the start or if I damaged it in some way
in the original installation. I think Bob has mentioned before that these
type of pin and connector systems are somewhat more process-sensitive than,
say, a D-sub, and provide more opportunities for problems. It seems to me
that if a D-sub connector goes together physically then by definition you
MUST have solid electrical contact at all pins, whereas in the Molex type
connector on the ICOM you can have proper mechanical seating of the device
and yet NOT have electrical contact.
Oh well, now I know a lot more about the insides of my ICOM, and am doubly
sure that all my wiring is correct. I felt kind of dumb spending so much
time chasing so many theories/possibilities when it was a simple case of "no
connection" the whole time, but maybe this will save someone else a similar
waste of time. Brian, thanks too for your comments and feedback.
John Wiegenstein
Hansville, WA
RV-6 N727JW
Message 3
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| Subject: | antenna adapter ? |
--> AeroElectric-List message posted by: rd2@evenlink.com
In a C-172 I inherited an already installed little box that I don't know
the exact purpose of. It sits on the column near the handheld mike.
The box looks aftermarket and is labeled as "KX99 Antenna Adapter".
It has 2 BNC inputs labeled "Radio" and "Antenna" on the back and a 3.5 mm
jack on the front.
I thought it's an antenna-interrupt feed to a handheld, but neither
plugging in a 3.5 mm plug nor unplugging the Radio or Antenna BNC's does
affect the operation of the panel radios. I haven't yet checked, if the 3.5
mm jack can be used as an antenna feed to a handheld (got to make up a BNC
to 3.5 mm cable for the purpose). Any hints as to what that box could be or
do?
Thanks
Rumen
Message 4
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| Subject: | Re: Odyssey battery (was: Power Diode Drops) |
--> AeroElectric-List message posted by: "Paul Messinger" <paulm@olypen.com>
Me thinks you have the wrong battery. The ones I am talking about are
designed for starting, lighting and ignition and have an outstanding track
record. not spiral wound either.
go a google search on PC 680
In any event I have spent far too much time on this.
Paul
----- Original Message -----
From: "Brian Lloyd" <brianl@lloyd.com>
Subject: AeroElectric-List: Odyssey battery (was: Power Diode Drops)
> --> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
>
> Paul Messinger wrote:
> > --> AeroElectric-List message posted by: "Paul Messinger"
<paulm@olypen.com>
> >
> > I suggest you look at The ODYSSEY battery. Its very different in many
> > respects.
>
> I have looked at it and, actually, it's not that different. It is an AGM
battery using the spiral-wound construction technique. This type of battery
was designed for UPS applications and has very low internal resistance right
down to final discharge allowing UPS's to use much smaller and lighter
batteries than they might otherwise need. The UPS designers don't expect
them to get used much so they accept a design that represents a high level
of abuse to the battery.
>
> Even though it has very low internal resistance it is still an AGM
battery. It is subject to the same chemistry as other AGM batteries and
operates at the same voltages. It has the same failure modes as well. Its
big advantage is its huge plate area due to the spiral-wound foil
construction.
>
> Now don't get me wrong; the Odyssey battery is quite nice and I will
probably use a pair of them in my CJ6A if I don't go with gell-cells. (I
have no big starting loads as the M14P engine uses compressed air to start.)
But it is still an AGM battery and subject to the foibles of all AGM
batteries.
>
> --
> Brian Lloyd 6501 Red Hook Plaza
> brianl@lloyd.com Suite 201
> http://www.lloyd.com St. Thomas, VI 00802
> +1.340.998.9447 (voice) +1.360.838.9669 (fax)
>
> There is a time to laud one's country and a time to protest.
> A good citizen is prepared to do either as the need arises.
>
>
Message 5
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| Subject: | Load dump report comment |
--> AeroElectric-List message posted by: "Paul Messinger" <paulm@olypen.com>
I have a major choice to make.
Say nothing for 1-2 MONTHS while the report is completed and polished or put
out preliminary emails. This is after a volunteer effort. I need to get back
to personal projects and create the report in a strictly my time available
basis.
I feel that some will never be convinced of some of the conclusions and many
will be unwilling to change for many reasons.
I am trying to put out preliminary details as the report is drafted. 90-95%
of the entire effort in man hours is the documentation conversion phase from
notes and raw data to polished publication. Thus the hard proof is not
available to the detractors and defenders of the current status.
I will try the preliminary report again but IF the results are like before
(on diodes and batteries) I will likely shut up, publish the report later in
the year after the great flying season is over.
I am wondering if my choice is the best one considering all the discussions
what seems to be to be a "simple better choice" has brought in many cases.
Remember the Schottky diode thread and how long it was. The comments were
not "its a better part and/or do I need it"; But 'what I have is better' and
we do not need your part because 'a switch and special wiring' is better
than an 'automatic no pilot intervention' needed design.
The Battery thread was long in the past and has again restarted.
The informed have gravitated to the subject battery due to widespread usage
data that its a far superior part for the job. Good enough may be ok if a
battery failure is only an inconvenience but not for an electrically
dependent aircraft and or flight in solid IFR. There I want the best and not
shop price alone. But the lowest cost item that works got us to the moon.
Each takes a lot of time to reply to what I feel are incorrect conclusions
to my comments. Then there is the widespread Not invented here (NIH)
syndrome we all have in defending our past choices to any comments that
might reflect on past decisions.
Everyone needs to remember that I took on this testing even when I have way
too much to do and expected to gain nothing for my own personal use. I have
made ZERO design changes to my own electrical system but now have repeatable
test proof of the short comings of some other components and popular
designs. I do now have documentation of why I chose to do things somewhat
differently than what has been established herein.
Perhaps the biggest benefit to me was when Bob provided the DO-160 details
to me for reference use. Its a lot easier to test against established
standards than what "seems" appropriate.
There was a "demand" that any data be from a repeatable test as well as well
document. Reasonable but lots of additional work and frankly in this case
many details that seemed to me to be clear cut on inspection.
Paul
Message 6
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| Subject: | Re: Digital Music in the Cockpit |
--> AeroElectric-List message posted by: Kevin Horton <khorton01@rogers.com>
>--> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
>
>richard@riley.net wrote:
>
>> --> AeroElectric-List message posted by: richard@riley.net
>>
>> The IPOD hard disk tends to head crash above 10,000 feet with just a touch
>> of turbulence. I found out the hard way
>
>Ahh, good point. I hadn't considered that but since the heads ride
>on an air cushion, altitude is an issue. I regularly fly in the
>mid-teens.
All the hard disk equipped MP3 players would be susceptible to this
same issue. You can't cheat on the laws of physics.
--
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://go.phpwebhosting.com/~khorton/rv8/
Message 7
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| Subject: | ICOM A200 Molex Connector |
--> AeroElectric-List message posted by: "Larry McFarland" <larrymc@qconline.com>
Has anyone a source for the
pins and Molex connector that are peculiar to the
ICOM A200 radio? I've been looking and cannot
seem to find a source for these parts. The install
manual only alludes to their presence.
Larry McFarland
Message 8
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| Subject: | Re: Digital Music in the Cockpit |
--> AeroElectric-List message posted by: Chad Robinson <crj@lucubration.com>
Kevin Horton wrote:
> --> AeroElectric-List message posted by: Kevin Horton <khorton01@rogers.com>
>
>>--> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
>>
>>richard@riley.net wrote:
>>
>>
>>> --> AeroElectric-List message posted by: richard@riley.net
>>>
>>> The IPOD hard disk tends to head crash above 10,000 feet with just a touch
>>> of turbulence. I found out the hard way
>>
>>Ahh, good point. I hadn't considered that but since the heads ride
>>on an air cushion, altitude is an issue. I regularly fly in the
>>mid-teens.
>
>
> All the hard disk equipped MP3 players would be susceptible to this
> same issue. You can't cheat on the laws of physics.
Good point. If you're going to be flying this high in an unpressurized cockpit
you're best off with a Flash-based player. There are plenty of them out there,
and there are no hard drives to crash.
Regards,
Chad
Message 9
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| Subject: | Re: ICOM A200 Molex Connector |
--> AeroElectric-List message posted by: "qcbccgalley" <cgalley@qcbc.org>
I would start with local Radio Shack. If they don't have it do a google
search for Molex. Might go to Local Radio shop and ask Tim. He might have
one or can get one. Another source is Newark. Warren Radio on 23rd ave
Moline in the old Anderson Bike building probably could help. Since one can
pull the radio and take it in you have at least 1/2 of the connector. You
could also e-mail Tom Henry Tomhenry3@aol.com who used to work at Elliott's
and works for me at Oshkosh. If you have a number it would help as I have an
old Newark Catalog. You can find DigiKey and they might have what you need.
If none of these don't pan out. ask again. Bet I can come up with more.
Cy Galley - Chair, Emergency Aircraft Repair
Safety Programs Editor - TC
EAA Sport Pilot
----- Original Message -----
From: "Larry McFarland" <larrymc@qconline.com>
Subject: AeroElectric-List: ICOM A200 Molex Connector
> --> AeroElectric-List message posted by: "Larry McFarland"
<larrymc@qconline.com>
>
> Has anyone a source for the
> pins and Molex connector that are peculiar to the
> ICOM A200 radio? I've been looking and cannot
> seem to find a source for these parts. The install
> manual only alludes to their presence.
>
> Larry McFarland
>
>
Message 10
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| Subject: | Re: antenna adapter ? |
--> AeroElectric-List message posted by: "qcbccgalley" <cgalley@qcbc.org>
Hopefully you haven't transmitted with the panel radio disconnected. Your
last statement is the purpose of the antenna box. One can plug in a KX-99
or other handheld and use it to transmit and receive using the same antenna
as your panel radio. I believe that it disconnects the panel radio so you
aren't transmitting into the panel radio with your handheld.
Using an external antenna with your hand held works great.
Cy Galley - Chair, Emergency Aircraft Repair
Safety Programs Editor - TC
EAA Sport Pilot
----- Original Message -----
From: <rd2@evenlink.com>
Subject: AeroElectric-List: antenna adapter ?
> --> AeroElectric-List message posted by: rd2@evenlink.com
>
> In a C-172 I inherited an already installed little box that I don't know
> the exact purpose of. It sits on the column near the handheld mike.
> The box looks aftermarket and is labeled as "KX99 Antenna Adapter".
> It has 2 BNC inputs labeled "Radio" and "Antenna" on the back and a 3.5 mm
> jack on the front.
> I thought it's an antenna-interrupt feed to a handheld, but neither
> plugging in a 3.5 mm plug nor unplugging the Radio or Antenna BNC's does
> affect the operation of the panel radios. I haven't yet checked, if the
3.5
> mm jack can be used as an antenna feed to a handheld (got to make up a BNC
> to 3.5 mm cable for the purpose). Any hints as to what that box could be
or
> do?
> Thanks
> Rumen
>
>
Message 11
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| Subject: | Re: ICOM A200 Molex Connector |
--> AeroElectric-List message posted by: "Larry McFarland" <larrymc@qconline.com>
Thanks Cy.
The Molex address worked, now for a supplier.....tomorrow.
Mac
----- Original Message -----
From: "qcbccgalley" <cgalley@qcbc.org>
Subject: Re: AeroElectric-List: ICOM A200 Molex Connector
> --> AeroElectric-List message posted by: "qcbccgalley" <cgalley@qcbc.org>
>
> I would start with local Radio Shack. If they don't have it do a google
> search for Molex. Might go to Local Radio shop and ask Tim. He might have
> one or can get one. Another source is Newark. Warren Radio on 23rd ave
> Moline in the old Anderson Bike building probably could help. Since one
can
> pull the radio and take it in you have at least 1/2 of the connector. You
> could also e-mail Tom Henry Tomhenry3@aol.com who used to work at
Elliott's
> and works for me at Oshkosh. If you have a number it would help as I have
an
> old Newark Catalog. You can find DigiKey and they might have what you
need.
> If none of these don't pan out. ask again. Bet I can come up with more.
>
> Cy Galley - Chair, Emergency Aircraft Repair
> Safety Programs Editor - TC
> EAA Sport Pilot
> ----- Original Message -----
> From: "Larry McFarland" <larrymc@qconline.com>
> To: <aeroelectric-list@matronics.com>
> Subject: AeroElectric-List: ICOM A200 Molex Connector
>
>
> > --> AeroElectric-List message posted by: "Larry McFarland"
> <larrymc@qconline.com>
> >
> > Has anyone a source for the
> > pins and Molex connector that are peculiar to the
> > ICOM A200 radio? I've been looking and cannot
> > seem to find a source for these parts. The install
> > manual only alludes to their presence.
> >
> > Larry McFarland
> >
> >
>
>
Message 12
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| Subject: | Re: ICOM A200 Molex Connector |
--> AeroElectric-List message posted by: "James Redmon" <james@berkut13.com>
Sure do! And more...
http://www.berkut13.com/extractor.htm
James Redmon
Berkut #013 N97TX
http://www.berkut13.com
----- Original Message -----
From: "Larry McFarland" <larrymc@qconline.com>
Subject: AeroElectric-List: ICOM A200 Molex Connector
> --> AeroElectric-List message posted by: "Larry McFarland"
<larrymc@qconline.com>
>
> Has anyone a source for the
> pins and Molex connector that are peculiar to the
> ICOM A200 radio? I've been looking and cannot
> seem to find a source for these parts. The install
> manual only alludes to their presence.
>
> Larry McFarland
>
>
Message 13
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| Subject: | Re: Load dump report comment |
--> AeroElectric-List message posted by: "James Foerster" <jmfpublic@comcast.net>
Paul,
Unless you want to deal with many comments from the listers here, just say nothing
until the report is done. You already have the unnamed peer to help you,
so our comments might not add much. Many of us enjoy the running discourse, but
you have time limitations, and this is a volunteer effort on your part. No
need to feel that you must do interim reports unless you want feedback, and the
inevitable misunderstandings!
Thanks,
Jim Foerster
Message 14
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| Subject: | LOAD DUMP report #2 |
--> AeroElectric-List message posted by: "Paul Messinger" <paulm@olypen.com>
Here are the filtered out parts of DO-160 that apply to 14V systems.
A: Normal Operating conditions:
SYSTEM BUS Voltage
Max 15.1
Nominal 13.8
Minimum 11.0
B: Momentary power interruptions. 50 ms drop out.
C: BUS voltage variations
Increase to 20V for 30 ms and reduce to 7.5 volts for 30 ms.
D: Abnormal voltages steady state
Max 16.1
Nom 13.8
Min 10.0
E: Abnormal surge voltage
20V dc for one second.
F: Voltage spike
41.4V peak with a 50 ohm source impediance
Pulse Rise time 2 micro sec max and total pulse is 10 micro second
minimum.
Basically there is no requirement to operate below 11.0 Volts nor above 15.1
Volts
The equipment must survive with out damage 10.0 Volts to 16.1 Volts. and as
a added requirement survive without damage 20V for one second.
The 20V for one second is tough but the 41.4 spike is also a big energy
spike to deal with. The rise time requirement results in very high frequency
energy that does not follow low frequency filtering approaches well. It can
go right past a filter cap if one is not careful in picking the part.
The 50 ohm source impedance means that if you have a 50 ohm resistor across
the spike the voltage across the resistor is cut in 1/2. Well 1/2 is still
large and that assumes you have a input impedance of 50 ohms or less at the
50-100 MHZ spike fundamental rise frequency. Not all that easy to do.
I am still working on a spike generator as its not trivial to do to the
stated wave form requirements. Easy to overkill as the fall time has no
specified max duration. Rise time is tough due to the equivalent frequency
of the leading edge.
Its called build and test a special pulse generator. :-(
The 20V for one second is really forever to most electronics.
I have left out the battery system voltages during starting as its really a
case by case issue.
The above is a fast look as there are lots of pages to review plus my typos
and missing item. The final report will be carefully reviewed for
completeness and accuracy
Paul
Message 15
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| Subject: | Re: Load dump report comment |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 07:17 AM 6/6/2004 -0700, you wrote:
>--> AeroElectric-List message posted by: "Paul Messinger" <paulm@olypen.com>
>
>I have a major choice to make.
>
>Say nothing for 1-2 MONTHS while the report is completed and polished or put
>out preliminary emails. This is after a volunteer effort. I need to get back
>to personal projects and create the report in a strictly my time available
>basis.
>
>I feel that some will never be convinced of some of the conclusions and many
>will be unwilling to change for many reasons.
. . . I'm mystified by any perception of resistance to change for
the sake of resisting change. This is an anathema to the whole
way. If a builder doesn't like the way some part of his
project is behaving, he's ENCOURAGED to change it for the better
and do it tomorrow without waiting on anyone's permission.
>I am trying to put out preliminary details as the report is drafted. 90-95%
>of the entire effort in man hours is the documentation conversion phase from
>notes and raw data to polished publication. Thus the hard proof is not
>available to the detractors and defenders of the current status.
Perhaps I've missed reading all the posts on the subject but
I'm aware of no "detractors" . . . The issues as I perceive them
are:
(1) There's no argument that an alternator will produce an overshoot
transient when it's relieved of a load. The magnitude of that transient
is a function of RPM, alternator design, and the size of the current's
step function at the onset of the transient event.
(2) There are many suggestions in-the-wild for components suited to
to soak up the excess energy. Obviously, sizing the component depends
on transient characteristics from (1) above and design goals for
limiting ultimate voltage developed by the alternator overshoot.
>I will try the preliminary report again but IF the results are like before
>(on diodes and batteries) I will likely shut up, publish the report later in
>the year after the great flying season is over.
Don't think I saw the "first" preliminary . . . the
report needs to come in two pieces: (1) here's what we did,
here's what we measured and (2) here's what is recommended based
upon those measurements.
The first part is the repeatable experiment which is
subject to critical review taking into consideration the
test setup, measurement methods and measurement accuracy.
The second part is also subject to review to gage efficacy
of the recommendations with respect to meeting design
goals.
Common understanding of design goals was what we were missing
when you were making an argument for Schottky diodes with
application calling for use during battery-only ops. My
vision was for normal-ops with a design goal of minimizing
cost, time and risk for the neophyte user in a sitution
where power-loss was the least significant of the considerations.
>I am wondering if my choice is the best one considering all the discussions
>what seems to be to be a "simple better choice" has brought in many cases.
>
>Remember the Schottky diode thread and how long it was. The comments were
>not "its a better part and/or do I need it"; But 'what I have is better' and
>we do not need your part because 'a switch and special wiring' is better
>than an 'automatic no pilot intervention' needed design.
We were getting wrapped around the axle of deducing whether
tossing off 5 watts vis-a-vis 10 watts was a "good" thing
to do in an isolation diode. It took a number of exchanges
for me to become aware that the way you decided to use diodes
in your design had nothing to do with the way the diode was
used in designs I recommended. I was not aware that you
had incorporated didoes that were in service during
battery-only ops. Further, the architecture of the system
in your project was not one of those illustrated in Appendix Z.
The confusion was understandable. You were talking apples, I
was talking oranges and the differences in design goals were not
part of the discussion. This is nothing new . . . I see $millions$
dumped down the drain for similar reasons in the certified world
every year.
>The Battery thread was long in the past and has again restarted.
>The informed have gravitated to the subject battery due to widespread usage
>data that its a far superior part for the job.
I'm not sure I'm seeing all the list-threads. What's going on
with batteries? The AeroElectric-List traffic to my e-mail box
is a trickle of what I was getting a month ago . . .
> Good enough may be ok if a
>battery failure is only an inconvenience but not for an electrically
>dependent aircraft and or flight in solid IFR. There I want the best and not
>shop price alone. But the lowest cost item that works got us to the moon.
>
>Each takes a lot of time to reply to what I feel are incorrect conclusions
>to my comments. Then there is the widespread Not invented here (NIH)
>syndrome we all have in defending our past choices to any comments that
>might reflect on past decisions.
Not that I'm aware of . . . much of what's being done differently
today than in 1960 has evolved based on new components and
technologies that didn't exist then. These new opportunities came
about only because the OBAM aircraft community was free
of crippling regulations that carved the certified ships into
bureaucratic stone. I fully expect what's being done today will
appear just as quaint and out-of-step with the materials and ideas
available just a few years hence.
>Everyone needs to remember that I took on this testing even when I have way
>too much to do and expected to gain nothing for my own personal use. I have
>made ZERO design changes to my own electrical system but now have repeatable
>test proof of the short comings of some other components and popular
>designs. I do now have documentation of why I chose to do things somewhat
>differently than what has been established herein.
It was never clear to me in what way you were doing stuff that was so
different. Tell you what. Let's do a Z-Figure to describe your
architecture and publish it in Rev 11 along with the supporting
notes to describe the design goals. The 'Connection was never
intended to be the gospel according to Bob Nuckolls but rather
a gathering place for the best we know how to do.
>Perhaps the biggest benefit to me was when Bob provided the DO-160 details
>to me for reference use. Its a lot easier to test against established
>standards than what "seems" appropriate.
>
>There was a "demand" that any data be from a repeatable test as well as well
>document. Reasonable but lots of additional work and frankly in this case
>many details that seemed to me to be clear cut on inspection.
I don't recall anyone making demands of anybody to do anything. I
do recall a suggestion that useful conclusions are based on
data taken in a manner that anyone can repeat the experiment and
confirm good data and debunk bad data. Remember the "cold fusion"
flooby dust that circulated around the media a few years ago? Also keep
in mind that the same Chicken-Littles squawking about global
warming today were wringing their hands over a forecasted new
ice age just thirty or so years ago.
Take your time with the report . . . experience with 200,000+
airplanes over the past 55 or so years suggests that nobody's
airplane is going to come spiraling out of the sky shedding
parts and trailing smoke because of a load-dump event.
I've said this before Paul, if we do our jobs right, what we
and our contemporaries publish now will have significance to those who
read our words long after we're too senile to pound a keyboard.
Given that the current flagship publications don't know the difference
between good data and trash, then I'll suggest that the 'Connection
is the only bright star on the horizon for electrical systems.
This is not a contest but a sifting of chaos for useful
simple-ideas. A minor but learned philosopher who departed us
just a few days ago suggested that, "Good ideas are always simple,
but few are easy."
Bob . . .
Message 16
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| Subject: | Re: LOAD DUMP report #2 |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 08:46 PM 6/6/2004 -0700, you wrote:
>--> AeroElectric-List message posted by: "Paul Messinger" <paulm@olypen.com>
>
>Here are the filtered out parts of DO-160 that apply to 14V systems.
>
>A: Normal Operating conditions:
>
> SYSTEM BUS Voltage
> Max 15.1
> Nominal 13.8
> Minimum 11.0
These numbers are consistent with max lead-acid charging voltages at
very cold temperatures See page 15 of
http://www.concordbattery.com/products/technical_info/owner%20manual.pdf
(from which one may deduce that going flying with a battery that's
cold soaked to -10F or lower is NOT a good idea) and battery
state of charge (see page 17 of same document).
>B: Momentary power interruptions. 50 ms drop out.
This covers things like the momentary interruptions of battery
voltage we were talking about a few months ago . . . seems a tap of
a wrench would open the power path of about ANY contactor. See
http://www.aeroelectric.com/temp/CH10V.jpg (Cole-Hersee dropout)
and
http://www.aeroelectric.com/temp/RS10V.jpg (RBM-Stancore dropout)
>C: BUS voltage variations
> Increase to 20V for 30 ms and reduce to 7.5 volts for 30 ms.
"Load dump" and "starter motor inrush brownout"
>D: Abnormal voltages steady state
> Max 16.1
> Nom 13.8
> Min 10.0
>
> E: Abnormal surge voltage
> 20V dc for one second.
>
> F: Voltage spike
>
> 41.4V peak with a 50 ohm source impediance
> Pulse Rise time 2 micro sec max and total pulse is 10 micro second
>minimum.
I believe you're quoting Section 17 here where the 2/10 uSec
spike from a 50-ohm source is 600 volts open circuit for category
A in 28 volt systems . . . and 1/2 that value or 300 volts open
circuit for 14 volt systems.
This turns out to be a rather low energy pulse. I built the spike
generator about 25 years ago and used it one time on a certification
program. Seems that a 10 uf tantalum capacitor across the input supply
voltage to the unit under test completely wiped out the effects of this
stress.
After whipping the dragon in the first test, it didn't seem useful
to test again after a stock solution was deduced. That pulse generator
might still be laying around out at Electromech . . . if you want it
I'll see if I can pry it out of the dust.
>Basically there is no requirement to operate below 11.0 Volts nor above 15.1
>Volts
paragraph 16.5.2.1 calls for functionality down to 9.0 volts
in emergency conditions . . . of course, OBAM aircraft are never
going to suffer a 9.0 volt EMERGENCY so I don't place much
significance on this suggested benchmark.
>The equipment must survive with out damage 10.0 Volts to 16.1 Volts. and as
>a added requirement survive without damage 20V for one second.
>
>The 20V for one second is tough but the 41.4 spike is also a big energy
>spike to deal with. The rise time requirement results in very high frequency
>energy that does not follow low frequency filtering approaches well. It can
>go right past a filter cap if one is not careful in picking the part.
Figure 16-6 speaks to high energy surges. Note that category Z for
28 volt systems calls for 80 volts and 100 milliseconds and 40 volts
for about 1.5 seconds. There is no category Z graphed for 14 volt
systems but as our design goals pegged the 14 volt tests at 1/2
the 28 volt values of 40 volts for 100 milliseconds and 20-24 volts
for 1 to 1.5 seconds depending on category of the test one embraces.
>The 50 ohm source impedance means that if you have a 50 ohm resistor across
>the spike the voltage across the resistor is cut in 1/2. Well 1/2 is still
>large and that assumes you have a input impedance of 50 ohms or less at the
>50-100 MHZ spike fundamental rise frequency. Not all that easy to do.
The 50-ohm source impedance applies only to Section 17 spikes
which are intended to mimic un-bridled inductive components
like contactors and is very low energy, easy to deal with
as described elsewhere.
>I am still working on a spike generator as its not trivial to do to the
>stated wave form requirements. Easy to overkill as the fall time has no
>specified max duration. Rise time is tough due to the equivalent frequency
>of the leading edge.
>
>Its called build and test a special pulse generator. :-(
>
>The 20V for one second is really forever to most electronics.
Been doing it for years . . . piece of cake.
>I have left out the battery system voltages during starting as its really a
>case by case issue.
Nope, that's what paragraphs 16.5.2.4 and 16.5.2.5 speak to. Anything
less than
a 50 mS drop out needs to be handled by the momentary interruptions testing.
Brownouts are addressed in the paragraphs cited above. Also note the suite
of brownout test conditions specific to digital equipment cited in Table
16-1.
Finally, I'd point out Figure 16-1 AC voltage modulation on the DC power
(alternator ripple) that quite often trips up the neophyte designer.
>The above is a fast look as there are lots of pages to review plus my typos
>and missing item. The final report will be carefully reviewed for
>completeness and accuracy.
I'm wondering how much of DO-160 you're stirring into the
pot for picking a suitable component to stand off the load
dump-event on a 60A alternator. Load-dump stresses are
bounded by abnormal surge requirements of 16.5.4.4
Bob . . .
Message 17
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| Subject: | Re: Load dump report comment |
--> AeroElectric-List message posted by: Mickey Coggins <mick-matronics@rv8.ch>
Hi,
You can see if you are missing any notes by using this URL:
http://www.matronics.com/browse/aeroelectric-list/
> Given that the current flagship publications don't know the difference
> between good data and trash, then I'll suggest that the 'Connection
> is the only bright star on the horizon for electrical systems.
It sure has helped me a lot!
--
Mickey Coggins
http://www.rv8.ch/
#82007 QB Wings/Fuselage
do not archive
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