Today's Message Index:
----------------------
1. 06:02 AM - Re: Anti Corrosive Zinc Paste (Eric M. Jones)
2. 07:51 AM - ELT current demand ()
3. 08:08 AM - Re: ELT current demand (John Morgensen)
4. 01:20 PM - Re: ELT current demand (Werner Schneider)
5. 04:08 PM - Re: Anti Corrosive Zinc Paste (Henador Titzoff)
6. 09:43 PM - LEMO and "transformer coupled audio" (Dave Saylor)
Message 1
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Subject: | Re: Anti Corrosive Zinc Paste |
I looked up Penetrox and there are several types; some for copper-to- copper, some
for aluminum-to-copper or aluminum-to-aluminum.
Some history here is required: Years ago we experimented with materials that contained
suspended copper or silver for the purpose of heat sinking large Xenon
lamps, while simultaneously conducting current (>20A). Here what happened: KA-BLAM-O!!!
So we slinked back to using zinc oxide in silicone oil and no more problem. Why
we thought suspended metal particles was a good idea is obvious...and wrong.
What happened was that the suspended metal particles conducted current while simultaneously
preventing the really big flat contacts from mating. And the current
you can conduct with thousands of microscopic particles is quite limited.
So: Using goop with suspended metal particles is probably a good idea at low current
and modest voltage...like a connection to aluminum antennae, or Al-Cu pigtails
in homes wired with aluminum. But it's probably a really bad idea with
high currents at low voltages. Of course this depends on the size of the particles,
the materials and hardness of the connectors and the pressure of the joint.
But I wouldn't use the metal-particle goop without thinking about it carefully.
--------
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=373466#373466
Message 2
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Subject: | ELT current demand |
Cheers,
I have not yet chosen the model of ELT for inclusion on my Europa,
but must make way for its eventual installation. That means fuse and wire
size choice.
Rather than spend time researching hesitant advertisers, I'm asking
for your advice on the current requirement of your or any ELT.
I am aware of the transmit level but of course it's for such a short time
that there must be an average level plus safe margin with which to work.
Thanks in advance.
Ferg
C-FFGG mono 914 CS prop
Message 3
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Subject: | Re: ELT current demand |
The ELT is self-contained and battery operated. The installation
concerns are antenna location and periodic replacement of the batteries.
john
On 5/21/2012 7:53 AM, f.kyle@sympatico.ca wrote:
> Cheers,
> I have not yet chosen the model of ELT for inclusion on my Europa,
> but must make way for its eventual installation. That means fuse and wire
> size choice.
> Rather than spend time researching hesitant advertisers, I'm asking
> for your advice on the current requirement of your or any ELT.
> I am aware of the transmit level but of course it's for such a short time
> that there must be an average level plus safe margin with which to work.
> Thanks in advance.
> Ferg
> C-FFGG mono 914 CS prop
>
Message 4
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Subject: | Re: ELT current demand |
Plus connection to the remote panel/buzzer
On 21.05.2012 17:06, John Morgensen wrote:
> <john@morgensen.com>
>
> The ELT is self-contained and battery operated. The installation
> concerns are antenna location and periodic replacement of the batteries.
>
> john
>
> On 5/21/2012 7:53 AM, f.kyle@sympatico.ca wrote:
>> Cheers,
>> I have not yet chosen the model of ELT for inclusion on my Europa,
>> but must make way for its eventual installation. That means fuse and wire
>> size choice.
>> Rather than spend time researching hesitant advertisers, I'm asking
>> for your advice on the current requirement of your or any ELT.
>> I am aware of the transmit level but of course it's for such a short time
>> that there must be an average level plus safe margin with which to work.
>> Thanks in advance.
>> Ferg
>> C-FFGG mono 914 CS prop
>>
>
>
Message 5
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Subject: | Re: Anti Corrosive Zinc Paste |
Thanks, Eric, I appreciate your analytic approach to our problems, with tes
ts to determine validity.=0A=0AToday I went to AutoZone and bought some Per
matex Dielectric Grease in an 8 oz squeeze tube. -It should last me for s
everal years.=0A=0AAlso, today I saw three local electric utility guys get
out of a Chevrolet souped up truck and start looking at one of their boxes.
-Two of them seemed to know what they were doing, while one was studying
what I was doing, which was studying what they were doing. I walked across
the street and asked them what they were doing, and he said that Engineeri
ng was looking at a switch box to see how it functioned. -I asked him wha
t it was switching, and he said 12,000V. -I asked him how it got stepped
down to 240V and 120V, and he said he didn't know. -He asked one of the o
ther guys, and they started looking around, finally spotting a box about tw
o doors down. -He said that box was a step down transformer. -I asked h
im if he knew what Penetrox or No-Ox-ID was, and he said no and asked me wh
at they were. I told him they were pastes with zinc used to coat aluminum w
ires to keep them from corroding, and he said he had heard of something lik
e that. -I'm not
sure where they dug up this fossil, but for an electric utility engineer,
he didn't know squat about his company's technology. -I'm now guessing he
was a mismanager.=0A=0AHenador Titzoff=0A=0A=0A___________________________
_____=0A From: Eric M. Jones <emjones@charter.net>=0ATo: aeroelectric-list@
matronics.com =0ASent: Monday, May 21, 2012 9:00 AM=0ASubject: AeroElectric
-List: Re: Anti Corrosive Zinc Paste=0A =0A--> AeroElectric-List message po
sted by: "Eric M. Jones" <emjones@charter.net>=0A=0AI looked up Penetrox an
d there are several types; some for copper-to- copper, some for aluminum-to
-copper or aluminum-to-aluminum. =0A=0ASome history here is required: Years
ago we experimented with materials that contained suspended copper or silv
er for the purpose of heat sinking large Xenon lamps, while simultaneously
conducting current (>20A). Here what happened: KA-BLAM-O!!!=0A=0ASo we slin
ked back to using zinc oxide in silicone oil and no more problem. Why we th
ought suspended metal particles was a good idea is obvious...and wrong.=0A
=0AWhat happened was that the suspended metal particles conducted current w
hile simultaneously preventing the really big flat contacts from mating. An
d the current you can conduct with thousands of microscopic particles is qu
ite limited.=0A=0ASo: Using goop with suspended metal particles is probably
a good idea at low current and modest voltage...like a connection to alumi
num antennae, or Al-Cu pigtails in homes wired with aluminum. But it's prob
ably a really bad idea with high currents at low voltages. Of course this d
epends on the size of the particles, the materials and hardness of the conn
ectors and the pressure of the joint. =0A=0ABut I wouldn't use the metal-pa
rticle goop without thinking about it carefully.=0A=0A--------=0AEric M. Jo
nes=0Awww.PerihelionDesign.com=0A113 Brentwood Drive=0ASouthbridge, MA 0155
0=0A(508) 764-2072=0Aemjones(at)charter.net=0A=0A=0A=0A=0ARead this topic o
nline here:=0A=0Ahttp://forums.matronics.com/viewtopic.php?p=373466#37346
=
Message 6
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Subject: | LEMO and "transformer coupled audio" |
We've wired quite a few planes with powered LEMO jacks for Bose and
Lightspeed headsets. It's usually a very straightforward case of
piggybacking the audio onto the existing mic and phone jacks, and
adding a power wire. The noise canceling circuit normally grounds
through the audio lo and works very well.
But we recently had a case where the aircraft had "transformer coupled
audio". The Bose instructions warn you about this but don't really
say what to do about it. What happens is, the noise canceling circuit
doesn't see a ground so it doesn't turn on. In our case we just had
to run the power ground (as opposed to audio ground) to a local
airframe ground, and it worked just fine.
Dave Saylor
831-750-0284 CL
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