Today's Message Index:
----------------------
1. 04:52 AM - Re: Vans EGT gauge not working... (racerjerry)
2. 08:05 AM - Re: Re: Vans EGT gauge not working... (R&J. Curtis)
3. 09:44 AM - Re: Tyco W31 switch / breaker (Eric M. Jones)
4. 09:53 AM - Re: Re: Vans EGT gauge not working... (Robert L. Nuckolls, III)
5. 06:06 PM - Re: Re: Tyco W31 switch / breaker (Dj Merrill)
6. 08:37 PM - Re: Tyco W31 switch / breaker (Vern Little)
7. 09:40 PM - Fuse holders (Alan Barnett)
8. 09:52 PM - Re: COZY: Fuse holders (Tim Andres)
Message 1
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Subject: | Re: Vans EGT gauge not working... |
> 1) Verified power and ground to the gauge.
>
As far as I know, power to simple analog EGT/CHT indicating systems are for internal
lighting only.
First of all, its much easier to test the EGT system by removing the sender from
the exhaust system and heating the tip with a propane torch to see if you get
needle movement need another person in the cockpit to watch gauge. Please
use some precautions here so as to not burn your airplane nor anyone elses down.
A fire extinguisher AND a handy 5 gal bucket of water along with common sense
can work wonders.
If that didnt work, the next thing to do is reverse the wires and recheck. Yeah,
I know, color code, yadda yadda Reverse the wires, reheat and see if needle
moves
If that still dont work, disconnect wires from the gauge and check for continuity
at the wires. By measuring the wires, you are checking the sender and any
extension leads and eliminating everything except the gauge.
My Westach setup says sender resistance should be about 2.5 ohms for EGT, but meter
lead resistance will add to this, so correct reading will be higher. You
are really looking for continuity at this point. Now if all appears to be roughly
correct, you could turn your digital meter to the millivolt scale, reheat
the EGT probe and watch for a tiny millivolt output within seconds of applying
flame.
The gauge itself can be checked for continuity with a DIGITAL ohmmeter (the gauge
is so sensitive that an analog meter can burn the darned thing out).
Let me repeat - Test gauge using ONLY a digital ohmmeter
Again, you are just looking for continuity, but Westach says somewhere between
8 & 15 ohms.
Resistance readings may differ as EGT systems may use either J or K type thermocouples
(sender), but you are mainly looking for continuity. These things generally
either work well or not at all.
Any resistance in the system or any corrosion will generally result in no or very
low indication
--------
Jerry King
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=424509#424509
Message 2
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Subject: | Re: Vans EGT gauge not working... |
>
> As far as I know, power to simple analog EGT/CHT indicating systems are
> for internal lighting only.
>
> First of all, it?Ts much easier to test the EGT system by removing the
> sender from the exhaust system and heating the tip with a propane torch to
> see if you get needle movement ?" need another person in the cockpit to
> watch gauge. Please use some precautions here so as to not burn your
> airplane nor anyone elses down. A fire extinguisher AND a handy 5 gal
> bucket of water along with common sense can work wonders.
>
> If that didn?Tt work, the next thing to do is reverse the wires and
> recheck. Yeah, I know, color code, yadda yadda ?" Reverse the wires,
> reheat and see if needle moves
>
> If that still don?Tt work, disconnect wires from the gauge and check for
> continuity at the wires. By measuring the wires, you are checking the
> sender and any extension leads and eliminating everything except the
> gauge.
>
> My Westach setup says sender resistance should be about 2.5 ohms for EGT,
> but meter lead resistance will add to this, so correct reading will be
> higher. You are really looking for continuity at this point. Now if all
> appears to be roughly correct, you could turn your digital meter to the
> millivolt scale, reheat the EGT probe and watch for a tiny millivolt
> output within seconds of applying flame.
>
> The gauge itself can be checked for continuity with a DIGITAL ohmmeter
> (the gauge is so sensitive that an analog meter can burn the darned thing
> out).
> Let me repeat - Test gauge using ONLY a digital ohmmeter
>
> Again, you are just looking for continuity, but Westach says somewhere
> between 8 & 15 ohms.
>
> Resistance readings may differ as EGT systems may use either J or K type
> thermocouples (sender), but you are mainly looking for continuity. These
> things generally either work well or not at all.
>
> Any resistance in the system or any corrosion will generally result in no
> or very low indication
Just one other thought on this. If you added an extension
wire to the probe MAKE SURE that you used the proper wire.
If it is a "J" type, Red and White wires, be certain that you use
the red and white thermocouple extension wires. Use of other
wires can give you gross errors.
Roger
Message 3
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Subject: | Re: Tyco W31 switch / breaker |
> However, the person that wired this aircraft originally hooked them up
> backwards, with the copper bus bar connected to the "Load" terminal, and
> the devices being switched connected to the "Line" terminal.
> My question is, does it really matter?
Some plumber installed an angle valve that had an arrow on the body. He installed
it with the arrow pointing in the wrong direction. How did I learn this? Because
the water pressure kept the valve washer stuck to the valve seat so opening
the valve unscrewed the washer retaining screw. The valve quit working.
Electricians know that a 3-wire flexible cord can only be attached to one end of
the cord. Although you might think that a power cord comes out of each end identically,
they are actually mirror images. Only one end installs onto (for example)
hospital-grade plugs.
MAYBE W31 circuit breakers have a proper line and load connection orientation because
the conducting parts, arc suppression, hi-voltage withstand, inductive
load, capacitance, wet operation, voltage breakdown to ground (or to the toggle),
electrical approvals, or God-knows-what-else behaves somewhat differently
in the opposite direction.
Maybe this matters and maybe not. But if it doesn't matter, why did they mark it
that way? Only the P&B/Tyco engineers can tell you and it would certainly be
worth an email to find out.
Please share it with us.
--------
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=424516#424516
Message 4
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Subject: | Re: Vans EGT gauge not working... |
At 06:50 AM 6/8/2014, you wrote:
<gki@suffolk.lib.ny.us>
> 1) Verified power and ground to the gauge.
>
As far as I know, power to simple analog EGT/CHT
indicating systems are for internal lighting only.
Van's line of analog instruments are built on
a common frame of circuitry used to position
pointers over approx 250 degrees of arc on
the dial.
Emacs!
An exemplar instrument (ammeter) was examined
in our shop some years back . . .
http://tinyurl.com/mpx8hze
This particular device was found to be rather sensitive to
strong fields of radio frequency energy in
the cockpit . . .
First of all, it=99s much easier to test the EGT
system by removing the sender from the exhaust
system and heating the tip with a propane torch
to see if you get needle movement =93 need
another person in the cockpit to watch
gauge. Please use some precautions here so as to
not burn your airplane nor anyone elses down. A
fire extinguisher AND a handy 5 gal bucket of
water along with common sense can work wonders.
If that didn=99t work, the next thing to do is
reverse the wires and recheck. Yeah, I know,
color code, yadda yadda =93 Reverse the wires, reheat and see if
needle moves
If that still don=99t work, disconnect wires from
the gauge and check for continuity at the
wires. By measuring the wires, you are checking
the sender and any extension leads and
eliminating everything except the gauge.
My Westach setup says sender resistance should be
about 2.5 ohms for EGT, but meter lead resistance
will add to this, so correct reading will be
higher. You are really looking for continuity at
this point. Now if all appears to be roughly
correct, you could turn your digital meter to the
millivolt scale, reheat the EGT probe and watch
for a tiny millivolt output within seconds of applying flame.
The gauge itself can be checked for continuity
with a DIGITAL ohmmeter (the gauge is so
sensitive that an analog meter can burn the darned thing out).
Let me repeat - Test gauge using ONLY a digital ohmmeter
Not true . . . the non-electronic instruments designed
to read millivolt levels DIRECTLY from a heated thermocouple
have VERY low winding resistance as matter of necessity . . .
as panel instruments they are generally designed for
full scale indication with only tens of millivolts
applied to the terminals at TENS of milliamps. "Self powered"
instruments of yesteryear were often calibrated assuming
thermocouple lead wires long enough to reach to the extreme
engine locations on a large airplane. Lead wires for closer
engines could be shortened and the lost-resistance
compensated for by inserting a "thermocouple spool
resistor" in one lead.
http://www.dfwairparts.com/images/avionics/Aircraft_Thermocoupl
The resistor was shipped with some too-large value (about 10 ohms
as I recall). The installing technician could remove the
cover and peel off turns of wire on the spools underneath
the cover until the desired calibration was achieved.
Again, you are just looking for continuity, but
Westach says somewhere between 8 & 15 ohms.
The input terminal to a Van's EGT will be considerably
higher resistance. Signal conditioners inside the instrument
are designed for insensitivity to total loop resistance
of the thermocouple signal . . . this is goes to the
goal of allowing thermocouples to be extended by any
practical length without concern for instrument
calibration as described above.
Bob . . .
Message 5
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Subject: | Re: Tyco W31 switch / breaker |
On 6/8/2014 12:41 PM, Eric M. Jones wrote:
> Only the P&B/Tyco engineers can tell you and it would certainly be worth an email
to find out.
True, but I had my doubts that I'd find out the answer over the
weekend, and waiting until Monday would have cost me an entire day's
worth of work on the plane. With the collective wisdom of this group, I
figured I had a chance that someone might know.
> MAYBE W31 circuit breakers have a proper line and load connection orientation
because the conducting parts, arc suppression, hi-voltage withstand, inductive
load, capacitance, wet operation, voltage breakdown to ground (or to the toggle),
electrical approvals, or God-knows-what-else behaves somewhat differently
in the opposite direction.
>
Yes, this paralleled my own thoughts, and the first thing I did
this morning was to re-wire everything the "right" way. It cost a
couple of hours of effort, but my anal-retentiveness kept bugging me so
it was worth it. Even if they were fine the other way, now my I's are
crossed and my T's are dotted... ;-)
Thanks for the replies, guys!
-Dj
--
Dj Merrill - N1JOV - VP EAA Chapter 87
Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/
Glastar Flyer N866RH - http://deej.net/glastar/
Message 6
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Subject: | Re: Tyco W31 switch / breaker |
Furthermore, if it was important it would be specified in the datasheet,
which it is not. Even the writing on the breaker is not specified, so it's
technically not part of the device.
If you used a breaker to tie two electrical buses together and it had a
polarity, what would you do? It doesn't matter with these guys.
Vern
-----Original Message-----
From: Sprocket
Sent: Saturday, June 07, 2014 6:24 PM
Subject: Re: AeroElectric-List: Tyco W31 switch / breaker
It doesn't matter. These are thermal breakers so current direction can run
either way.
Vern
===================================================
Sent from my iThing. It is responsible for all gramma and typo terrors.
> On Jun 7, 2014, at 5:50 PM, Dj Merrill <deej@deej.net> wrote:
>
>
> I am in the process of refurbishing the panel in my aircraft, which uses
> Tyco W31 switch/breakers for some items
> (https://www.aircraftspruce.com/catalog/elpages/pbcircuitbrkr2.php). I
> noticed that the W31 terminals are labeled "Line", which I presume is for
> the electrical bus, and "Load", which I presume is for the device being
> switched.
>
> However, the person that wired this aircraft originally hooked them up
> backwards, with the copper bus bar connected to the "Load" terminal, and
> the devices being switched connected to the "Line" terminal.
>
> My question is, does it really matter?
>
> If it does, now would be the time to rewire since I have it all apart,
> however, the way it is hooked up at present does make for a neater and
> cleaner installation. It has been flying this way for over 15 years, but
> if it is "wrong", then I should probably make it "right".
>
> Thanks,
>
> -Dj
>
> --
> Dj Merrill - N1JOV - VP EAA Chapter 87
> Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/
> Glastar Flyer N866RH - http://deej.net/glastar/
>
>
Message 7
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I need to add circuit protection for my new avionics. I have no room in
the panel, so I plan to put fuses behind the panel. I need suggestions
for which fuse holder I should use. Is a fuse block preferable to
inline fuse holders? What models do you recommend?
Thanks for your help.
Alan
Message 8
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Subject: | Re: COZY: Fuse holders |
ATC or ATM fuses are more durable than glass fuses and are becoming much more common.
I'd put them in a device like this from B&C:
http://www.bandc.biz/fuseholder8-slot.aspx
Tim Andres
> On Jun 8, 2014, at 9:39 PM, Alan Barnett <alansbarnett@verizon.net> wrote:
>
> I need to add circuit protection for my new avionics. I have no room in the
panel, so I plan to put fuses behind the panel. I need suggestions for which
fuse holder I should use. Is a fuse block preferable to inline fuse holders?
What models do you recommend?
>
> Thanks for your help.
>
> Alan
>
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