Today's Message Index:
----------------------
1. 06:50 AM - Re: E-Mag P-Mag Safety info (Robert L. Nuckolls, III)
2. 07:02 AM - Re: Re: E-Mag P-Mag Safety info - Referenced msg from Mr. Cotner (Robert L. Nuckolls, III)
3. 08:36 AM - Re: Re:B+C alternator problem (Robert L. Nuckolls, III)
4. 08:36 AM - Re: Brad's reply on P-lead switch functionality (Robert L. Nuckolls, III)
5. 09:30 AM - Re: Re: Brad's reply on P-lead switch functionality (ROGER & JEAN CURTIS)
6. 10:22 AM - Re: Re: Brad's reply on P-lead switch functionality (S. Ramirez)
7. 11:09 AM - Re: Toggle Switches with Fast-On Tabs (Jeff Page)
8. 11:55 AM - Re: Re: Toggle Switches with Fast-On Tabs (Vernon Little)
9. 01:06 PM - Re: Re: Toggle Switches with Fast-On Tabs (B Tomm)
10. 01:12 PM - Re: Re: Toggle Switches with Fast-On Tabs (Ken)
11. 01:59 PM - Re: Re: Toggle Switches with Fast-On Tabs (Vernon Little)
12. 01:59 PM - Re: Re: Toggle Switches with Fast-On Tabs (Vernon Little)
13. 04:51 PM - Re: Toggle Switches with Fast-On Tabs **Breaking News**Toggle Switches with Fast-On Tabs Toggle Switches with Fast-On Tabs Toggle Switches with Fast-On Tabs **Breaking (Tom Costanza)
14. 04:59 PM - Re: Re: Toggle Switches with Fast-On Tabs (F. Tim Yoder)
15. 06:21 PM - Re: Re: Toggle Switches with Fast-On Tabs (Vernon Little)
16. 06:26 PM - Re: Toggle Switches with Fast-On Tabs **Breaking News**Toggle Switches with Fast-On Tabs Toggle Switches with Fast-On Tabs Toggle Switches with Fast-On Tabs **Breaking (Vernon Little)
17. 06:56 PM - Re: Re: Toggle Switches with Fast-On Tabs (Mike Pienaar)
18. 07:37 PM - Re: Re: Toggle Switches with Fast-On Tabs (Dennis & Anne Glaeser)
19. 07:43 PM - Re: Re: Toggle Switches with Fast-On Tabs (S. Ramirez)
20. 07:45 PM - Re: Re: Brad's reply on P-lead switch functionality (Dale Rogers)
21. 08:16 PM - Re: Re: Toggle Switches with Fast-On Tabs (Joemotis@aol.com)
Message 1
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| Subject: | Re: E-Mag P-Mag Safety info |
I've been out of town for a couple of days an
we don't have handy access to e-mail set up yet
in M.L.
Some thoughts on the current e-mag kerfuffle:
I spoke at length with Brad at Emagair yesterday.
He was quite willing to "bare his soul" as it were
and made me privy to some facts that will probably
never be put out for public consumption. But suffice
it to say the following:
The unique failure mode that began this thread is
an rare event in the constellation of delivered
product. It involves a combination of things, some
of which may never be fully quantified because
the combination is unique to the as-installed system.
Theses are exceedingly difficult to access for
measurement, analysis and deduction of root cause.
95% of all my experiences in such matters have shown
that the fastest route to customer satisfaction is
to add robustness by redesign. After all, how difficult
is it to get a grip on an aspirin sized magnet?
The problem is centered on a limited segment of
production as outlined in this document published
on Emag's website:
http://emagair.com/E-MAG%20Service%20Bulletin%203.pdf
The mechanical issues surrounding attachment of the
position sensor magnet have been addressed and the
new attach methodology has been implemented in production,
all units returned for any kind of service are being
upgraded. Details of the new magnet mount are
shown here:
http://emagair.com/sensor%20SB.htm
There are countless situations in the history of emerging
technologies that progress is measured in more-steps-forward-
than-steps-back. We rely on lessons learned, sifting
of the simple-ideas for optimum design, test to the best
of our ability and then go to market. Ultimate success
or failure is driven by the combination of technical
prowess, manufacturing skill and honorable behavior in the
marketplace.
It's a mystery as to why a small number of installations
have experienced a cluster of failures. After all, this
configuration has been in the marketplace for over 13
months but the cluster of failures surfaced in the past
few months. As I outlined above, it's probably not in the
stars that a detailed investigation will or even can
be conducted to ascertain the combination of stresses and
limits that produced the failures.
There are individuals who have complained that their offered
expertise and talents for deducing root cause and/or remedy
were rebuffed. Any of you that have been in business will
understand that it is not a good idea to engage individuals
for problem solving that have too many dogs in the hunt.
The fact that capable and perhaps very useful talents were
not utilized is not evidence of irresponsible or dishonorable
behavior on the part of Emag.
There are individuals who for whatever reasons will suggest
there is great cause for contemplation, discussion and perhaps
even a call to action for dealing with such matters. The discussions
have already filled many keyboard-hours of participants on
the 'net. A common thread that runs through much of the
discussions I've read is the lack of data from original
sources on what happened and what's being done to fix it.
If anyone has personal concerns, call Emag and talk to
Brad or Tom. I've visited their facility and have exchanged
email and telephone conversations with them. I have no
reason to believe they're not exercising due diligence in
application of appropriate skills, talent and technology
to address a "step backwards" in the evolution of their
product. I also find no evidence of dishonorable behavior
on their part.
Finally, I'll remind readers of this List of a suggestion
I made some years ago as the Emag products first emerged.
When you buy an engine with mags, you're not likely to
get much if any rebate for leaving the mags off. Given
that 90+ percent of performance gains for EI come with
the installation of but one system, how about running one
of your mags in parallel with one Emag? When the first
mag craps, put the second mag on. Don't install dual Emags
until you've "used up" both mags.
This philosophy will allow you to exploit performance
gains offered while insulting yourself from the inevitable
effects of steps-back during the development of any
product. This mixed-technology approach to exemplary
system reliability is a tried and proven technique.
I'm not suggesting that discussions on this topic should not
continue. I do suggest that for individuals who are
gravely concerned about their own projects AVOID making a
decision based on 'net-babble. Yes, until you access
original-source-data or you are reading the analysis from
a learned writer that has access to original-source-data,
it's ALL 'net-babble.
Keep in mind too that folks who have experienced failures are
not sources of original data that goes beyond the facts of their
experience. Someone who suffers a stroke may have a great deal to
say about their experience without knowing a thing about the
simple-ideas that caused it. Their telling of the story has the
effect of raising fear of stroke on the part of listeners . . .
but adds nothing to an understanding of how risk for a similar
experience can be reduced.
Call Emag and if push comes to shove, run a Magneto/Emag combination
for awhile. Bottom line is that the sky is not falling.
Bob . . .
Message 2
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| Subject: | Re: E-Mag P-Mag Safety info - Referenced msg |
from Mr. Cotner
Only one way to find out. Ask the folks who designed it. I've
copied Brad on the query.
Brad, reply please directly to me at nuckolls.bob@cox.net
Bob . . .
At 12:19 PM 9/16/2008 -0400, you wrote:
><simon@synchronousdesign.com>
>
>Jeff, although a good point to bring up, I highly doubt that such an
>important function would go to the microprocessor, except as a status input.
>Surely it would go to a hard wired shut off circuit outside the micro to
>guarantee outside control without software being involved. If it didn't, it
>would be a major design error. However, all of these details are most
>likely proprietary data, and only Emagair would know.
>
>Simon
>Do Not Archive
>Copyright C 2008
>
>-----Original Message-----
>From: owner-aeroelectric-list-server@matronics.com
>[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Jeff Page
>Sent: Tuesday, September 16, 2008 10:32 AM
>To: aeroelectric-list@matronics.com
>Subject: AeroElectric-List: Re: E-Mag P-Mag Safety info - Referenced msg
>from Mr. Cotner
>
>
>Any possibility that grounding the P-Lead would have no effect if the
>microcontroller was way too busy handling strangely timed interrupts
>due to the timing sensor bouncing around ? That would depend on
>whether the P-Lead is a standard input read by the microcontroller, or
>goes directly to some circuitry that shuts off the spark outputs.
>Anyone know how the circuirty is designed ?
>
>Jeff Page
>Dream Aircraft Tundra #10
Message 3
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| Subject: | Re: re:B+C alternator problem |
At 08:22 AM 9/17/2008 -0700, you wrote:
>
>Bob,
>Thank you for your offer to take a look at my LR-3B. But before I
>disconnect and send it to you I was <again> poking around last night and
>noticed the "overvoltage" test switch. I see it on the wiring diagram but
>what is it or when is it used in a test mode?
Yeah, I included that in the original design as a pre-flight
test item . . . but in later years we decided that testing every
flight wasn't necessary. I think the instructions now call for
periodic testing by means of a temporary jumper or perhaps
a push-button in an off-the-panel location.
> The reason I ask is the switch appeared to be intermittent (didn't have
> a good "on-off" feel) and I figure to eliminate it from the list of
> possible faults I could cut it out of the system or replace it with a new one.
Aha! An installed switch. Yes, that COULD be a source
of your problems. Replacing it would be a valuable
experiment.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
Message 4
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| Subject: | re: Brad's reply on P-lead switch functionality |
Received a reply from Brad on functionality of the p-lead switch
in Emag products:
"Grounding the p-lead 1) sends a status signal to the processor (telling it
to stop firing), and 2) disables the driver chips (so they can't fire)."
Bob . . .
----------------------------------------
At 12:19 PM 9/16/2008 -0400, you wrote:
><simon@synchronousdesign.com>
>
>Jeff, although a good point to bring up, I highly doubt that such an
>important function would go to the microprocessor, except as a status
input.
>Surely it would go to a hard wired shut off circuit outside the micro
>to guarantee outside control without software being involved. If it
>didn't, it would be a major design error. However, all of these
>details are most likely proprietary data, and only Emagair would know.
>
>Simon
--------------------------------------
>Subject: AeroElectric-List: Re: E-Mag P-Mag Safety info - Referenced
>msg from Mr. Cotner
>
>
>Any possibility that grounding the P-Lead would have no effect if the
>microcontroller was way too busy handling strangely timed interrupts
>due to the timing sensor bouncing around ? That would depend on
>whether the P-Lead is a standard input read by the microcontroller, or
>goes directly to some circuitry that shuts off the spark outputs.
>Anyone know how the circuirty is designed ?
>
>Jeff Page
>Dream Aircraft Tundra #10
Message 5
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| Subject: | re: Brad's reply on P-lead switch functionality |
<nuckolls.bob@cox.net>
Received a reply from Brad on functionality of the p-lead switch
in Emag products:
"Grounding the p-lead 1) sends a status signal to the processor (telling it
to stop firing), and 2) disables the driver chips (so they can't fire)."
Bob . . .
Is the driver chip disable signal a "hard wired" signal to the drivers, or
is it a signal derived through the processor? It could be a problem if it
is through the processor, and the processor gets hung up by some inputs with
errors.
Roger
Message 6
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| Subject: | re: Brad's reply on P-lead switch functionality |
Thank you, Bob, for publicly responding. This redundant method of shutting
off the fire signal is a good and proven way of doing it, i.e. better than
simply shutting off the drivers as I said below.
Now the only question is why Marc Zeitlin's engine didn't quit firing? He
claims he tried to shut it off and the P-Lead was connected. Could there
have been an intermittent open in his wiring or possibly a problem in the
PMag electronics, possibly related to temperature or vibration?
Simon
Copyright 2008
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L.
Nuckolls, III
Sent: Thursday, September 18, 2008 11:36 AM
Subject: AeroElectric-List: re: Brad's reply on P-lead switch functionality
<nuckolls.bob@cox.net>
Received a reply from Brad on functionality of the p-lead switch
in Emag products:
"Grounding the p-lead 1) sends a status signal to the processor (telling it
to stop firing), and 2) disables the driver chips (so they can't fire)."
Bob . . .
----------------------------------------
At 12:19 PM 9/16/2008 -0400, you wrote:
><simon@synchronousdesign.com>
>
>Jeff, although a good point to bring up, I highly doubt that such an
>important function would go to the microprocessor, except as a status
input.
>Surely it would go to a hard wired shut off circuit outside the micro
>to guarantee outside control without software being involved. If it
>didn't, it would be a major design error. However, all of these
>details are most likely proprietary data, and only Emagair would know.
>
>Simon
Message 7
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| Subject: | Re: Toggle Switches with Fast-On Tabs |
Any chance that unsupported wires are vibrating in flight and helping
to loosen the rivets, which then heat up from poor contact ?
Jeff Page
Dream Aircraft Tundra #10
> From: "Vernon Little" <rv-9a-online@telus.net>
> The most recent information I have from the new case documented in the
> previous message is that yes, indeed, the switch rivets are loose. It
> looks like a common contributing factor.
Message 8
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| Subject: | Re: Toggle Switches with Fast-On Tabs |
Hi Jeff. This came up previously, and the answer is that they are all
supported properly. It appears that the underlying cause may be a
combination of high inrush currents and "economy" switches that start the
thermal runaway cycle: switch heating causes rivets to loosen; loose rivets
cause more switch heating.
With the exception of one switch, all of the problems have been in the
strobe and landing/taxi light circuits in multiple aircraft.
I'm hoping for more results from the list members who are checking their
switches for damage or overheating using the finger test.
Thanks, Vern
> -----Original Message-----
> From: owner-aeroelectric-list-server@matronics.com
> [mailto:owner-aeroelectric-list-server@matronics.com] On
> Behalf Of Jeff Page
> Sent: September 18, 2008 11:08 AM
> To: aeroelectric-list@matronics.com
> Subject: AeroElectric-List: Re: Toggle Switches with Fast-On Tabs
>
>
>
>
> Any chance that unsupported wires are vibrating in flight and
> helping
> to loosen the rivets, which then heat up from poor contact ?
>
> Jeff Page
> Dream Aircraft Tundra #10
>
> > From: "Vernon Little" <rv-9a-online@telus.net>
> > The most recent information I have from the new case
> documented in the
> > previous message is that yes, indeed, the switch rivets are
> loose. It
> > looks like a common contributing factor.
>
>
>
>
>
>
Message 9
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| Subject: | Re: Toggle Switches with Fast-On Tabs |
Vern,
I understand that your switches were "properly" supported. Just wondering
if the wire "support" needs to be more substantial than usual if there are
large gauge wires involved, such as would be expected for landing light
circuits? My thinking is that the larger the wire, the more momentum it has
when vibrating due to it's mass.
Secondly, maybe I've missed something here, but concerning the "loose"
rivets. It is thought that the rivets are loose because of overheating, or
vibration (with a heavy wire attached), or poor manufacturing process or
what?
Bevan
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Vernon
Little
Sent: Thursday, September 18, 2008 11:54 AM
Subject: RE: AeroElectric-List: Re: Toggle Switches with Fast-On Tabs
--> <rv-9a-online@telus.net>
Hi Jeff. This came up previously, and the answer is that they are all
supported properly. It appears that the underlying cause may be a
combination of high inrush currents and "economy" switches that start the
thermal runaway cycle: switch heating causes rivets to loosen; loose rivets
cause more switch heating.
With the exception of one switch, all of the problems have been in the
strobe and landing/taxi light circuits in multiple aircraft.
I'm hoping for more results from the list members who are checking their
switches for damage or overheating using the finger test.
Thanks, Vern
> -----Original Message-----
> From: owner-aeroelectric-list-server@matronics.com
> [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
> Jeff Page
> Sent: September 18, 2008 11:08 AM
> To: aeroelectric-list@matronics.com
> Subject: AeroElectric-List: Re: Toggle Switches with Fast-On Tabs
>
>
>
>
> Any chance that unsupported wires are vibrating in flight and helping
> to loosen the rivets, which then heat up from poor contact ?
>
> Jeff Page
> Dream Aircraft Tundra #10
>
> > From: "Vernon Little" <rv-9a-online@telus.net> The most recent
> > information I have from the new case
> documented in the
> > previous message is that yes, indeed, the switch rivets are
> loose. It
> > looks like a common contributing factor.
>
>
>
>
>
>
Message 10
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| Subject: | Re: Toggle Switches with Fast-On Tabs |
All my Carlings seem fine and run cold. 2+ years, 220 hours, AMP PIDG
connectors, Aeroflash strobes, 35 watt wigwag lights.
Ken
snip
> I'm hoping for more results from the list members who are checking their
> switches for damage or overheating using the finger test.
>
> Thanks, Vern
>
Message 11
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| Subject: | Re: Toggle Switches with Fast-On Tabs |
Good datapoint, thanks.
Vern
> -----Original Message-----
> From: owner-aeroelectric-list-server@matronics.com
> [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Ken
> Sent: September 18, 2008 1:14 PM
> To: aeroelectric-list@matronics.com
> Subject: Re: AeroElectric-List: Re: Toggle Switches with Fast-On Tabs
>
>
>
>
> All my Carlings seem fine and run cold. 2+ years, 220 hours, AMP PIDG
> connectors, Aeroflash strobes, 35 watt wigwag lights.
> Ken
>
> snip
> > I'm hoping for more results from the list members who are checking
> > their switches for damage or overheating using the finger test.
> >
> > Thanks, Vern
> >
>
>
>
>
>
Message 12
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| Subject: | Re: Toggle Switches with Fast-On Tabs |
Hey Bevan. Based on the evidence, the Strobe switch is failing in multiple
aircraft, and the Wig-Wag/Ldg/Taxi lights have a couple of failures. No
evidence in these aircraft of other switches with problems. This tends to
rule out an installation problem. The loose rivets are a both a cause and
an effect. Some of the Carling switches have somewhat loose rivets when
new. After the switch is fried, they are looser and the terminals are
discolored.
If vibration is the problem, there are many other places in the aircraft
that would show overheating (wig-wag flasher, terminal block at wing root
and so on). None do.
I think the obvious problem is the switches are being stressed by overload,
and these stresses are leading to looser rivets and further overheating. I
have new/different switches now, but if I have a failure again, I'm
installing relays.
Vern
> -----Original Message-----
> From: owner-aeroelectric-list-server@matronics.com
> [mailto:owner-aeroelectric-list-server@matronics.com] On
> Behalf Of B Tomm
> Sent: September 18, 2008 1:05 PM
> To: aeroelectric-list@matronics.com
> Subject: RE: AeroElectric-List: Re: Toggle Switches with Fast-On Tabs
>
>
>
> <fvalarm@rapidnet.net>
>
> Vern,
>
> I understand that your switches were "properly" supported.
> Just wondering if the wire "support" needs to be more
> substantial than usual if there are large gauge wires
> involved, such as would be expected for landing light
> circuits? My thinking is that the larger the wire, the more
> momentum it has when vibrating due to it's mass.
>
> Secondly, maybe I've missed something here, but concerning
> the "loose" rivets. It is thought that the rivets are loose
> because of overheating, or vibration (with a heavy wire
> attached), or poor manufacturing process or what?
>
> Bevan
>
>
>
>
> -----Original Message-----
> From: owner-aeroelectric-list-server@matronics.com
> [mailto:owner-aeroelectric-list-server@matronics.com] On
> Behalf Of Vernon Little
> Sent: Thursday, September 18, 2008 11:54 AM
> To: aeroelectric-list@matronics.com
> Subject: RE: AeroElectric-List: Re: Toggle Switches with Fast-On Tabs
>
> --> <rv-9a-online@telus.net>
>
> Hi Jeff. This came up previously, and the answer is that
> they are all supported properly. It appears that the
> underlying cause may be a combination of high inrush currents
> and "economy" switches that start the thermal runaway cycle:
> switch heating causes rivets to loosen; loose rivets cause
> more switch heating.
>
> With the exception of one switch, all of the problems have
> been in the strobe and landing/taxi light circuits in
> multiple aircraft.
>
> I'm hoping for more results from the list members who are
> checking their switches for damage or overheating using the
> finger test.
>
> Thanks, Vern
>
> > -----Original Message-----
> > From: owner-aeroelectric-list-server@matronics.com
> > [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
> > Jeff Page
> > Sent: September 18, 2008 11:08 AM
> > To: aeroelectric-list@matronics.com
> > Subject: AeroElectric-List: Re: Toggle Switches with Fast-On Tabs
> >
> >
> >
> <jpx@Qenesis.com>
> >
> > Any chance that unsupported wires are vibrating in flight
> and helping
> > to loosen the rivets, which then heat up from poor contact ?
> >
> > Jeff Page
> > Dream Aircraft Tundra #10
> >
> > > From: "Vernon Little" <rv-9a-online@telus.net> The most recent
> > > information I have from the new case
> > documented in the
> > > previous message is that yes, indeed, the switch rivets are
> > loose. It
> > > looks like a common contributing factor.
> >
> >
> >
> >
> >
> >
>
>
>
>
>
>
>
>
>
>
>
>
>
Message 13
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| Subject: | Re: Toggle Switches with Fast-On Tabs **Breaking News**Toggle |
Switches with Fast-On Tabs Toggle Switches with Fast-On Tabs Toggle
Switches with Fast-On Tabs **Breaking
Vern,
Don't you think that if it was an application problem that we'd be hearing
from people on a few orders of magnitude more than we have? There must be
several hundred people using these switches in these circuits. No??
-Tom
Message 14
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| Subject: | Re: Toggle Switches with Fast-On Tabs |
Is their a manufacturing date or any number on the switches that would let
you identify a bad batch of switches? Sounds like some switches come with
loose rivets and some don't have loose rivets. Is that correct?
The manufacture should be able to tell you if loose rivets are.acceptable.
Tim
----- Original Message -----
From: "Vernon Little" <rv-9a-online@telus.net>
Sent: Thursday, September 18, 2008 1:57 PM
Subject: RE: AeroElectric-List: Re: Toggle Switches with Fast-On Tabs
<rv-9a-online@telus.net>
>
> Hey Bevan. Based on the evidence, the Strobe switch is failing in
multiple
> aircraft, and the Wig-Wag/Ldg/Taxi lights have a couple of failures. No
> evidence in these aircraft of other switches with problems. This tends to
> rule out an installation problem. The loose rivets are a both a cause and
> an effect. Some of the Carling switches have somewhat loose rivets when
> new. After the switch is fried, they are looser and the terminals are
> discolored.
>
> If vibration is the problem, there are many other places in the aircraft
> that would show overheating (wig-wag flasher, terminal block at wing root
> and so on). None do.
>
> I think the obvious problem is the switches are being stressed by
overload,
> and these stresses are leading to looser rivets and further overheating.
I
> have new/different switches now, but if I have a failure again, I'm
> installing relays.
>
> Vern
>
>
> > -----Original Message-----
> > From: owner-aeroelectric-list-server@matronics.com
> > [mailto:owner-aeroelectric-list-server@matronics.com] On
> > Behalf Of B Tomm
> > Sent: September 18, 2008 1:05 PM
> > To: aeroelectric-list@matronics.com
> > Subject: RE: AeroElectric-List: Re: Toggle Switches with Fast-On Tabs
> >
> >
> >
> > <fvalarm@rapidnet.net>
> >
> > Vern,
> >
> > I understand that your switches were "properly" supported.
> > Just wondering if the wire "support" needs to be more
> > substantial than usual if there are large gauge wires
> > involved, such as would be expected for landing light
> > circuits? My thinking is that the larger the wire, the more
> > momentum it has when vibrating due to it's mass.
> >
> > Secondly, maybe I've missed something here, but concerning
> > the "loose" rivets. It is thought that the rivets are loose
> > because of overheating, or vibration (with a heavy wire
> > attached), or poor manufacturing process or what?
> >
> > Bevan
> >
> >
> >
> >
> > -----Original Message-----
> > From: owner-aeroelectric-list-server@matronics.com
> > [mailto:owner-aeroelectric-list-server@matronics.com] On
> > Behalf Of Vernon Little
> > Sent: Thursday, September 18, 2008 11:54 AM
> > To: aeroelectric-list@matronics.com
> > Subject: RE: AeroElectric-List: Re: Toggle Switches with Fast-On Tabs
> >
> > --> <rv-9a-online@telus.net>
> >
> > Hi Jeff. This came up previously, and the answer is that
> > they are all supported properly. It appears that the
> > underlying cause may be a combination of high inrush currents
> > and "economy" switches that start the thermal runaway cycle:
> > switch heating causes rivets to loosen; loose rivets cause
> > more switch heating.
> >
> > With the exception of one switch, all of the problems have
> > been in the strobe and landing/taxi light circuits in
> > multiple aircraft.
> >
> > I'm hoping for more results from the list members who are
> > checking their switches for damage or overheating using the
> > finger test.
> >
> > Thanks, Vern
> >
> > > -----Original Message-----
> > > From: owner-aeroelectric-list-server@matronics.com
> > > [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
> > > Jeff Page
> > > Sent: September 18, 2008 11:08 AM
> > > To: aeroelectric-list@matronics.com
> > > Subject: AeroElectric-List: Re: Toggle Switches with Fast-On Tabs
> > >
> > >
> > >
> > <jpx@Qenesis.com>
> > >
> > > Any chance that unsupported wires are vibrating in flight
> > and helping
> > > to loosen the rivets, which then heat up from poor contact ?
> > >
> > > Jeff Page
> > > Dream Aircraft Tundra #10
> > >
> > > > From: "Vernon Little" <rv-9a-online@telus.net> The most recent
> > > > information I have from the new case
> > > documented in the
> > > > previous message is that yes, indeed, the switch rivets are
> > > loose. It
> > > > looks like a common contributing factor.
> > >
> > >
> > >
> > >
> > >
> > >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
>
>
Message 15
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| Subject: | Re: Toggle Switches with Fast-On Tabs |
If you look back in the thread, I identified the date code of my switches,
and the one that Bob wrote his article on. No codes for the other failures
reported yet. We have not seen any correlation, plus one switch was made by
another vendor altogether.
I returned a failed Carling master switch for failure analysis to the
vendor, but never heard anything. It had loose rivets as well, but was not
a heavily loaded switch. Since I never heard anything, I've gone public on
this list to get some collective wisdom working on the problem.
I'm convinced that loose rivets are a big problem. I'm an electrical
engineer, not a mechanical engineer, but it's pretty obvious that the rivets
should not be loose.
Vern
> -----Original Message-----
> From: owner-aeroelectric-list-server@matronics.com
> [mailto:owner-aeroelectric-list-server@matronics.com] On
> Behalf Of F. Tim Yoder
> Sent: September 18, 2008 4:52 PM
> To: aeroelectric-list@matronics.com
> Subject: Re: AeroElectric-List: Re: Toggle Switches with Fast-On Tabs
>
>
>
> --> <ftyoder@yoderbuilt.com>
>
> Is their a manufacturing date or any number on the switches
> that would let you identify a bad batch of switches? Sounds
> like some switches come with loose rivets and some don't have
> loose rivets. Is that correct?
>
> The manufacture should be able to tell you if loose rivets
> are.acceptable.
>
> Tim
>
> ----- Original Message -----
> From: "Vernon Little" <rv-9a-online@telus.net>
> To: <aeroelectric-list@matronics.com>
> Sent: Thursday, September 18, 2008 1:57 PM
> Subject: RE: AeroElectric-List: Re: Toggle Switches with Fast-On Tabs
>
>
> <rv-9a-online@telus.net>
> >
> > Hey Bevan. Based on the evidence, the Strobe switch is failing in
> multiple
> > aircraft, and the Wig-Wag/Ldg/Taxi lights have a couple of
> failures.
> > No evidence in these aircraft of other switches with
> problems. This
> > tends to rule out an installation problem. The loose rivets are a
> > both a cause and an effect. Some of the Carling switches have
> > somewhat loose rivets when new. After the switch is fried,
> they are
> > looser and the terminals are discolored.
> >
> > If vibration is the problem, there are many other places in the
> > aircraft that would show overheating (wig-wag flasher,
> terminal block
> > at wing root and so on). None do.
> >
> > I think the obvious problem is the switches are being stressed by
> overload,
> > and these stresses are leading to looser rivets and further
> > overheating.
> I
> > have new/different switches now, but if I have a failure again, I'm
> > installing relays.
> >
> > Vern
> >
> >
> >
> > > -----Original Message-----
> > > From: owner-aeroelectric-list-server@matronics.com
> > > [mailto:owner-aeroelectric-list-server@matronics.com] On
> Behalf Of B
> > > Tomm
> > > Sent: September 18, 2008 1:05 PM
> > > To: aeroelectric-list@matronics.com
> > > Subject: RE: AeroElectric-List: Re: Toggle Switches with Fast-On
> > > Tabs
> > >
> > >
> > >
> > > <fvalarm@rapidnet.net>
> > >
> > > Vern,
> > >
> > > I understand that your switches were "properly" supported. Just
> > > wondering if the wire "support" needs to be more substantial than
> > > usual if there are large gauge wires involved, such as would be
> > > expected for landing light circuits? My thinking is that
> the larger
> > > the wire, the more momentum it has when vibrating due to
> it's mass.
> > >
> > > Secondly, maybe I've missed something here, but concerning the
> > > "loose" rivets. It is thought that the rivets are loose
> because of
> > > overheating, or vibration (with a heavy wire attached), or poor
> > > manufacturing process or what?
> > >
> > > Bevan
> > >
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: owner-aeroelectric-list-server@matronics.com
> > > [mailto:owner-aeroelectric-list-server@matronics.com] On
> Behalf Of
> > > Vernon Little
> > > Sent: Thursday, September 18, 2008 11:54 AM
> > > To: aeroelectric-list@matronics.com
> > > Subject: RE: AeroElectric-List: Re: Toggle Switches with Fast-On
> > > Tabs
> > >
> > > --> <rv-9a-online@telus.net>
> > >
> > > Hi Jeff. This came up previously, and the answer is that
> they are
> > > all supported properly. It appears that the underlying
> cause may be
> > > a combination of high inrush currents and "economy" switches that
> > > start the thermal runaway cycle: switch heating causes rivets to
> > > loosen; loose rivets cause more switch heating.
> > >
> > > With the exception of one switch, all of the problems
> have been in
> > > the strobe and landing/taxi light circuits in multiple aircraft.
> > >
> > > I'm hoping for more results from the list members who are
> checking
> > > their switches for damage or overheating using the finger test.
> > >
> > > Thanks, Vern
> > >
> > > > -----Original Message-----
> > > > From: owner-aeroelectric-list-server@matronics.com
> > > > [mailto:owner-aeroelectric-list-server@matronics.com]
> On Behalf Of
> > > > Jeff Page
> > > > Sent: September 18, 2008 11:08 AM
> > > > To: aeroelectric-list@matronics.com
> > > > Subject: AeroElectric-List: Re: Toggle Switches with
> Fast-On Tabs
> > > >
> > > >
> > > >
> > > <jpx@Qenesis.com>
> > > >
> > > > Any chance that unsupported wires are vibrating in flight
> > > and helping
> > > > to loosen the rivets, which then heat up from poor contact ?
> > > >
> > > > Jeff Page
> > > > Dream Aircraft Tundra #10
> > > >
> > > > > From: "Vernon Little" <rv-9a-online@telus.net> The
> most recent
> > > > > information I have from the new case
> > > > documented in the
> > > > > previous message is that yes, indeed, the switch rivets are
> > > > loose. It
> > > > > looks like a common contributing factor.
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> >
> >
> >
> >
> >
> >
>
>
>
>
>
>
Message 16
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|
| Subject: | Toggle Switches with Fast-On Tabs **Breaking News**Toggle |
Switches with Fast-On Tabs Toggle Switches with Fast-On Tabs Toggle
Switches with Fast-On Tabs **Breaking
Hi Tom.
We'll have to see what trickles in from the field. It could be a
combination of elements: strobe supplies, landing lights, brands of
switches, date codes of switches and a general awareness of the problem.
Give it some time. I think we'll hear more about this. We have three solid,
documented cases of similar failures, plus two more anecdotal cases. I hope
not for everyone's sake, but let's be diligent about looking for problems.
Thanks, Vern
> Vern,
>
> Don't you think that if it was an application problem that
> we'd be hearing from people on a few orders of magnitude more
> than we have? There must be several hundred people using
> these switches in these circuits. No??
>
> -Tom
>
Message 17
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| Subject: | Re: Toggle Switches with Fast-On Tabs |
Hi All,
Could somebody please explain in simple language what "high inrush currents"
are.
Thanks
Mike
----- Original Message -----
From: "Vernon Little" <rv-9a-online@telus.net>
Sent: Thursday, September 18, 2008 11:53 AM
Subject: RE: AeroElectric-List: Re: Toggle Switches with Fast-On Tabs
> <rv-9a-online@telus.net>
>
> Hi Jeff. This came up previously, and the answer is that they are all
> supported properly. It appears that the underlying cause may be a
> combination of high inrush currents and "economy" switches that start the
> thermal runaway cycle: switch heating causes rivets to loosen; loose
> rivets
> cause more switch heating.
>
> With the exception of one switch, all of the problems have been in the
> strobe and landing/taxi light circuits in multiple aircraft.
>
> I'm hoping for more results from the list members who are checking their
> switches for damage or overheating using the finger test.
>
> Thanks, Vern
>
>> -----Original Message-----
>> From: owner-aeroelectric-list-server@matronics.com
>> [mailto:owner-aeroelectric-list-server@matronics.com] On
>> Behalf Of Jeff Page
>> Sent: September 18, 2008 11:08 AM
>> To: aeroelectric-list@matronics.com
>> Subject: AeroElectric-List: Re: Toggle Switches with Fast-On Tabs
>>
>>
>>
>>
>> Any chance that unsupported wires are vibrating in flight and
>> helping
>> to loosen the rivets, which then heat up from poor contact ?
>>
>> Jeff Page
>> Dream Aircraft Tundra #10
>>
>> > From: "Vernon Little" <rv-9a-online@telus.net>
>> > The most recent information I have from the new case
>> documented in the
>> > previous message is that yes, indeed, the switch rivets are
>> loose. It
>> > looks like a common contributing factor.
>>
>>
>>
>>
>>
>>
>
>
>
Message 18
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| Subject: | Re: Re: Toggle Switches with Fast-On Tabs |
> Hi All,
> Could somebody please explain in simple language what "high inrush
currents" are.
> Thanks
> Mike
When resistive items are cold, they have less resistance. So when power is
first applied, the current draw is high - hence the name. As things warm
up, resistance grows and the current drops to it's steady state value.
Dennis Glaeser
Message 19
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| Subject: | Re: Toggle Switches with Fast-On Tabs |
Mike, a high inrush current is caused by a device that has an initial low
resistance. This resistance then increases as a function of time. I can
think of two simple devices that will do this to a switch
First is a capacitive load, or more accurately a capacitive-resistive load.
With this type of load, you are charging up a capacitor. If the capacitor
is not charged up initially, then the only thing limiting the current is the
resistor. If the resistance is small, it will result in a "high inrush
current." As the capacitor charges up, the current decreases toward zero.
Second is a non-linear resistance such as an incandescent lamp. Such a lamp
has a filament that is cold when it first passes current. When cold, the
filament has low resistance and thus allows a "high inrush current." As the
filament's temperature increases to produce light, its resistance increases,
and thus the current decreases.
There may be other simple examples and if so, anyone please feel free to
chime in. I hope this helps.
Mike, it just so happens that when a switch makes or breaks is the worst
possible time for a high current or voltage to be occurring, as it takes its
toll on the contacts due to arcing.
Simon
Copyright C 2008
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Mike
Pienaar
Sent: Thursday, September 18, 2008 9:56 PM
Subject: Re: AeroElectric-List: Re: Toggle Switches with Fast-On Tabs
Hi All,
Could somebody please explain in simple language what "high inrush currents"
are.
Thanks
Mike
----- Original Message -----
From: "Vernon Little" <rv-9a-online@telus.net>
Sent: Thursday, September 18, 2008 11:53 AM
Subject: RE: AeroElectric-List: Re: Toggle Switches with Fast-On Tabs
> <rv-9a-online@telus.net>
>
> Hi Jeff. This came up previously, and the answer is that they are all
> supported properly. It appears that the underlying cause may be a
> combination of high inrush currents and "economy" switches that start the
> thermal runaway cycle: switch heating causes rivets to loosen; loose
> rivets
> cause more switch heating.
>
> With the exception of one switch, all of the problems have been in the
> strobe and landing/taxi light circuits in multiple aircraft.
>
> I'm hoping for more results from the list members who are checking their
> switches for damage or overheating using the finger test.
>
> Thanks, Vern
>
>> -----Original Message-----
>> From: owner-aeroelectric-list-server@matronics.com
>> [mailto:owner-aeroelectric-list-server@matronics.com] On
>> Behalf Of Jeff Page
>> Sent: September 18, 2008 11:08 AM
>> To: aeroelectric-list@matronics.com
>> Subject: AeroElectric-List: Re: Toggle Switches with Fast-On Tabs
>>
>>
>>
>>
>> Any chance that unsupported wires are vibrating in flight and
>> helping
>> to loosen the rivets, which then heat up from poor contact ?
>>
>> Jeff Page
>> Dream Aircraft Tundra #10
>>
>> > From: "Vernon Little" <rv-9a-online@telus.net>
>> > The most recent information I have from the new case
>> documented in the
>> > previous message is that yes, indeed, the switch rivets are
>> loose. It
>> > looks like a common contributing factor.
Message 20
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| Subject: | Re: re: Brad's reply on P-lead switch functionality |
Robert L. Nuckolls, III wrote:
> <nuckolls.bob@cox.net>
>
> Received a reply from Brad on functionality of the p-lead switch
> in Emag products:
>
> "Grounding the p-lead 1) sends a status signal to the processor
> (telling it
> to stop firing), and 2) disables the driver chips (so they can't fire)."
Umm, that ~sounds~ good - but what does it mean? In the 30+
years that I've been working with computer hardware, I've
never run across that expression for stopping the processor.
In situations were a runaway process could result in damage,
the normal method for halting a processor isn't via a status
semaphore, but by halting the CPU clock pulse stream -
either via grounding the output of the clock, or removing
power from the clock crystal. With no clock pulses, the CPU
cannot execute instructions, period. It's the only way to be
completely certain that the CPU will in fact stop.
Dale R.
> ----------------------------------------
> At 12:19 PM 9/16/2008 -0400, you wrote:
> ><simon@synchronousdesign.com>
> >
> >Jeff, although a good point to bring up, I highly doubt that such an
> >important function would go to the microprocessor, except as a status
> input.
> >Surely it would go to a hard wired shut off circuit outside the micro
> >to guarantee outside control without software being involved. If it
> >didn't, it would be a major design error. However, all of these
> >details are most likely proprietary data, and only Emagair would know.
> >
> >Simon
> --------------------------------------
> >Subject: AeroElectric-List: Re: E-Mag P-Mag Safety info - Referenced
> >msg from Mr. Cotner
> >
> >
> >Any possibility that grounding the P-Lead would have no effect if the
> >microcontroller was way too busy handling strangely timed interrupts
> >due to the timing sensor bouncing around ? That would depend on
> >whether the P-Lead is a standard input read by the microcontroller, or
> >goes directly to some circuitry that shuts off the spark outputs.
> >Anyone know how the circuirty is designed ?
> >
> >Jeff Page
> >Dream Aircraft Tundra #10
>
Message 21
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| Subject: | Re: Toggle Switches with Fast-On Tabs |
Does anyone with these switches in question also have a laser thermometer to
shoot their switch bank with?
Might be interesting although not very scientific.
Most assuredly would find a hot one though.
Joe Motis Do not archive
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