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From: "Ed Anderson" <eanderson@carolina.rr.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-727760@logan.com>
Subject: Re: [FlyRotary] Re: Bernie update on N19VX (blowing chips)
Date: Sun, 13 Feb 2005 21:38:14 -0500
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Bernie,

A faulty switch could certainly be the problem - just a chip of metal in the
casing that could short a couple of pins in the switch just for a tiny
fraction of second would do it.  Also some of the "Make-before-Break" are
"spring" loaded such that the "Make and Break" happen in 10s of
milliseconds, so it might not register on anything less than an oscilloscope
type instrument.  The fact that you are apparently not frying any more chips
with your single switch would to me strongly indicate:

1.  Wiring error (which I would consider highly unlikely the number of times
you have been over the wiring)
2.  A defective switch (which might account why the EC2 survived for at
least some amount of time before blowing)
3.  A "Make - before-Break" switch(es) in the batch of three

Ed A
----- Original Message -----
From: <jbker@juno.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Sunday, February 13, 2005 9:19 PM
Subject: [FlyRotary] Re: Bernie update on N19VX (blowing chips)


>
> We suspicion that one of the double pole double throw switches has a
momentary short from the 12 volt side to the ground side, but I can not
confirm it with a voltmeter. The digital voltmeter probably averages several
samples, but I never see a rise when I activate the switch very slowly.
Tried an old analog gage and still could not identify it. Tracy is convinced
that we are hitting the circuit on the chip with 12 volts to blow it. Now
that I have the simple one toggle switch, no more chips have been blown in
nearly an hour of running over the last two days. With the 3 switches hooked
to pin 30 it was instantaneous death.
>
> The switches are either from B&C or an orlando aircraft surplus shop. The
two sources for switches appear to come from the same Mexican supplier, but
do not know the details other than appearance.
>
> Bernie
>
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