Subject: Re: (Avionics) How can this circuit produce an "inductive surge"?
Date: Thu, 26 Sep 2002 22:22:36 +0100
Organization: (Posted via) GTS Netcom.
NNTP-Posting-Date: Thu, 26 Sep 2002 21:16:15 +0000 (UTC)
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Jim Weir wrote:
>That also is true. On engine startup, that magnetic field collapses in a big
>way when the starter motor is de-energized after the engine starts.
When the starter motor is de-entergised, it is also at the same time
disconnected. How can the de-energisation of the starter motor produce
a spike on the avionics supply? Especially as the battery is still
connected into the circuit.
>shutdown, the master switch relay dumps a hell of a spike onto a system that has
>just had the massive spike absorber called a battery removed from the circuit.
The master relay coil (which AIUI, and certainly in my case, is used
to connect the battery to the rest of the aircraft) is powered from
the *battery* side of the master relay, so de-energising the master
relay would dump the energy into the battery, not into the circuit
that has just been disconnected.
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