Subject: Re: (Avionics) How can this circuit produce an "inductive surge"?
Date: Thu, 26 Sep 2002 23:23:19 +0100
NNTP-Posting-Date: Thu, 26 Sep 2002 22:22:16 +0000 (UTC)
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Mike Poulton wrote
>The current draw when starting is huge. Hundreds of amps. That's
>enough that the battery voltage sags well below the reset voltage for
>most all the electronics attached to it. Consequently, they would reset
>anyways -- why not shut them off completely to reduce drain? Also, the
>starter is an inductive load. When it turns off, it will produce a high
>voltage across the starter relay. Depending on how things are wired
>(and where other wires go) this could conceivably cause a spike in the
>12V system, or in other circuitry (sensor wires, etc.).
What I am trying to find out is how things need to be wired for this
In any event, let's say that something to do with the starter motor
does cause a problem. It could be arcing on the starter relay contacts
which injects a lot of RF into the wiring, I accept that. But the
starter is not used at engine turnoff, yet all the checklists I have
seen require disconnection of just about everything at engine shutdown
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