><< Beechcraft Barons and Bonanzas have had a 'starter engaged' light on the
> panel for several years, and many have been added to older craft. A wire
> from the starter relay ouput to a small lamp on the panel is all that is
> needed. >>
>
>The checklist for the C-planes at the school were I teach part-time include a
>check after starting that the starter is disengaged by turning off the
>alternator side of the master switch and seeing if there is a strong charge
>indication (from the starter being driven as a generator). Would that do the
>job for us, too?
This is a myth that has been given too much fertilizer . . . a stuck
starter solenoid does indeed keep the motor spinning . . . however,
over-running clutches in virtually all starters are absolutely necessary
to prevent the engine from distroying the starter. Recall that cranking
RPMs are about 500, during this time, the starter's armature is running
at about it's design speed. Now, if you start the engine and throttle
up to say 2500 rpm, if the starter were firmly geared to the engine,
it would now be running 5x it's design speed . . . guarantee it's
windings will come right out of the slots, gears strip, etc, etc,.
If your starter contactor does stick -AND- your airplane is fitted
with an ammeter, you will see higher than normal "charging" loads
on an ammeter because the starter is connected directly to the battery
and appears to the alternator as a severely discharged battery - -
so of course the ammeter lays over harder. If you turn off the alternator,
I'll guarantee you the ammeter will lay back to zero . . . or if its
a minus-zero-plus battery ammeter, it will show a discharge if system
goodies are on.
Even if the starter contactor IS stuck, you'll get the same result.
Whoever started this rumor has done his fellow flyers a terrible
disservice because the "test" has no way to confirm contactor sticking.
Indeed, the test will ALWAYS indicate a-not-stuck contactor.
If inquiring minds really want to know, a starter engaged light
on the panel is the best way.
Bob . . .
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