Bobby, I have seen similar problems with contactors/relays in
the past, specifically the automotive starter relays that are chassis grounded
and require +12V to activate the relay … if the +12V (battery voltage) is
weak these relays will stick ON. In my case, the starter would stay engaged so
there was no doubt about what was happening but the engine was not running …
in your case with the engine running you may not be able tell.
Why don’t you run the starter for a second or two, but do
not let the engine start (turn fuel off for example) then check your amp meter
after disengage? Jeff
From: Rotary motors in
aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Bobby J.
Hughes
Sent: Tuesday, May 12, 2009 12:36 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Starter Problem \ Question
Is
it possible for a starter to keep drawing current after engine start without
being engaged to the starter wheel? I was seeing a 38A draw today during
ground runs with only fuel, spark, EM2/3 and engine monitor turned on. Normally
I see about 15A in this condition. During ground runs last week
and running on my backup battery\ wiring I popped an 80A ANL
fuse several minutes after engine start. At the time I suspected a
hot polyfuse in a crowbar circuit for the alternator triggered the event. After
studying my wiring diagram I determined the crowbar opening could not cause the
fuse to fail. The only item capable of blowing this fuse is the starter. The
starter coil wire is in parallel with a firewall contactor coil wire. Both
coil wires go to a starter switch fused at 10A. I suspect a starter problem is
keeping voltage on the coil lead and keeping the firewall contactor closed
after engine start. My firewall contactor is not the usually starter
contactor with the small wiring terminal for the starter. It's a conventional
contactor but rated for high current. This may be part of the problem. If
the starter checks out then I will use a DC amp meter on the starter lead. I
may also add a run-on light to the coil leads.
Any
input would be appreciated.