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To: flyrotary@lancaironline.net
Date: Mon, 23 May 2005 21:09:48 -0400
Subject: Amps consumed data
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From: WALTER B KERR <jbker@juno.com>

Finally got around to getting batteries in the clamp on amp meter and a
run with the cowl off and someone to clamp the feed line between the
battery and alternator. The alternator was pumping 19.3 amps after
turning the alternator field on immediately after the start with
everything on in the airplane. When I switched the alternator off it went
to 0 despite some folks thinking it would continue to produce using its
on voltage to power the field. This does not happen in my case where
there is only one wire of the 3 connected to the plug. It is a battery
supply line via a switched CB to the B lead on the alternator. One of the
things I wish to get input on at Charlie's(really Tupper's) this weekend
is advice on hooking up a voltage crowbar to keep the alternator from
burning up my EC2 filter or whatever else. It seems like an easy thing to
do since shutting off this one line stops the output cold. 

After running a few minutes to get the battery charged back measured the
amps going to the bus with everything off except engine stuff and it was
6 amps at 1400 rpm and 10 amps at 4500rpm. So my 1 hour on the battery
only flight at 5000 rpm probably consumed most of the amps available in
the PC625 battery.

Still would be interesting to run a test on the ground from 11 volts till
engine dies , but want to clear this with Tracy first.

Bernie