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Message-ID: <1c23473f050513194511879e7e@mail.gmail.com>
Date: Fri, 13 May 2005 19:45:39 -0700
From: David Leonard <wdleonard@gmail.com>
Reply-To: David Leonard <wdleonard@gmail.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Hot Alternator???
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I am leaving for a long cross country in the morning and while doing
pre-flight I noticed something interesting today.  I had been running
the fuel pump on battery while troubleshooting a fuel pressure sensor
issue.  Since I didn't want to risk not having enough juice for start
in the a.m. so I hooked up the charger, which requires keeping the
master on.

During the rest of the pre-flight I happened to brush up against the
alternator and discovered that it was very warm to the touch. (engine
had not been run in days)  The battery charger was only showing about
6 amps including the master contactor, charging the battery, and the
master buss, so there was not an exorbitant amount of current going
through the alternator.  The pulley was hot enough that I couldn't
hold it for long.

I have modified my alternator according to the directions Ed sent to
be able to switch the field coil on and off manually..  During initial
flight testing I discovered that the alternator field was using more
than the 5 amp breaker I had installed, so the alternator field is
temporarily wired directly to the main buss.

For those of you in the know, is it normal for an alternator to seep
current and get warm when the field coil is powered up?  Is this
something I need to fix?  If so, should I cancel my trip?  I think it
has probably been going on for a long time but...

Dave Leonard