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...

The field current is controlled by the regulator, which is usually internal. The regulator will only allow field current if the armature is spinning and bat. below about 14 volts. A small amount of current is allowed at start up via the little red light to give initial voltage.

In short get the regulator checked.

 

Ian Beadle.

 

Ian;

 

With the alternator not running, the battery voltage will always be below 14 volts; even with the charger on, so the field current will flow.  Dave has modified the internal connection the same way I did to provide external feed to the field windings.  This does not run through the warning light.  So with battery voltage to the field, alternator not running; I estimate it will draw 2-3 amps.  Plenty to make the alternator pretty warm after awhile.

 

Also, I don’t think tripping a 5 amp breaker in field circuit indicates anything wrong.  With the battery a bit low and a, say, 60A alternator spinning, the field could draw 5 amps.  I use a 7.5A breaker on my field current circuit.

 

Al