OK you A&P's,,riddle me this. 10 minutes after departure yesterday I establish my cruise altitude and start setting up for cruise. As I scan the panel I see two disturbing things. #1 My Amps gauge is dead center on Zero. #2 My "Field" breaker is popped out. I have two breakers for my alternator "Output" & "Field". After pushing the "Field" breaker back in, my Amps gauge immediately jumps to around 30amps. After 10sec, it pops again. Upon returning to the airport, I shut EVERYTYHING electrical off but the master, push the breaker back in and it still pops. Next I try it with the master off and it remains IN. Any idea as to what this could be?? Appreciate the feedback.
Doug, Do you have the service manual? I can direct you to a copy of it. Let me know. On the Arrow ( dont know what you have) the field wire starts at the Alternator. The manual says to disconnect the field wire at the alternator and turn on the master. If the CB doesn't pop it is the alternator. If it pops then you have to continue to the next section of wire in line to the CB. I will try to copy the exact wording of the SM.
Field circuit breaker
trips.
Disconnect field wiring circuit. at terminal of alternator.
Turn on master switch. If breaker continues to trip, proceed
to disconnect each leg of field circuit, working from the alternator
towards the circuit breaker until breaker can be reset and will hold. Replace component or wire which was isolated as defective. (See wiring
schematic. )
Short circuit in field winding of alternator.
Disconnect field wiring at terminal of alternator. Turn on master
switch. Reset breaker and if breaker fails to retrip, this isolates
short circuit to field of alternator itself. Check brush holders for
shorting against frame. If there are no obvious signs of a physical
short circuit at field terminal or brush holder, replace alternator.
(Note: Intermittent
short circuit.)
Internal short circuiting of the field can occur at various positions of
the rotor, therefore, reconnect field, reset breaker, pull propeller
slowly by hand turning alternator rotor through 360° of travel. Observe
circuit breaker for signs of trippiTurn magneto switch to off before turning propeller
