ALT FIELD Voltage Problem & Breaker engaged

[Philip France 13]

Hello on a flight from Marseille France to San Lluis Menorca under IFR FLIGHT  : the ALT voltage red lamp Went ON and ALT FIELD breaker engaged. Tried to push the breaker it did pop out immediately. I decided to divert to LFMP Perpignan where i landed without problem. On the ground went to repair station we found the battery power connector was lose we tighten it properly and the problem seemed to be fixed. Made a new flight plan and when for refueling after few minutes same issue came back. I do believe the voltage regulator failed after testing again no more voltage was supplied. Anybody had similar experience? This is a M20J 24V version. I am getting the voltage regulator repaired but like to be sure to test the alternator circuit properly before to turn on the power back. Can also somebody tell me about the little wired diode installed on the brushes between plus and gnd of the alternator Thanks Philip

[PT20J]

Warning light on steadily and tripped breaker means the over voltage relay tripped. Probably a VR problem. Would have been best to do some troubleshooting first. I’d still check all the wiring between VR and alternator. 

Skip

[rgpilot]

That little diode or rectifier is there to ground over voltage when you turn off power. It comes from back EMF created by spinning alternator. If it were not there your circuit breaker would pop.

[ltdoyle]

I had the same problem.  I removed the ground wires and the field wire and cleaned them with a wire brush (they did not look that bad).  I also cleaned the terminals where they attach.  Apparently that solved my problem.

[Philip France 13]

Hello

This is to informyouthat the regulator has been repaired and installed back in the plane everything solved working well Thanks Philip