Alternator on 8v71N is real hot to the touch engine off

[captwoodyb]

Hi Everyone, Just finished up a family run on the 4th of July and noticed this morning the engine alternator on the starboard engine is real hot to the touch after engine off for 8-10 hours. Large battery charger in port engine room charging and also a little hot but not as bad as the alternator. Any one suspect whats going on ? i shut down all the 32volt equipment with the exception of the bilge pumps until I can get back down to try and figure it out. Any suggestions, experience with this ??? Thanks Captwoodyb

 

[Pascal]

problem in the alternator... disconnect the main lead asap.

i had a similar issue on a new self exciting 32v alternator i installed on one of my engines 3 years ago... forgot the specific but power was flowing back in the alternator causing it to get hot... but not blister hot !

 

[Trojan]

It sounds like the exciter voltage is not being turned off. Take a look at the regulator connections with a volt meter. Maybe a shorted voltage regulator. Key off there should be no exciter voltage. Try disconnecting the regulator and see if the charger drops off. If the regulator is internal lift the battery feed wire from the alternator and watch the charger.

BILL

 

[TedZ]

The alternator is being "motored" by a bad voltage regulator. Batteries would die but charger working hard to keep them up.

Disconnect batteries. replace regulator ASAP.

This is just a variation of what Bill said. He has it figured out.

Ted