32V Alternator Issues

[racclarkson@gmail.com]

I’ve searched the forum on the topic and found lots of useful info, thanks. Still, I have some questions for you electrical gurus.


Starboard 32V alternator was found not charging during last week’s cruise. Charger switched on and battery bank fully recharged. All batteries test good.


I have not yet determined the alternator model/ser. numbers.


Upon further review:

1. Hobbs switch 15A fuse found blown and replaced; 32 volts confirmed at switch. Given its condition on removal, fuse maybe just aged out. Matched readings with port side switch.
2. Alternator 50A fuse good
3. Battery charger 50A fuse good
4. 32 volts found at alternator and cabling found in good shape.
5. Dual drive belts are good and alternator rotation appears normal.
6. Tested at 1,200 RPM and no charging noted. Historically, Stbd unit would excite at under 1,000 RPM.

Does the Hobbs switch do anything re charging other than cutout the battery charger when fuel pressure is read?


I am unsure about what to look for re voltage regulator.


My trusted rebuild shop has shuttered its doors, so I’m doing what I can to eliminate what I can before pulling the alternator off. Thank you in advance for your suggestions.

[Captain Ralph]

On some designs, The Hobbs switch drove a relay, that tied the alternator VR to a close B+ lead.
Just a month ago on this forum, a member was replacing this same relay.

[racclarkson@gmail.com]

On some designs, The Hobbs switch drove a relay, that tied the alternator VR to a close B+ lead.
Just a month ago on this forum, a member was replacing this same relay.

I figured there would have to be a relay to interchange the alternator and the charger. Good place to look. Thanks for the suggestion. I'll look for the posts.

[Briankinley2004]

I cant help you with the technical part but this is the alternator on my 12V71's. I found an off brand replacement online a couple years ago for under $300 and keep it in a box under the stairs to the state rooms. It looks like an identical unit.

http://www.delcoremy.com/find-a-part...etails/1117733

[racclarkson@gmail.com]

I cant help you with the technical part but this is the alternator on my 12V71's. I found an off brand replacement online a couple years ago for under $300 and keep it in a box under the stairs to the state rooms. It looks like an identical unit.http://www.delcoremy.com/find-a-part...etails/1117733

Where are you docked and when will you be away? Off brand meaning Chicom?

[Briankinley2004]

Where are you docked and when will you be away? Off brand meaning Chicom?

Behind the house and during the day. The fuel down here will cost you more than ordering the one below. Its probably Chicom but ships out of Michigan

https://www.motorcityreman.com/7265n.html

[Captain Ralph]

Constantly shopping for a 32v, 30SI has paid off for us. Always a spare and a dust collector till it's needed, then shop for another spare again.
e-bay has worked well for us on this.
Sadly, 50MT starters are another story.

[racclarkson@gmail.com]

Issue put to rest with replacement alternator. It excites around 850 RPM. Thanks Sky for the ebay link.
IMG_2889.jpg
Mr. Hoover, before you point it out, I've got some touchup paint on the way for that bolt head.

[whoover]

Not to worry Mr. Clarckson. I think I have the very same colored bolt head on my alternator adjuster.

Walt Hoover