Re: P.M. alternator

Posted by DavidPackard On 2017/4/26 19:19:21

Howard

I called CAS today. They disavowed any knowledge about the AC system in my (Bill Lauer's) '54. Their comment was they do not install or work on AC systems, so although I'm never wrong this time I was a little short of being right. I found the stack of receipts that came with the car when I bought it, and there was a single page, not quite a receipt, but a single page with no letterhead, that detailed some of the parts and cost associated with the AC installation. On that page was mention of an automotive refrigeration business in Orange, CA. I'll call them tomorrow and post the details of that conversation. Perhaps that company configured units to the desired voltage and polarity . . . one can only hope.

I have some amount of experience with PMs, they been used on motorcycles for years. I see only two wires in the photos you posted. My bet is that is the AC output of the alternator, with all of the rectification and voltage limiting provided by the 'regulator'. That's the good news is, you can configure whatever you want. The PMs in a Harley produce at least about 12 volts per 1000 rpm . . . that's the AC voltage. So at full song the AC voltage is north of 70 volts. The regulator is heavily finned and faces the wind. I suspect if I cut one apart I would see a rather large Zener along with a diode based bridge.

dp