Alternator Issues on 68 337c

lynndsim · #1 10-30-11, 07:08 PM

I recently had to have my rear alternator overhauled and discovered that both front and rear alternators are rated at 28v 30 amps. The Cessna service manual says all 68 and later 337s have 60 amp alternators.
Replacing both alternators with 60 amp alternators would be expensive and I suspect that with my more modern avionics I don't need the increased capacity.
The regulators are original but seem to work fine with these alternators with the exception that I've always had occasional "overvoltage " lights which extinguish when I switch to the other alternator.
Any comments?
Thanks

hharney · #2 10-30-11, 09:40 PM

Do you mean switching to the other Regulator, when you said switching to the other alternator?

I would start by searching the message board for others that have had these type of issues. This thread below is most recent and the member did find the issue. I would not change anything until you check some of these results on this message.

http://www.337skymaster.com/messages...ead.php?t=2966

WebMaster · #3 10-31-11, 06:25 AM

Both alternators feed one voltage regulator. You can switch between the voltage regulator, in case one is bad. Sounds like you have one that is bad. The 60 AMP alternator will place significant loads on the drive shaft. I think most Skymasters have 30-38 Amp alternators.

lynndsim · #4 10-31-11, 05:15 PM

Quote:

Originally Posted by hharney

Do you mean switching to the other Regulator, when you said switching to the other alternator?

I would start by searching the message board for others that have had these type of issues. This thread below is most recent and the member did find the issue. I would not change anything until you check some of these results on this message.

http://www.337skymaster.com/messages...ead.php?t=2966

Thanks for catching it. I did indeed mean switching to the other regulator.
I get the overvoltage light occasionally on either regulator.