John Popelish wrote:

Michael A. Terrell wrote:
John Popelish wrote:
RW Salnick wrote:
(snip) You won't need to make any changes to the pulley to
make the
alternator deliver 24 V, but the the diodes and the diode trio will need
to be replaced with 24V versions.
(snip)

Are you seriously suggesting that a 12 volt alternator is
made with a diode trio that cannot handle 24 volts? I was
under the impression that few silicon rectifiers are made
with a breakdown voltage less than 50 volts.


What PIV diodes do you think you need for 24 volts?

Need? 35 volts should be enough to work, but I would like
at least 100 volt.


You are forgetting that when the diode is off, it also has the
battery voltage added to the AC from the alternator, so the bare
minimum would be 24 VDC +(24*1.414=33.936-.6) 33.336, or 57.336 PIV, if
there are no spikes or inductive surges. A load dump can be several
hundred volts, and the diodes have to survive.


What PIV diodes do you think they put in the trio?


The last set I replaced were unmarked. All they had was an OEM part
number. One of the trios opened on the way home from Orlando after
midnight one night. I was laying in wet grass and sand removing the high
output alternator from my stepvan, only to find it was too big to fit my
car. I had to strip both alternators and transplant the diodes to get to
work on time.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida