"Wayne.B" wrote:

They do OK on both counts based on my observations. They're
mounted
on DD6-71 diesels with about a 3 to 1 sheave diameter ratio. They
start producing full output at around 1200 engine RPMs which would
be
3600 alternator RPM.

I would expect a high output alternator to produce about 80% of
nameplate at 2,000 alternator RPM and full output at no more than
3,000 RPM.

Based on your description above doubt they would meet those output
points.

Got any idea of output at 1200-1400 engine RPM?

What is top end of the DD6-71?

Difficult to tell from limited pics on web site, but it appears you
have a small case design, but that is just a guess.

Small case design offers the designer more challenges than larger
cases.

It's mostly a thermal problem.

I have not run any long term stress tests at
high temps but have measured them with an IR gun at about 170F while
producing 200 amps. I've only got about 50 hours on them at this
point so long term durability is still a question mark. At $450 I
can afford to carry around a spare however. They are also
relatively
cheap/easy to rebuild.

$450 seems a bit high, but then I haven't looked at a price for a few
years.

Lew