On Sun, 05 Jul 2009 10:12:13 -0500, RoyJ
wrote:

A friend came by with a non functioning olde 1 hp motor the other day. A
quick check showed no starting circuit (bad cap or bad centrifugal
switch). Pulled the old cap out, it is the old style aluminum case, NO
MARKINGS.

So what size cap to put in?? I just picked a ~200mfd and called it good
but I don't think that is the right answer. So what/how is the cap
sized? Too small a cap and it won't do anything useful. But is bigger
better? Or is the cap matched to the motor in a resonant circuit?

Motor in question is a Westinghouse 1hp 120/240 motor. Judging from the
grease caps, case style, paint color, etc, I'd guess 1940's, maybe early
50's.

If you can read the nameplate, look closely - normally there's a
call-out for size and voltage ratings.

And if not, call Westinghouse with the model and serial number and
ask - sometimes they still have the old records available.

There's a LOT of old equipment out there still in daily service, and
sometimes people decide to rebuild rather than replace. And sometimes
you can't GET a new replacement without spending megabucks on
something custom, so you have to rebuild the old one.

-- Bruce --