"Ignoramus6689" wrote in message
.. .
On Tue, 09 Aug 2005 15:51:56 GMT, RoyJ wrote:
Oops, I thought the original motor was 3hp. Do verify that both 3 phase
and single are the same speeds, a lot of older 3 phase are 1750, smaller
single phase tend to be 3450 rpm.

I believe, but not 100% sure, that both motors are 1750 rpm or there
about. I hope that they have the same frame. The old 2 HP has a 145T
frame.

Smaller pulley on the motor cuts down the required starting torque,
runpower requirements, lets it run cooler and quieter. Cuts down the
air output as well.

I figure, if I replace a 2 HP motor with a 2 HP motor, I can as well
keep the pulley if the shafts match. A marginally better life
expectancy does not matter too much on a relatively cheap used
compressor. Now, if the shafts do not match, I will buy a slightly
smaller pulley from McMaster.

i

I

I'd advise you to save your money and not change the pulley. The start
up torque is always low with a properly adjusted compressor. The pulley/HP
ratio can be compensated for by setting the cut off pressure lower. Your
mileage will vary.

Jerry