# What Size Motor Pulley (?)



## mdmade78

I recently found a rebuilt Quincy 325 air compressor and a 5 horse Baldor 184T Frame motor to power it up on an 80 gallon receiver tank. The Quincy has its flywheel, but what size motor pulley should I get for the Baldor? It runs at 1725 rpm . . . Mike in Maryland


----------



## Osviur

*Pulley size*

Hi mdmade78,

Congratulations, it is a really beautiful compressor, I have seen the specs in the manual: http://powerspecialtiespumps.com/images/manuals/Quincy-QR25-Model325.pdf

It is a dual stage compressor, up to 200 PSI continuous duty with a recommended speed from 400 to 900 RPM. If we select an intermediate speed of 750 RPM, we need a motor to compressor speed relation of:

1725 RPM / 750 RPM = 2.3

In accordance with the specs, the compressor pulley is 14" in diameter, so the motor pulley diameter must be : 

14" / 2.3 = 6" 

With this diameter relation (2.3), every 2.3 motor turns, the compressor will make one turn, and in one minute 750 revs.

Enjoy your compressor!


----------



## mdmade78

Thanks for the help Osviur! I'm new to assembling and using my own, decent sized, air compressor. Can I assume that 750 RPM is a good all around speed for general shop usage? Oh, and these days who makes a high quality, twin grooved, motor pulley - Browning?


----------

