SOT Regarding Air Compressor

[justinevert]

In my fortress of manhood known as the mancave where Lola sleeps, the motor to my 60 gal. V-Twin compressor has siezed. Looking around for a replacement I see the rpm on new 5 hp single phase 220v 20 amp motors to run either 1,750 or 3,400. Which one is the proper speed?

The motor plate on the old is missing and I am at a loss to which one to choose. Would someone be able to help?

Thanks in advance!!

Justin

[Guest Anonymous]

does you compressor pump have a plate with rpm? You could figure it out from the pulleys then. You might be able to figure it out just by looking at the size of the pulleys and deducing the rpm difference between the two.

[justinevert]

All I can find is the cfm to psi ratio, nothing regarding rpm.

Justin

[Guest Anonymous]

I don't know alot about motor construction but a quick search revealed that if you know the poles, the rpm is easy to calculate. I couldn't tell you definitively what to look for in the motor. Do a little searching and I bet you could figure it out.

http://www.elec-toolbox.com/Formulas/Motor/mtrform.htm

[Beaner7102]

Please excuse my ignorance, but as the pump is belt driven it really would not matter. The 3400rpm motor will have double the CFM output to that of the 1750rpm one - you can never have too much air.

Beaner7102

[Guest Anonymous]

The root of why you can't just double the rpm not work is that the motor must have the torque to be able to turn the load (and the compressor pump must be able to handle the rpm too). In electric motors, low torque motors turn at a higher rpm and through gearing (pulleys) you wind up at the same hp and rpm at the pump.