Compressor motor pulley sizing

by al
(syracuse ny)

Sanborn V twin compressor

Sanborn V twin compressor

Fantastic Site!

Question. All else the same, which is better:
A 2 inch motor pulley and make 125 psi slower, or a 3 inch motor pulley and 100 psi faster.

So, I'm limited to 120 volt at my place.
I have a Sanborn V twin compressor which is 110/220 set at 110. hp is 2, Amps are 21 on 110. Motor is 3750 rpm. Am on a 15 amp circuit.

Stock, it came with a 70/100 psi cut in/out.
I bumped it up for more air, and found that above 110 psi, it would blow the breaker because its drawing more amps.

I had a wild idea, and decreased the motor pulley size to 2 inches instead of three. Now, I can pump to 125 psi and no breaker blowing! Obviously takes more time, but the pump is noticeably cooler.

I'm certainly at the limits of the unit. But! here is my question.

For running impacts, a little painting, and blowing out sprinklers, which is better. Having the compressor run slower up to 125 psi with a 2 inch motor pulley, or having the compressor run up to 100 PSI with a 3 inch pulley?

Comments for Compressor motor pulley sizing

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Sep 07, 2016
speed or pressure
by: Doug in

It depends on how you use your tools.

Most tools run fine at 90 psi, so the issue is do you tend to use them in short bursts, or a little longer?

The higher pressure will stay at 90 longer, but as you know will take longer to build.

It's very nearly the same amount of air either way.

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