Newbie compressor info

[macnewbie]

I know the compressor topic has been discussed a million times, but the more I search and read the more confused I am so thought I would just try and ask my question.

I am looking to upgrade my twin stack contractor compressor to a real one that will allow me to do general shop work including some occasional blasting and small paint work (in the future).

I have come across a compressor with the following components.

60 gallon Bell Gossett tank
IR 2340 2-stage pump


I know this setup requires a 5HP motor and I also know the motor needs to be replaced. My research shows that the pump is designed to operate at 1575 RPM. Does that mean the motor will need to operate at 3450RPM? For the experts out there, how do these specs translate to noise level?

Thanks in advance for helping out!

 

[Squankum]

My research shows that the pump is designed to operate at 1575 RPM. Does that mean the motor will need to operate at 3450RPM?

I'm no compressor expert, but this is a belt-driven pump with an electric motor? Sounds to me like you'd need to measure your pulley diameters and do the math to see if they're a 2:1 ratio or what.

 

[EOC_Jason]

Find out if that is the average RPM or the MAX.

Motors usually come in two speeds, 3450 & 1750 RPM. Whichever you get will depend on the pulley size for the motor (assuming you know the flywheel size on the compressor).

Here's some helpful formulas (attaching as a PDF).

 

[scw1991]

That compressor uses a 3450 RPM 5HP motor.

Steve

 

[macnewbie]

Thanks all for the tips. I checked it out today, and it turned out to be an 80 gallon tank, which is more than I need or have space for. The motor on it was 1.5 HP, no wonder it was blown!

At $100, it will still be a great buy for someone who has the space for it.

 

[stonesfan68]

The 2340N5 requires a 3450RPM, 5HP motor. The compressor turns at 1575 RPM and discharges 14 cfm of air at a maximum pressure of 175 PSIG.

I took my machine and put a new pulley on it that turns the pump at 1040 RPM and requires 3HP. The pump and motor will both last for a long time!

At $100 that compressor is a bargin.

 

[AndyA]

The 1.5HP motor may have been ok *if* they had changed pulleys to really slow the compressor down to where it only used 1.5HP. Of course you'll really drop the CFMs by doing this, but the pump should last forever.

I agree with you. They probably threw whatever motor they had laying around and didn't change the pulleys, thus the burnout.

Can you solve some of your space problems if you mount the motor-compressor separately from the tank? Maybe hang the tank to get it up and out of the way (be sure water can still drain). Also not vibrating and stressing the "air bomb" is a good thing.