Iron Horse Air Compressor barely turns - stops at 30 PSI

by Matt Cantrell
(Fayetteville, NC)

Helllo,

I have a Iron Force 7.0hp, 60 gallon, model number vt6329.

This compressor is for my home shop and has been around for about 4 or 5 years. However, during those years there has been VERY little use. I have been deployed and so my shop tools have not been used frequently.

Today I wired it to begin use with my sandblaster (230vac) and it barely turned over. Just kind of churned till about 30psi and then stopped. Motor is making a sound like it is trying to turn but can not.

I do not want to keep attempting to get it going because I am afraid I will burn up the motor (btw, the motor is a 2 cylinder, 100% duty cycle, 15amp 60hz).

When I shut it off after about 3 minutes of it churning the motor felt warm, warmer then I would expect it to be in such a short run with the outside temps being in the high 50's.

I have read about the check valves and bad gaskets, but my tank has no leaks. I unplugged it a hour ago and it is still at 30psi.

I also checked the voltage at the tank and I have 129vac on one phase and 109vac on the other phase.

What should my next move be to diagnose my failing compressor?

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Bill says...

Hey Matt, welcome back from your deployment! Home safe is very good.

This puzzles me a bit... "I also checked the voltage at the tank and I have 129vac on one phase and 109vac on the other phase." Do you mean that you checked the voltage at the pressure switch? I'm not an electrical guy, so I call on my electrically oriented visitors to tell me if this voltage is OK. Sounds like it, but I'm not sure.

The obvious question, and one I am not qualified to answer, is, are you sure the wiring is right?

When your compressor stops at 30 PSI, do you mean that the pressure switch trips, or the motor grinds to a halt?

How long does it take to get up to the 30 PSI, and, silly question as you seem to be pretty savvy, but how is the oil level... good?

The compressor motor will lug if it is failing, or quite often, because the load it's driving is increasing to the point where the motor cannot overcome the load, and stops. A breaker or fuse will normally pop at this point, and if that doesn't happen, then yes, you can fry the motor.

De-couple the motor from the drive and see if it starts and runs OK without load.

Add a comment to this thread and let us know what's happening, OK?

Cheers,

Bill