Air Compressor Issues

[Unbreakable]

I have a 60 gallon Industrial Air compressor (about 35 years old) that would not get up to full speed and kept tripping the breaker so I replaced the capacitors, this did not help although one was definitely bad, so I replaced the motor thinking this would fix it, but did not. It starts and the centrifugal switch clicks back and forth until I unplug it. I remove the belt and it seems to run just fine, put the belt back on and disconnect the air line from the compressor to the tank and it runs fine, so I replaced the check valve and line (larger diameter) and this didn’t help. I then disconnected the unloader line and this did not help either.

I have checked the capacitors on the new motor and one appears to be bad, so I am waiting on a replacement but I was also thinking about the diameter of the pulleys, the motor is 5 3/4 and the compressor is 14 1/2, aren’t these OK? I think the motor should be around half the diameter of the compressor. The compressor turns easily, any thoughts would be appreciated.

 

[Shoreline_]

It ran fine this whole time, why mess with the pulleys? The belt is tight? 2 stage or single stage? Someone plug the interstage relief valve?

 

[Jswain]

STOP replacing parts and start troubleshooting

Do you have good voltage at the breaker & receptacle, is the plug replaceable? Have you checked the connections? Check for proper voltage at the pressure switch?

How many amps is the old & new motor? Pics of the tags?

Not running it on an extension cord?

You could maybe change your name to Unfixable

 

[vavet]

Try an outlet on a different circuit. Circuit breakers can wear out. If it’s close to the max amperage, it might be more likely to trip. I had this exact problem several years ago and finally figured out it was the CB.

 

[MacMcMacmac]

Same motor rpm?