Yeah, though he did say after a few seconds, so its possible it never got up to enough speed to open the centrifugal switch. If it is a capacitor start - capacitor run motor (pretty common in this size compressor) with both capacitors in parallel until the switch opens either one being bad could cause it. Of course the pump could be seizing and the motor is just fine. More diagnostics are needed.
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Air Compressor Motor Struggling to Run
- Thread starter TomS
- Start date
Also check the security of the wire terminals in the breaker box. The voltage would read correctly without the motor running
but would drop with a load. This is especially true with aluminum wiring. I'm not saying that is the problem but it could be.
It might start and as the poor connection heats up and increases in resistance, the voltage would drop causing the motor to slow down.
Cold temperatures would also cause the motor to draw more current and that would cause a bad connection to be more apparent.
It also could conceivably be a defective(marginal) breaker heating up.........................
but would drop with a load. This is especially true with aluminum wiring. I'm not saying that is the problem but it could be.
It might start and as the poor connection heats up and increases in resistance, the voltage would drop causing the motor to slow down.
Cold temperatures would also cause the motor to draw more current and that would cause a bad connection to be more apparent.
It also could conceivably be a defective(marginal) breaker heating up.........................
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First of all thank you to all of you that chimed in with suggestions. They all were very helpful and informative. Now there's a twist to this saga. Because it was so cold outside this morning (~20 deg F) I decided to wait until this afternoon (~40 deg F) to remove the motor. I flipped the breaker and as I always do I turn on the equipment to make sure I opened the correct breaker. Well as it turned out I opened the wrong breaker and when I turned the compressor switch on it started up and continued to run as it normally does. WTH!? This is good because I really didn't want to buy a compressor motor. So when all else fails you read the instructions, right? I dug through the owner's manual and it says in extreme low temps you can use 10wt non-detergent oil or 10-30 synthetic oil. Got to thinking that the low temps and the 30wt oil was like pumping mud. This is the second winter in my current home and I don't remember having problems like this last year. Whatever! Tomorrow I'll get some 10wt compressor oil or 10-30 synthetic and see how that works out. I'll keep you posted.
+1 to using10-30 Synthetic oil. I went through the same experience in our severely cold environment few years ago, some days the compressor would not even turn or the motor would run very slowly but it all went away when I switched to synthetic oil, there are still some extremely cold days that the motor still labors but I direct the electric heater toward it for 10 minutes and it runs smoothly again.
Sorry for not putting closure to this sooner but a health issue and three days in the hospital kept me out of the shop. So on with it. This morning it's 33 deg F outside and with 10-30 Mobil 1 in the crankcase the compressor started and runs at full speed, by ear. Thankfully it wasn't a motor problem. Thanks again for all the help.