air compressor will not start / will run as long as contactor is pushed in

by michael
(louisville, ky)

compressor will run as long as contactor is pushed in manually. Replaced with new unit same unit but nothing contactor pulls in but motor will not start. voltage seems to be at all areas. can hear contactor hum but motor will not run.


i reconected the old motor starter so that the compressor will at least run. what is wrong.

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Bill says...

Hello Michael. First dumb question, and I think you have already answered it but I am not sure, is that the pressure in the compressor tank is below cut in levels, right?

When you say "as long as contactor is pushed in manually" I am not certain what this means. Are you saying that the pressure switch has tripped to send power to the motor?

"Replaced with new unit same unit but nothing" means what, please? I don't know what you replaced.

The issue of compressor motor problems comes up m more and more often of late, and often they relate to electrical issues with which I have little experience. So, you are the first on the forum page about compressor motor problems.

Please add a comment with more details. And often, it helps to know the make and HP of the compressor too.

Cheers,

Bill




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Piston Head heats up and Motor Capacitor blows off

by Satish Pathak
(Mumbai, India)

I have small compressor around 1 HP single phase, 45 Liter storage tank. My electrician got the motor rewinding as compressor has stopped working. The motor runs well without connecting shaft to piston. Moment the piston is connected and runs with motor (irrespective of output connected or not connected to pressure tank)the piston head, heat-sink cover starts heating and it further lows capacitor in no time. It happened twice. Pl. advice.
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Satish, from the description of the compressor problem symptoms, I would point to a mechanical failure in the pump, maybe a piston seal gone, resulting in metal-to-metal contact and increased loading on the motor as a result.

That would account for the pump head heating (if it is heating beyond the normal, very hot state when any compressor is running) and increased load on the motor might mean the run capacitor has to work harder, and it overheats.

Cheers,

Bill

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12 Gallon 1 Horsepower air compressor motor wont start

by George Arboleda
(San Jose, CA)

I have an old model Air compressor 12 Gallon 1 Horsepower, my problem is, when you plug the in it's look like the AC outlet it might be shorted it gonna burn my fuse.

If I knock the motor body with the plastic hammer and then it gonna start the motor and when the pressure will reach the maximum set up and then the motor will creat noise and then the power with kick my fuse burn.

Please let me know what issue is this? In my opinion I am thinking that the capacitor is the main problem but I don't know yet where I am going to buy this.

Please I need your help.

Thanks
GMA
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Hi there George... so, when you plug in the air compressor it "looks" like the plug is going to short?

Your compressor symptoms suggest to me that you have a short in the compressor and if this were mine I'd start by checking to see if the pressure switch was operating properly.

That you whack on the motor to get it going also suggest that your compressor motor may have a centrifugal start mechanism that is failing.

Depending on how much time you want to spend on this compressor George, you can pick up a low-cost 1 HP compressor for under $100 dollars these days, and you could either replace the entire power train of your existing compressor with the new one, or, use the existing compressor only as an extra tank, and fill the tanks on both air compressors from the new one.

If you are a tinkerer though, then there will be lots of value to you in trying to figure out what's going on with the older air compressor.

Add a comment here with findings so we all can see how it is going.

Cheers,

Bill


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Induction motor slow..running warm-hot?

by martin
(UK)

so, Ive separated a 2 HP motor and compressor unit from the cylinder and mounted on a bench. Running the motor it runs for a while and then slows as it begins to heat.... If I block the outlet from the pump the motor virtually comes to a stop. Any thoughts? The motor is induction type and 240 volt.
thanks M

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