Air compressor motor repair help

[67King]

Accidentally left on the air compressor the other day. It blew the circuit breaker at some point. Go to turn it on, and I get sparks, but no life, and it kills the circuit breaker. Disconnected teh belt, it turns fine by hand, but same thign happens when I send power to it. Have about 6 Ohms across the leads.

End up taking the thing apart and I see nothing obviously wrong. Other than a lot of dust from wearing through a belt a while back. Unfortunately I need air to blow out that, but I don't have that....

At any rate, I don't see any brushes on the thing, I'm guessing it is some sort of brushless device. I odn't know much about electric motors. The only other failure I had with one was a start capacitor that went bad, but that one didn't trip the breaker or spark, it just sat still and hummed. THis one sparks and trips the breaker.

Two questions - one, anyone have any idea what it may be? Second, I wouldn't mind just taking the &*^% thing somewhere and letting them fix it, as I've got a pretty full plate now. But I have no idea how to even find a local business that actually does electric motor repair. Most of the searches are coming up with car repair places or a couple of hugy industry places. Anyone have any suggestions on I actually find a place?

Motor is a 5.2 horsepower, single phase, 220V, 22Amp motor.

 

[justsam]

I can't help but think that Knoxville has some electric motor repair places. Look in the "industrial area" of town. The issue may be cost of repair versus cost to replace. Is this a high quality, ball bearing motor or some "Econo" over rated motor? Who is the manufacturer? Can you send a picture of motor data plate in eluding duty rating?

Internal arcing may be an issue with start/run contacts, or some windings that are shorted or hitting the case. Was the motor ran for an extended period with a heavy load on it? Does the compressor have an unloader? What controls the motor, only the pressure switch, or is there a contactor used?

Bottom line, take it to a reputable shop, and they can advise repair or replace.

 

[67King]

It is a Century, about 12 years old, made in Mexico. Ball bearings on both ends. eReplacement parts has one for $325, Amazon at $250. So I'd assume it is pretty decent. It hasn't run unloaded, it was turning the 2-stage compressor. Well, unless something blew off that I don't know about in which case it would be just moving air, so not totally unloaded, but not like it would be kicking on at 125PSI.

I assume there's a place here, too. Just don't know why I can't seem to find one doing a search that comes up.

 

[wyliesdiesels]

Where are the sparks coming from?

 

[67King]

Where are the sparks coming from?

Hard to tell exactly. Where the power comes in, there is a piece where the wires are connected for the power feed, and then they go back there to the windings. Appears to be from behind that piece, but I can't tell exactly. You know, the more I think about this, the more I'm wondering if it is just arcing from buildup of belt wear and a couple of belt failures* over the years. The cooling fan is positioned such that it would pull in any bits of belt that come off from abrasion.

* I had a lot of trouble keeping the motor positioned. It would loosen enough to let some slack in the belt, and when that happened, it would slip at the motor's pulley. Wore through completely one time, but I caught it several others. Still, over the years, a lot of belt dust accumulated.

 

[wyliesdiesels]

take it to a shop and have them blow it out

 

[67King]

Alright, found a place. Called a starter and alternator shop, and they referred me to a place. Will try blowing it out first, though.

 

[wyliesdiesels]

Does this motor have a motor starter or integral overload protection?

 

[67King]

Does this motor have a motor starter or integral overload protection?

Not sure what a motor starter is? Maybe a pair of I believe inductors? There are some mounted on top of the case, and are away from the area where it is sparking. It does have the overload protection, but that has not tripped, just the main breaker. That whole system is mounted on top of the case.

 

[Norcal]

Post some pictures that way people can see what is there and be able to help you better.

 

[justsam]

The two bulges on top of the motor are start and run capacitors. If the motor has it's own overload, most likely no contactor or other motor start involved. Motor is controlled directly from contacts on pressure switch, a two inch cube with some plumbing and wiring to it. Who made the entire com[ressor unit?

 

[Aceman]

Take the cover off the motors j-box. Give it the smell test.

If it doesn't pass the smell test, throw the motor away. We deal with a very knowledgable motor shop and the good old boy who has worked there since probably before I was born, tells me anything less than 10HP is disposable.

 

[Norcal]

Take the cover off the motors j-box. Give it the smell test.

If it doesn't pass the smell test, throw the motor away. We deal with a very knowledgable motor shop and the good old boy who has worked there since probably before I was born, tells me anything less than 10HP is disposable.

The only thing that could change things about the above post is if the motor was a special purpose one that was hard or impossible to replace. A compressor motor does not fit that discription.

 

[67King]

Windings were shot. So it is junk. I guess teh replacement is typically $475, but I found one on Amazon for $250. Exact same one, fortunatley, so mounting will be easy.

 

[wanderer]

I was going to say that it sounded like a winding problem. When it hums like that it's usually a bad start capacitor. You can test this by spinning the motor by hand(with a rope) and then turning it on. If it powers up and runs you have a problem with the start cap or the centrifugal switch.

 

[1953mercury]

When you replace your motor you might want to include a positive horizontal screw (2ea.) adjustment to your motor base. You can either build your own or source from Grainger or similar. This would eliminate a lot of future grief with belt alignment and slippage. Mike