Help me troubleshoot electric motor

[JonathanLaporte]

Hi guys.

I have a brunner compressor and now it's starts to act funny.

When I start it it blow the breaker after a few minutes... I can hear the motor slow down and speed up again etc.

Now I'm quite handy with mechanic stuff but need a ha nd with that motor.

On the top if it these some kind of capacitor with lying written on it. I've test it for bad ground and resistance and it shows 28k.

Any idea when the problem comes from? I've check the inside if it and menus a few nick everything is there. It feels like it's missing torque.

Running in 120v.

 

[kbs2244]

Are you sure it is not a failing breaker?

 

[sometoyotaguy]

I'd try a new cap, but it also sounds like the run clutch connections may not be working properly.

There should be a set of contacts that bypass the starting capacitor when it gets up to speed. It will be connected to some sort of centrifugal actuator assembly.

Have some pics?

 

[Davefr]

Have you removed the compressor belt to see if the problem is motor or pump?

 

[Cyberbear]

The reasons for your intermittent motor behavior can be many. It just might be simpler to take the motor to a motor repair shop and have them bench test it, especially if you've done all the usual checks.

 

[Iron-Iceberg]

Ck and see how many amps its drawing with an amp clamp. If it's drawing more than its rated for it could be a problem with the pump.

 

[jontar]

Sounds like the centrifical switch on a dual winding single phase motor

 

[G_P]

Take a look at the capacitor. If its leaking goo or is swollen then its likely the centrifugal switch is stuck and the capacitor is being cooked.

If thats OK, then remove the belt and run the motor with no load on it and see if it still pops the breaker.

But to do any real diagnosis you need to take amperage readings and see if the motor is actually exceeding its rating.

 

[JonathanLaporte]

Ok i've done many test... 1- interal engine has been damaged (Mark on rotor etc.) Also this motor dosn't have bearing... WHAT?!? Its riding right on the shaft! Tried a new capacitor and still the same problem...

Anyway I found a good working 3/4HP engine on kijiji for 20$ I'll give it a try.

 

[JonathanLaporte]

Old motor 8.8amp 3/4hp 1725rpm 115v
new one: 10.8amp 3/4hp 1725rpm 115v

So my engine should have more power right?

 

[Lassen Forge]

For $20 it's worth trying it. A motor shop would probably charge more to fix the old one.

You will have more power only because the old motor is shot! 3/4 HP is 3/4 HP. The amp difference is likely due to different windings in the motor, different type of motor, etc.

Make sure your wiring to the new motor (and your breaker) can handle the extra 2 amps - it would **** (in not a good way) to burn something up because it was overloaded!

 

[JonathanLaporte]

OLD motor: 63 pounds
New one: 33 pounds!


I have a 20amp breaker with the right wire.