Opener hums/motor or capacitor?

[checkin]

With the chain disengaged, gears are good condition, I can turn shaft via the cup on the end, plug it back in, will start to move, stop, then hum.
Pushing the on again, just hum, which seems like bad brushes in the motor.
The capacitor looks ok, with an ohmmeter, the ground & continuity are normal.
Any way to check the motor?
(Sears 1/2 hp 139.53310)

 

[pattenp]

So how did you test with ohm meter to think cap is OK? Does your meter have a cap test setting?

 

[LS6 Tommy]

It hums because...



It doesn't know the words.


What brand? Could be a bad capacitor, a bad start switch, a bad winding... I doubt it has brushes unless it's a newer DC style unit. Even then it may not. Usually only the low buck DC units do.

Tommy

 

[upndown]

You're still messin with that same opener?

 

[MovingAlong]

Run capacitor. They're cheap off Amazon...

From Wikipedia "Some single-phase AC electric motors require a "run capacitor" to energize the second-phase winding (auxiliary coil) to create a rotating magnetic field while the motor is running.[3]"

If your motor is starting briefly, but then not going anywhere, it sounds like you have a dead spot in the windings - which you would if the run cap was bad.

I've found caps to be the problem on many motors and typically start there.