LEC fridge compressor not starting

[ftgpmb]

I have a 5 year old LEC fridge with Danfoss compressor which just hums and gets hot to touch - doesn't sound like it is turning over. Compressor windings measure 44 ohms and 38 ohms and no measurable short. Capacitor is specified as 4 uF but when measured reads 1.5 uF. Hope it isn't the compressor.... wondered if the capacitor could be the cause of the compressor behaviour? worth replacing capacitor and start relay just to see?

 

[Leccy758]

Capacitor has gone low in value, can not kick the compressor motor into life. with luck it should be ok with a new capacitor

There are usually 3 terminals on the compressor with 2 windings (start and run)

A-B should equal X ohms
A-C should equal Y ohms

B-C should equal X+Y ohms

Markings and values vary between some compressor motors.

 

[ftgpmb]

Thanks. Let's hope so! I have a new capacitor on order.

Motor winding resistance measurement check out as per your formulae. I've also read somewhere that the starter winding has a higher resistance than the run winding... which mine does.

I took the relay off and powered up the unit. I got 220V on both start and run poles of the relay. Not sure what would happen under load though. I've ordered a replacement relay as well just in case.

I'll report back when it all arrives.

 

[ftgpmb]

No way! didn't work. even tried "jumping" the compressor. No joy, just the dreaded humm. anyone want a perfectly good 4 uF capacitor?!
Guess I'll be looking for a new fridge.