Two days ago I noticed that one of the compressors from this rack was not running. I checked the breaker and found it tripped. After resetting it, the compressor tripped it again when tried to start. Went thru the already learnt procedure of checking winding continuity and terminal to ground check. Nothing unusual. Tried to start the unit for third time, with the same breaker tripping result. Removed the oil pump and was able to turn the crankshaft by hand, so I eliminated the possibility of a mechanical lock-up. My supervisor suggested an oil check. It came out black and smelly: burnout ??? Removed the stator cover and found the winding mostly ok but with just some blackened coils. How is it possible for a stator to be burnout and still give continuity readings between the terminals and no terminal to ground path?
By the way, any suggestion for speeding up the process of removing the old gaskets adhered to the semihermetic metal? The knife scrapping method seems to slow to me?