Compressor failure

[gilbert_c]

Can someone please tell me what the normal ohm readings should be on a 5 ton 3ph compressor, and what a typical failure reading would be? It's a Bristol/York unit. Unit has a tandum set and one single compressor. It's the single one I'm concerned with. My problem is, I just don't remember what the readings should be. You guessed it, I'm a novice. Thanks,
gil

[Peter_1]

You don't need the exact readings: all 3 windings should be the same in the order of some ohms and there may be no connection to the ground measured with a megger.

[NoNickName]

Well, a megger for a novice would sound more like a Megaohmmeter, a funny device that is useful for creating voltaic arcs and toast colleagues... not that I know anything about... stories told in the workshop

[Peter_1]

It's the only device to measure earth faults.

[Renato RR]

It's the only device to measure earth faults.

If you have only ohmeter you can measure betwen each winding and housing of compressor.If you have readings in mega ohm or break reading everiting is ok.But if you have couple houndread of ohms then the winding of the compressor have conection with compressor housing (replace compressor).

Renato

[NoNickName]

It's the only device to measure earth faults.

Yeah I know. Have you tried to measure the body resistance of any of your colleagues with a megaohmmeter?

[gilbert_c]

If you have only ohmeter you can measure betwen each winding and housing of compressor.If you have readings in mega ohm or break reading everiting is ok.But if you have couple houndread of ohms then the winding of the compressor have conection with compressor housing (replace compressor).

Renato

Thank you Renato.
Gil

[knkreb]

Gil, each compressor has it's own motor, and they all have different ohm readings for each motor. There really isn't a set "standard" ohm reading for a given horsepower compressor. Just take a look inside of Copeland's Electrical Manual, and you will see different ohm values for many, many different compressors.

Bristol could offer you the exact ohm readings if you really need them.

Question is, are you having a problem with the system that you are attempting to rectify? And what is the problem?

[sunilbhat]

Can someone please tell me what the normal ohm readings should be on a 5 ton 3ph compressor, and what a typical failure reading would be? It's a Bristol/York unit. Unit has a tandum set and one single compressor. It's the single one I'm concerned with. My problem is, I just don't remember what the readings should be. You guessed it, I'm a novice. Thanks,
gil

it should be about 3 ohms eqally all three terminals


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