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Thread: Compressor Windings
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08-07-2020, 10:48 AM #1
Compressor Windings
I have a 22 kW Mitsubishi Electric condensing unit with a 10HP Mitsubishi compressor that comes up with U6 error code. A U6 error code is over current.
The compressor is a 3 phase compressor with a maximum running current of 22 Amps.
I test the compressor for the following:
Phase to phase resistance of all windings is 17 Ohms
Insulation resistance of all windings is 0 Megohms.
The compressor runs for about 1.0 to 1.5 seconds then comes up with the U6 error code.
Does any one know what the compressor winding should be for a Mitsubishi Electric compressor model # JH521YEB?
I have been told around the 1.0 Ohm or so.
If the compressor windings have increased in resistance, how is this so?
After talking to Mitsubishi I have found that a U6 error occurs from one of 2 inputs:
The thermal overload NC contacts or the compressor thermostat, NC contacts which are in series.
I have disconnected both of these and bridged the CN23 pins on the outdoor circuit board and the outdoor unit comes up with a H7 code then trips the circuit breaker when started.
I have tested the contactor - Perfect
I have tested the the thermal overload - Perfect
I plugged in CN23 connector after this test and I get H2 & H6 code.
As the compressor is not down to earth or not jammed, can anyone of you giys come up with what is going on?
This one is a first for me, 40 years of doing this!
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08-07-2020, 12:19 PM #2
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08-07-2020, 08:20 PM #3
Re: Compressor Windings
Sorry, I wrote that down wrong, resistance is high, no leakage to earth
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09-07-2020, 11:31 AM #4
Re: Compressor Windings
If you disconnect the compressor from the circuit does the unit still trip on overcurrent?
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10-07-2020, 11:30 PM #5
Re: Compressor Windings
No,
As I said, the windings are not down to earth using a megger at 1000V and resistance between all three windings is 17 ohms.