220v 1ph HVAC compressor amp draw imbalance


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Old 02-10-21, 06:36 AM
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220v 1ph HVAC compressor amp draw imbalance

I have a 220v 1ph compressor that draws 4.8 amps on one leg and 5.6 amps on the other.
What would cause this imbalance?

Am I looking at a compressor failure?

Thanks for any insight.
 
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Old 02-10-21, 07:57 AM
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The current has to go someplace. Where are you measuring current? Did you check to see if there is current on the ground wire? Otherwise, check to see if you have a loose connection.
 
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Old 02-10-21, 12:17 PM
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Thanks for the response.

I am measuring on the compressor side of the start contactor. There is no current on the ground wire. All connections are tight. Voltage is equal on both legs and steady.
 
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Old 02-10-21, 04:12 PM
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There MUST be an even current measurement on both legs. If there isn't either your clamp-on meter is being fooled by a nearby magnetic field or current is flowing to ground. In order to be able check for a leak to ground.... the ground wire must be the only ground to the motor. If it's sitting on a grounded surface.... the ground wire can't be measured.
 
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Old 02-10-21, 04:58 PM
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Thanks for the advice. I am using a Fluke 373 meter. No sources of interference in the immediate area.
I will try and isolate the ground wire and test for voltage.

This unit is still under warranty but the techs are clueless about why this is happening.
I will have them open the motor starter and check it. Now it reads 6.2 amp going into the starter and 5.6 on one leg and 4.8 on the other.

Thanks again for the help.
 
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Old 02-10-21, 05:09 PM
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That is a clamp on meter. It can be affected by the contactor coil.
Try measuring at the source.... the breaker.
 
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Old 02-11-21, 07:46 AM
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Ok, Thanks. I will check it there.
 
 

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