When an engine’s compressor experiences a voltage imbalance between the motor terminals, it can cause the compressor to overheat. To determine the magnitude of the imbalance, you need to measure the difference between each phase’s voltage and average voltage.
When an imbalance exists in a three-phase motor, the largest imbalance will be divided by average volts to calculate a percentage. This percentage will then be multiplied by two to determine an increase in winding temperature. In other words, a small voltage imbalance can lead to a large increase in winding temperature and potential compressor failure. Therefore, plant personnel needs to be aware of this issue when examining compressors.
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