Current imbalance can occur for a variety of reasons – high-resistance connection, low loading, dissimilar cable sizes, transformer anomalies, winding failures, and voltage imbalance, to name a few. Due to the variety of causes, current imbalance is a good burglar alarm, but further investigation and root cause analysis is necessary to get to the source. One rule of thumb to help when you're troubleshooting a motor with a high current imbalance is that for every 1 percent voltage imbalance you can estimate approximately 7 percent current imbalance.
To learn more about troubleshooting your electric motor using a fault zone analysis approach, go to www.pdma.com/PdMA_mcemax_faultzone.php.