Practical methods to resolve voltage quality problems with AN induction motors

The voltage nameplate ratings found on many AC motors and drives have been a source of confusion for utilities, and their customers. Specifically, the confusion stems from the range in voltage that a particular motor may be operated from safely. Additionally, voltage unbalance is known to create premature failure of heavily loaded motors if they are not properly derated. This paper discusses the standards associated with AC induction motors and their nameplates and details the voltage quality issues that may warrant a problem solving investigation. Additionally, the paper describes a systematic method for conducting a motor voltage quality investigation and discusses several remedial actions when voltage at the motor terminals is either too high, too low or is unbalanced.