Abstract

While three-phase AC squirrel-cage motors have been around and reliable since 1889, courtesy of Mikhail Dolivo-Dobrovolsky, one issue that has plagued their operation and lifespan throughout the years has been voltage unbalance. These induction motors are designed to have all three phases of their windings balanced when in operation, ensuring cool operating temperatures and a long service life. However, the introduction of voltage unbalance to these motors is detrimental, with even small percentages creating a recipe for a catastrophic failure if left unchecked.