Phase unbalance causes three-phase motors to operate at temperatures that are:

In three-phase motors, phase unbalance refers to a situation where the voltages or currents in the three phases are not equal. This can lead to excessive heating within the motor. When the phases are unbalanced, the motor has to draw more current to maintain its operation, which can increase its overall temperature.

The critical aspect of phase unbalance is that it imposes additional stress on the motor windings and components. The motor experiences increased losses due to higher currents and may not operate efficiently, causing it to run hotter than its designed specifications. Consequently, the motor operates at temperatures that exceed the nameplate ratings, which can lead to reduced insulation life and potential failure if not addressed.

This understanding highlights the potential risks associated with phase unbalance and its detrimental effects on motor performance and longevity.