Energetic behavior of induction motors fed by inverter supply

A complete analysis of induction-motor losses increasing due to the inverter supply is made. The study is based on the analysis of no-load and short-circuit tests performed with sinusoidal, square wave, and PWM (pulse width modulated) inverter supplies. For the PWM supply the effects of the modulation index on the iron losses are considered. Comparisons of experimental results are made to analyze the motors' energetic behavior. To verify the limits of the no-load and the short-circuit tests in the analysis of the loss increases due to inverter supply, a complete set of load tests have been performed using a test bench equipped with speed and torque transducers