Converter-fed induction motor losses in different operating points

The use of converters to feed the motors instead of the direct-on-line supply has increased the need to understand the losses of the induction machine in different operating points. Most of the earlier studies have focused on the losses with the nominal supply frequency while this study covers most of the frequency-torque plane below nominal values. A 15 kW standard squirrel-cage machine's losses are analyzed in 16 different operating points with torque values of 25 %, 50 %, 75 % and 100 % of motor rated torque and supply frequency values of 25 %, 50 %, 75 % and 100 % of rated motor frequency. Measurements in all 16 operating points are made with both sinusoidal generator supply and with frequency converter supply.