Effect of unbalanced supply conditions on the performance of induction machines for aerospace applications

The effects of unbalanced supply conditions on the performance of two aerospace induction machines are examined. Two analytical techniques are employed namely 2D finite element analysis modified for end-effects and a conventional equivalent circuit analysis. In this latter method the supply voltages are resolved using symmetrical components theory into positive and negative sequence sets which are applied to appropriate equivalent circuits. The conclusions reached are that for the sample machines (approximately 4.2 kW and 64 kW), the effects of unbalanced conditions at the general aerospace industry limits are tolerable as far as current balance, torque reduction and heating are concerned. The torque ripple, however, increases significantly, which could be a concern