Braking and pulsating torques of induction motors with voltage control due to semiconductor failure

Contents The calculation of unsymmetric a.c. and d.c. currents, pulsating and braking torques in asynchronous three-phase machines caused by a semiconductor failure is presented by symmetrical components. Neglecting the stator resistance a simple solution is obtained describing the worst case. The exact calculation requires the analysis of the switching conditions of the semiconductor. While starting, pulsating and braking torques arise to a multiple of the rated torque. By means of experimental investigations on a 11 kW motor the analytical-numerical method is verified.