Derive an expression for the instantaneous field current for a three-phase short circuit at the terminals. As in Problem 4, assume that the machine is initially operating with the stator open-circuited and that the speed remains constant during the fault.
Problem 4
Derive an expression for the instantaneous electromagnetic torque during a three phase short circuit at the terminals. Assume the stator terminals of the machine are initially open-circuited and the speed does not change during the fault.