Voltage and impedance conditions for the rapid plugging of induction motors including Saturistor control

It is shown that the accelerating or braking time of a polyphase induction motor after a step change of applied voltage can be estimated by using the reciprocal-accelerating-torque/speed curve. For some transitions, the time required is shown to vary inversely with the area under the steady-state-torque/speed curve. Balanced applied voltages are shown to be preferable to unbalanced voltages for plugging purposes. Equations developed for speed-response times include load-torque terms. The use of Saturistors is shown to be advantageous in giving low speed-response times without excessive motor currents.