Induction motors are often braked rapidly by a technique known as plugging, which is the reversal of the phase sequence of the voltage
supplying the motor. Assume that a motor with four poles is operating at 1750 r/min from an in?nite bus (a load-independent voltage supply) at 60 Hz. Two of the stator supply leads are suddenly interchanged.
(a) Find the new slip.
(b) Calculate the new rotor current frequency.