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Q2. (a) For a three-phase squirrel-cage induction motor (SCIM): (1) Brief the principle to produce a rotating magnetic field by applying polyphaser currents on the stator windings. (ii) Explain how the torque is induced on the rotor due to the rotating magnetic field produced by the stator windings. (10 marks) (b) A 3-phase star-connected 380 volts (line-to-line) 20 kW, 60 Hz, 6-pole induction motor has the following equivalent circuit constants in ohms per phase referred to the stator: R1 = 0.3, R2 = 0.15, X1 = 0.5, X2 = 0.2, Xm = 60 The total friction, windage, and core losses may be assumed to be constant at 450 watts, independent of load For a slip of 2 percent, compute the stator current, power factor, rotor speed, air gap power, internal mechanical power, output torque and mechanical power, and the motor efficiency when the motor is operated at rated voltage and frequency. (15 marks)