A 6-pole, 60-Hz, Y-connected, three-phase induction motor develops a torque (Td) of 250 N.m at a speed of 720 rpm. The rotor resistance is 0.4 Ohm/phase, and the stator winding impedance is negligible. A) What is the air-gap power? B) What is the rotor current refered to the stator? C) If the rotational loss is 1kW, what is the motor output power in hp?

A 240 V series motor develops a torque of 120 Nm at a speed of 900 rpm. The armature winding resistance is 0.20 and the series field winding resistance is 0.1 Q. For a constant load torque find the new speed of the motor when a diverter resistance of 0.1 Q is placed across the series field winding.

(Qld) A three-phase 20-pole induction motor is rated at 800 V, 50 Hz. What is the synchronous speed of this machine if the voltage at its terminals is reduced to 400 V (a) 150 rpm, (b) 300 rpm, (c) 600 rpm, (d) 3000 rpm

3. A 440V 60-hp six pole 60 hz A connected induction motor has the following parameters R1=0.048 R2= 0.035 Xm= 9.50 X1= 0.33 0 X2= 0.37 0 Pcore= 600W PF&W= 350W Use the Thevenin's Equivalent circuit concept to find: (a)Vth and Zth seen by the rotor circuit (b)The slip at which maximum torque occurs (c) the value of Max/pullout Torques (d) The starting torque.