-Phase 50Hz 6 pole induction motor has rotor resistance of 0.1 ohm and reactance of 0.92. ignore voltage drop in stator and assume thee rotor resistance is constant. Full load slip is 3%, then find Tmax /Tfl

The supply frequency to the stator of an 8-pole induction motor is 50 Hz, and the rotor frequency is 3 Hz. Determine the slip and the rotor speed.

A 3-0, 50-Hz induction motor with its rotor star-connected gives 500 V (r.m.s.) at standstill between slip-rings on open circuit. Calculate the current and power factor in each phase of the rotor windings at standstill when joined to a star-connected circuit, each limb of which has a resistance of 10 Q and an inductance of 0.03 H. The resistance per phase of the rotor windings is 0.2 Q and inductance 0.03 H. Calculate also the current and power factor in each rotor phase when the rings are short- circuited and the motor is running with a slip of 4 per cent. [13.6 A, 0.48; 27.0 A, 0.47] (London University) A 4-pole, 50-Hz, 3-phase induction motor has a slip-ring rotor with a resistance and standstill reactance of 0.04 2 and 0.2 2 per phase respectively. Find the amount of resistance to be inserted in each rotor phase to obtain full-load torque at starting. What will be the approximate power factor in the rotor at this instant ? The slip at full-load is 3 per cent. [0.084 2, 0.516 p.f.]…

A 3-phase 4-pole, 50-Hz induction motor runs at a speed of 1440 r.p.m. The rotating field produced by the rotor rotates at a speed of ..... r.p.m. with respect to the rotor a) 1500 b) 1440 c) 60 d) 0