Answer Happy

A three phase, 440 V,50 Hz,4 poles, star-connected slip ring induction motor has an on load speed of 1440rpm. The rated power of the induction motor is rated as 50hp while the miscellaneous losses and mechanical losses are rated at 5.2 kW and 2.6 kW respectively. The parameters for the induction motor are listed as below: Determine: i) The rotor current. ii) The line stator current and the power factor of the three phase induction motor. iii) The rotor copper loss. iv) The starting torque. v) The maximum torque and slip at maximum torque. vi) The overall efficiency of the three-phase induction motor at full load. vii) If the connection of the three-phase induction motor is rewired to delta connection, what would the new line current be? (20 marks)