The star-connected rotor of an induction motor has a standstill impedance of (0.4 + j4) ohm per phase and the rheostat impedance per phase is (6 + j2) ohm. The motor has induced emf of 80V between slip-rings at standstill when connected to its normal supply voltage. Find (a) rotor current at standstill with the rheostat in the circuit (b) when the slip-rings are shor circuited and the motor is running with a slip of 3%

A) Although the magnetic field for each phase of a 3-phase induction motor is merely switching back and forth between north and south poles, the resultant magnetic influence from all phases sets up a rotating magnetic field to cut the rotor conductors. a) true b) false B) In a two-pole stator winding of a 3-phase motor, how many revolutions does the rotating tr) magnetic field make in one cycle of the electrical current? a) one b) 60   c) 3600 d) none of the above

Draw the per-phase equivalent circuit of a three-phase squirrel-cage induction machine. List all of the elements in the equivalent circuit and briefly state their function

In a three-phase induction motor the maximum torque occurs at 20% slip and the equivalent resistance of the secondary is 0.04Ω per phase. Find the equivalent load resistance and the load voltage and the load current. Output power is 20 kW.