01․ A 4 pole 50 Hz 1-phase induction motor is running at 1470 rpm. Find the forward and backward slips?
02․ If we increase the rotor reactance value, the maximum torque will
Therefore, if we increase the rotor reactance value, then maximum torque will decrease.
03․ From no load to full load the slip will
Under no load condition the motor speed is Ns i.e., Nr = Ns. As load increases the speed will decrease. Therefore the slip will increase slightly. Practically slip varies from 1% to 4% from no load to full load.
04․ A 440 V, 3-phase, 10 pole and 50 HZ synchronous motor delivering a torque of 50 N-m, delivers a power of
05․ A 3-phase, 50 Hz, 4 pole induction motor is running at 1440 rpm and rotor input power is 2KW. Find the rotor copper loss?
06․ A 3-phase, 50Hz, 4 pole induction motor is running at 1440 rpm and rotor input power is 2KW. Find the rotor output power?
07․ A 3-phase, 50 Hz, 4 pole induction motor is running at 1440 rpm. Find the rotor efficiency?
08․ Torque developed in the rotor is
09․ A smaller air gap in a induction motor helps to
Air gap sends the power from stator to rotor. If the air gap between stator and rotor is more, stator will draw more magnetizing current from the supply in order to establish the rotating magnetic field in the air gap between the stator and rotor. As the airgap offers high reluctance and low permeability to the flux required by the rotor, it requires more magnetizing current. To avoid this condition, smaller air gaps are used in between stator and rotor.
10․ No load test on induction motor is conducted to find which of the following losses?
In no load test the motor runs freely on no-load by applying rated voltage across its stator and no load power consumption is measured by two watt-meter method. No load power consumption is nothing but no-load losses, which are stator core loss, stator copper loss due to no load current and rotational losses.