3P Induction Motors

A three-phase motor is rated 50 HP, 440 volts and 85% power factor. What is the rated current if the motor efficiency is 89%?

What is the speed of an induction motor of four poles if the percent slip is 3%?

Find the rotor frequency of an induction motor having 4 poles if the rotor speed is 1,746 rpm.

A 3 phase, 60 Hz, 6-pole induction motor delivers 25 HP at 1,150 rpm. If the rotor copper loss is 300 watts, what is the rotor power input?

A six-pole induction motor is connected to a 60 Hz supply and at full load the rotor emf makes 105 complete cycles in 2 minutes. Find the rotor speed.

A 12-pole, 3- phase alternator driven at a speed of 500 rpm supplies power to an 8-pole, 3-phase induction motor. If the slip of the motor at full-load is 3%, calculate the full-load speed of the motor.

If the stator voltage of a SCIM is reduced to 80% of its rated value, the torque developed is reduced by ____ percent of its full-load value.

A three-phase, 4-pole, 50 Hz induction motor supplies a useful torque of 160 N·m at 4% slip. If friction and windage losses are 500 watts, determine the rotor input.

A three-phase induction motor has a nameplate speed of 1,720 rpm. What is the rotor frequency?

A 6-pole, 50 Hz, three-phase induction motor has a maximum torque of 200 N·m when it is running at a speed of 900 rpm. The resistance of the rotor is 0.25 Ω. Neglecting stator impedance, determine the torque at 5% slip.

A 4-pole, three-phase 50 Hz induction motor develops a maximum torque of 20 N-m at 1,440 rpm. Obtain the torque exerted by the motor at 5% slip.

The frequency of the emf in the stator of a 4-pole induction motor is 60 Hz, and that in the rotor is 2 Hz. At what speed is the motor running?

How much larger is the rotor reactance of a SCIM at start-up than it is when the motor operates at 5 percent slip?

Wye-delta starting is equivalent to autotransformer starting with __________ tapping.

A three-phase, 4-pole, 60 Hz induction motor has a rotor resistance of 0.02 Ω/phase and a standstill reactance of 0.5 Ω/phase. Calculate the speed at which the maximum torque is developed.

A three-phase motor is rated 50 HP, 440 volts and 85% power factor. What is its rated current?

A 3Φ, 6-pole, 50 Hz induction motor develops 3.73 kW at 960 rpm. What will be the stator input if the stator loss is 200 watts?

A three-phase induction motor is taking 40 kW, the slip being 4%, and stator losses amount to 800 watts. Calculate the total power developed.

An induction motor with 8 poles, 60 Hz is operated with a slip of 3%. Calculate the rotor speed.

What is the speed of a 60 Hz induction motor of six poles if the percent slip is 2.5%?