01․ For larger units high torque it is preferred to use

For larger units high torque squirrel cage induction motor, slip ring induction motor are preferred.

02․ Belt conveyors offer _______________ starting torque.

Belt conveyors require high starting torque. Hence for belt conveyors slip ring IM will employ.

03․ The application that need frequent starting and stopping is

Lifts and hoists are requires frequent starting and stopping because load is not constant.

04․ Fifth harmonic component of the induced voltage in three phase AC generator can be eliminated by using a winding pitch of

Coil span factor n

^{th}harmonic, K_{c}= cos( 0.5 X n X θ). Where θ is an angle by which the coil is short of the full pitch. Those fifth harmonic component gets eliminated by using a coil pitch of ( 4 / 5 ).05․ In escalator which motor is used?

In escalator 3 - φ IM is used because it has higher starting torque.

06․ The speed of rotation of 5

^{th}harmonic component in the stator of an induction motor is The speed of rotation of 5

^{th}harmonic component in stator of an induction motor is (1 / 5) times of the speed of synchronous motor.07․ In an induction motor, the no-load slip is generally equal to

For no-load the reactance becomes almost negligible and the rotor impedance now depends on only resistance. Further, if the rotor resistance is small the rotor current is large, so that motor works with a large torque (since torque ∝ current) which brings the speed near to synchronous speed. The slip is thus reduced to 1 % or less.

08․ Star - delta method of starting of motor is not possible in case of

Star - delta winding is three phase winding, and is only applicable in case of 3 - φ motors.
∴ A single phase induction motor can not be started by this method.

09․ If s is the slip and f is the supply frequency of an induction motor, the frequency of rotor current is given by

10․ In case of IM the torque is

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