ACM 1

A 2-pole, 3-phase, ______ Hz induction motor is operating at a speed of 550 rpm. The frequency of the rotor current of the motor in Hz is 2.

• 9.37

• 9.12

Stator voltage control for the speed control of induction motor is suitable for

• Fan and Pump Drive

• Drive of a crane

• Running as the generator

• Constant Load drive

Objective of Rotor resistance starter is...

• To limit the starting current

• To control the starting torque

• To vary the speed

• All the above

Slip ring induction motor controlled by

• Rotor resistance starter

• Solid state rotor resistance starter

• both a & b

a rotating magnetic field is created by :

• applying three phase waveforms to rotor winding placed 120 degrees apart.

• applying three phase line voltages to stator winding via sliprings

• applying three phase line voltages to red yellow and blue stator windings.

• applying three phase phase voltages to a delta connected load.

a cage rotor consists of

• laminated soft iron with copper or iron end rings

• laminated soft iron core containing longitudinal copper or iron bars which are capped at each end via a shorting plate.

• laminated silica steel core containing longitudinal copper bars shorted at one end only

• laminated soft iron core with three phase star connected windings and slip rings,

slip is defined as :

• the difference between synchronous speed and rotor speed

• the difference between rotor speed and synchronous speed

• synchronous speed - rotor speed / rotor speed

• (rotor speed - synchronous speed ) / synchronous speed