EE8601_SSD_UNIT 3_QUIZ

Advantage of slip ring induction motor over squirrel cage induction motor is

• Suitability of high speeds

• Higher efficiency

• Higher power factor

• That it can be started using factor resistance

In an induction motor, the rotor input is 600 W and slip is 4%. The rotor copper loss is

• 700 W

• 625 W

• 600 W

• 650 W

The starting torque of a cage rotor induction motor can be increased by using rotor having

• Low inductance and low resistance

• Low inductance and high resistance

• High inductance and high resistance

• High inductance and low resistance

For smooth starting of three-phase squirrel cage induction motor, the starting method preferred is

• Rotor resistance

• Star-delta

• Auto-transformer

• Stator resistance

Large air gap in an induction motor results in

• Reduced noise

• Reduced pulsation losses

• Better cooling

• Increased overload capacity

The power factor of star connected induction motor is 0.5. On being connected in delta, the power factor will?

• Increase

• Reduce

• Remain the same

• Become zero

Simplest method of eliminating the harmonic induction torque is

• Integral slot winding

• Chording

• Skewing

• None of these

Any odd harmonic in the current of an induction motor will result in magnetic field which

• Is stationary relative to the field of the fundamental

• Rotates in forward direction at the harmonic speed

• Rotates in backward direction

• Oscillates at harmonic frequency

The drive generally used for lathe machines are

• Dc shunt motors

• Slip ring induction motors

• Synchronous motors

• Squirrel cage induction motors

Cogging of motor implies that motor

• Refuses to start at load

• Refuses to start at no load

• Runs at low speed and then stops

• Runs at very low speed