Quiz sheet for operating principles of three phase induction motors

The direction of rotation of the rotating magnetic field is determined by the 

A) phase sequence

B) direction of the windings

C) shape of the rotor

D) rotor currents

ANSWER: A

The field strength of the RMF of a three phase squirrel cage induction motor is 

A) one and a half times the maximum of a single phase

B) three times the RMS of a single phase

C) double the maximum of a single phase

D) the same as for a single phase motor

ANSWER: A

The ROTOR of three phase squirrel cage induction motor requires

A) No electrical connection 

B) DC to be connected 

C) Resistors to be added 

D) A three phase supply to be connected to it

ANSWER: A

The simplest way to reverse the direction of a three phase induction motor is to. 

A) swap two phases of the supply leads

B) change the polarity of the rotor but not the field

C) rewind the rotor

D) change the phase sequence in the rotor

ANSWER: A

The speed of the rotating magnetic field in an induction motor is proportional to :

A) stator frequency

B) supply voltage 

C) supply current 

D) rotor frequency

ANSWER: A

The speed of the rotating magnetic field is referred to as the 

A) synchronous speed

B) run speed

C) slip speed

D) rotor speed

ANSWER: A


Last modified: Friday, 28 May 2021, 6:16 PM