1000+ Poly Phase Induction Motor MCQ Questions & Answers - 2

Question: 6

Slip rings for induction motors are made of

(A) cobalt steel

(B) carbon

(C) aluminium

(D) phosphor bronze

Question: 7

The speed of a three phase cage rotor induction motor depends on

(A) number of poles and frequency of the supply

(B) frequency of supply only

(C) input voltage

(D) number of poles only

Question: 8

In three phase induction motors sometimes copper bars are placed deep in the rotor to

(A) improve power factor

(B) improve efficiency

(C) reduce copper losses

(D) improve starting torque

Question: 9

In three phase squirrel cage induction motors

(A) rotor conductors are connected to insulation

(B) rotor conductors are kept open

(C) rotor conductors are short circuited through end rings

(D) rotor conductor ends are short circuited through slip rings

Question: 10

The frame of an induction motor is usually made of

(A) bronze

(B) aluminium

(C) cast iron

(D) silicon steel