Rotor rheostat control method of speed control is used for

Which is of the following data is required to draw the circle diagram for an induction motor?

A. Block rotor test only

B. No load test only

C. Block rotor test and no-load test

D. Block rotor test, no-load test and stator resistance test

Slip rings are usually made of

A. Copper

B. Carbon

C. Phosphor bronze

D. Aluminium

The starting torque of a three phase induction motor can be increased by

A. Increasing slip

B. Increasing current

C. Both (A) and (B)

D. None of the above

Rotor rheostat control method of speed control is used for

A. Squirrel-cage induction motors only

B. Slip ring induction motors only

C. Both (A) and (B)

D. None of the above