Electrical Machines
Ward-Leonard system for controlling the speed of a DC motor is used where

 The speed in both the direction is required.
 All of above.
 The accuracy in speed control is required.
 Very fine speed control over the whole range from zero to normal speed is required.

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
Cogging and crawling are phenomena associated with

 the former at a fraction of its rate speed and the latter during starting.
 the former during starting and the latter at a fraction of its rated speed.
 cage induction machines and they are essentially the same.
 any of the above.

ANSWER DOWNLOAD EXAMIANS APP