Electrical Machines
The slight curvature at the lower end of the OCC of a self excited DC generator is due to

  residual flux.
  high speed.
  magnetic inertia.
  high field resistance.

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
Cogging and crawling are phenomena associated with

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

ANSWER DOWNLOAD EXAMIANS APP