Under which of the following conditions is a DC motor provided with compensating winding used?
1. Wide range of speed control above normal
2. Wide range of steady load variation with no speed control
3. Wide range of rapid variation in load.
Select the correct answer using the codes given below:
(a) 1, 2 and 3 (b) 2 and 3 (c) 1 and 2 (d) 1 and 3