Question

what will happen if only magnetic field is reversed in dc motor​

Answer 1

Answer:

Explanation:

If the only one current direction ( either field or armature) is reversed, the field produced by that is reversed causing reversing the direction of rotation.

One reversing both the winding connection, both the fields produced by respective currents will reversed causing the net action in same direction, so when both the connections of winding of DC motor are reversed, there is no effect on direction of rotation.