Question

State the position of armature coil relative to the direction of magnetic field, in a D. C. motor when the deflecting couple acting an the coil is (i) maximum, (ii) minimum. 

Answer 1

(i) The deflecting couple acting on the coil is maximum when the plane of the coil is parallel to the direction of magnetic field. 

(ii) The deflecting couple acting on the coil is minimum when the plane of the coil is normal to the direction of magnetic field.