SOLUTION

The universal motor is often referred to as an AC series motor. This motor is very similar to a DC series motor in its construction in that it contains a wound armature and brushes. The universal motor, however, has the addition of a compensating winding.

Reversing Direction of Rotation of Universal Motor

The direction of rotation of a universal motor can be changed by either:

(i) Reversing the field connection with respect to those of armature

(ii) By using two field windings wound on the core in opposite directions so that the one connected in series with armature gives clockwise rotation, while the other in series with the armature gives counterclockwise rotation.

The second method, i.e., the two field method is used in applications such as motor-operated rheostats and servo systems. This method has somewhat simpler connections than the first method.

The direction of rotation of the universal motor can be changed in the same manner as changing the direction of rotation of a DC series motor. Reversing the direction of rotation of a universal motor happens by reversing the direction of current in either the series field or the armature but not both.