SOLUTION

Universal motors are classified into two types

• Non-Compensated Type
• Compensated Type through Distributed Field

Non-Compensated Universal Motor: The non-compensated motor has two salient poles similar to 2-pole series d.c. motor except for that whole of its magnetic path is laminated.  The laminated stator is necessary because the flux is alternating when the motor is operated from a.c. supply. The armature is of wound type and similar to that of a small d.c. motor. It consists essentially of a laminated core having either straight or skewed slots and a commutator to which the leads of the armature winding are connected.

Compensated Type through Distributed Field: The distributed-field compensated type motor has a stator core similar to that of a split-phase motor and a wound armature similar to that of a small d.c. motor. The compensating winding is used to reduce the reactance voltage present in the armature when the motor runs on a.c. supply. This voltage is caused by the alternating flux by transformer action.