Similarity of Motor to Generator

Author: E.E. Kimberly

Inasmuch as the principal parts, except the shunt-field winding, of a machine built for use as a motor are identical with those intended for use in a generator, a d-c generator may be used as a d-c motor with only small sacrifice in performance. The shunt field of a machine designed for generator use is stronger than if the machine is intended for motor use, and therefore the possible operating-speed range by shunt-field control as a motor is somewhat greater than normal Also a machine with field coils designed for a motor will, when used as a self-excited generator, have a maximum voltage lower than may reasonably be expected of a machine designed for use as a generator.

In converting a motor to a generator, or vice versa, it is usually necessary to change the connection of the armature and the various field windings relative to each other.