The DC Motor/Generator is a dc machine mounted in a full-size EMS module. It can operate independently as a dc motor or a dc generator. The armature, shunt field, and series field windings are terminated separately on the faceplate to permit long and short shunt as well as cumulatively and differentially compounded motor and generator connections. This machine is fitted with exposed movable brushes to allow students to study the effect of armature reaction and commutation while the machine is operating under load.

An independent, circuit-breaker protected, shunt-field rheostat is mounted on the faceplate for motor speed control or generator output voltage adjustment. The speed of the DC Motor/Generator can be controlled using the Thyristor Speed Controller in both the open-loop and closed-loop modes of control.