Electrical Engineering ⇒ Topic : Speed of d.c series motor by Rheostatic control

Rheostatic control

This method consists of obtaining reduced speeds by the insertion of external series resistance in the armature circuit. It can be used with series, shunt and compound motors ; for the last two types, the series resistor must be connected between the shunt field and the armature, not between line and the motor.

        Fig. (1) Field divertor method                          Fig. (2) Armature divertor             Fig. (3)Tapped field contro for

        method of speed control of D.C.                   method of speed control of D.C.           D.C. series motor. (This

         motor                                                               series motor                                  method is often employed in electric traction).

                        Fig.(1) . Paralleling field coils method for speed control of D.C. series motor.

                                                    (This method is used for fan motors )

It is common method of speed control for series in motors and is generally analogous in action to wound-rotor induction motor control by series rotor resistance