Speed Control of a DC Series Motor

Abstract

This paper presents the speed control of DC series motor by using field control method,armature control method and voltage control method. In field control  method, a variable resistance is connected in parallel with series field winding to shunt some portion of the line current from the series field winding. Thus weakening the field and increasing the speed. While in armature control method, a variable resistance is directly connected in series with the supply to reduce the voltage available across the armature and hence the speed falls. For voltage control method, the motor is supplying with a variable voltage supply to change the speed of the motor. A laboratory experiment is designed to control the speed of dc series motor where a rheostat (variable resistor) is used to vary the field and armature resistance of the motor. The applied voltage is kept constant for both field control method and armature control method experiment. The result of the experiment shows at a constant supplied voltage, the speed of the motor increased when the flux and armature resistance decreased. Meanwhile, the speed of the motor increased when the terminal voltage increased. This study concluded that the speed of a series DC motor can be controlled
by varying the field, armature and supplied voltage.