DC Motors Forward and Reverse Operation

 
By 10 August 2014
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In case of a DC series motor, the direction of the motor can be reversed either by changing the direction of the armature current or the field current.

In the same way for a shunt motor, the direction of the motor can be changed either by changing the direction of the armature current or field current. In the case of a compound motor, the direction of rotation can be reversed by changing the direction of the armature current or of both field currents, i.e., series and shunt field windings.

The industrial standard, however, is to change the armature current direction, keeping the direction of current in the field unchanged.

This is shown in Figure 4.16. At the motor terminal box, the starter cable is changed from A to AA, and the interconnecting link is changed from Y to AA. Any type of DC machine can be reversed by reversing the current flow in the armature and interpoles. It should be noted that the brush position might need to be changed to suit the new rotation.