Wednesday, 25 June 2014

Direction of Rotation of DC Motor

Direction of Rotation of DC Motor Points : Direction of Rotation of DC Motor It is evident that if the armature current were reversed by reversing the armature leads, but leaving the field polarity the same, torque would be developed in a counters. clockwise direction. Likewise, if the field polarity were reversed leaving the armature current torque would be developed in a counter-clockwise direction. However, if both, the direction of the armature current and field polarity were revelries, torque would be developed in clock-wise direction as before. Hence the direction of rotation of a motor can be reversed by reversing the current through either the armature winding or the field coils. If the current through both is reversed, the motor will continue to rotate in the same direction as before.

a. IIllustrates a dc series motor with the direction of rotation assumed to be clockwise.
b. Shows the field winding interchanged giving reversed rotation.
c. Shows the alternative method when the armature connections at the brushes are interchanged.
d. Illustrates the methods of reversing the direction of rotation of a dc shunt motor.

The direction of rotation of a dc compound motor may be conveniently reversed by reversing the connections to the armature, as illustrated. The reversal of the field connections involve both shunt and series field windings.

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