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Question
Draw and label the diagram of a simple D.C. motor.
(a) Explain the rotation of the coil, giving a reason for your answer.
(b) How can you reverse the direction of rotation of the armature?
(c) How can you increase the speed of rotation of the motor?
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Solution
(a) The coil rotates because equal and opposi te forces act on its arms which form a couple.
(b) The direct ion of rotation of armature can be reversed by interchanging the connections at the terminals of the battery joined to the brushes of the motor.
(c) The speed of rotation of the motor can be increased by increasing the current through the coil or by increasing the number of turns in the coil and by increasing the strength of the magnetic field.
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