How D.C. Motors Work

This lesson covers:

  1. How the motor effect can be used to generate a turning force from electricity
  2. What a 'split-ring commutator' is, and why it's required
  3. Three ways to increase the speed of the rotation caused by the motor effect
Diagram demonstrating Fleming's left hand rule and the direction of coil rotation between two magnets.

Using Fleming's left hand rule, which way will the coil above rotate?

Clockwise

Anticlockwise

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Diagram showing components of an electric motor with a blue device labelled A.

What do we call the blue device labelled A in the diagram above?

Split-ring commutator

Double disk

Double ring

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How the split ring commutator ensure the coil rotates in one direction


current / half / full / same / opposite


  1. The split-ring commutator swaps the positive and negative connections every turn.
  2. Therefore, the direction of the through the coil reverses every half turn.
  3. This means that the forces acting on the coil will always be acting in the direction.
  4. This causes the coil to rotate continuously in one direction.
half
current
same

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heat / motion / electricity


Overall, electric motors use to create a rotational .

electricity
motion

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Give three ways to increase the speed of rotation in an electric motor


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