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The electric motor

The electric motor is a device that converts electrical energy into rotational kinetic energy by the action of the force on a coil pivoted in a magnetic field. A coil in a magnetic field experiences an equal but opposite force on its two sides and so the coil twists.

If the coil is in the position shown in the first diagram there will be an upward force on side (1) of the coil and a downward force on side (2) of the coil. The coil will therefore start to twist in an anticlockwise direction.

The inertia of the coil and core keeps it turning until the input wires make contact with the ends of the coil again. This time the positive wire touches side (2) and the negative wire touches side (1). Side (2) now moves up and side (1) moves down the coil continues to turn in an anticlockwise direction. This process then continues and so the coil spins.

© Keith Gibbs 2011