Physics P3 3.1

The Electric Motor

An electric motor is designed to use the motor effect. We can control the speed of an electric motor by changing the current. Also, we can reverse its turning direction by reversing the current. 

The simple motor shown above consists of a rectangular coil of insulated wire (the armature coil) that is forced to rotate. The coil is connected via two metal or graphite "brushes" to the battery. The brushes press onto a metal "split-ring" commutator fixed to the coil. 

When a current is passed through the coil, the coil spins because:

• a force acts on each side of the coil due to the…