How Does a DC Motor Single Phase Work?

A direct current (DC) electric motor essentially consists of a coil of wire or rotor that rotates in a magnetic field. Current is supplied to the coil, via two strips of carbon (brushes) that make contact with a split ring (commutator) as the coil rotates, and creates a magnetic field around it.

Magnetic Field

The coil is mounted on an axle between the poles of a permanent magnet. The interaction between the magnetic fields creates a turning force, or torque, on the coil, which causes it to rotate.

Brushes

When the coil turns through 90 degrees and reaches the horizontal position, the brushes temporarily lose contact with the coil and the current ceases. However, the coil continues to rotate under its own momentum, past this so-called break point, current flows in the opposite direction and the coil continues to rotate.

Speed

The speed of a DC motor depends on the current and voltage of the electricity flowing through the coil. Therefore, it can be controlled by taps in the coil winding or varying the voltage from the power supply.

References

• University of New South Wales: DC Motors
• Gizmo Highway: How Electric Motors Work