A motor that uses electrical energy in order to create mechanical work is called an electric motor. Although practically difficult, at times electric motors can also be run as generators. These motors find application in a large field of work, from industrial fans, blowers and pumps to household appliances, power tools and disk drives. Both direct current and alternating current is used to power an electric motor.in electric watches the smallest possible motor can be found. Medium-size motors are a suitable source of mechanical power for industrial uses. Large electric motors are used for propelling of large ships.
An electric motor works on the principle of generating mechanical force by the interactions of an electric current and a magnetic field. High efficiency electric motors have been built in the 19th century for commercial exploitation.
A simple two-pole electric motor consists of the following parts:
- Rotor or armature
- Brushes
- Axle
- Commutator
- Field magnet
The fundamental principle of magnetism is that : “ Opposite poles attract and like poles repel.” Therefore the north pole of a magnet will always get attracted to the south pole of another magnet and repelled by the north pole and vice-versa. These attracting and repelling forces inside the motor generates motion.
Thin wires are coiled around poles of a metal core in order to make the armature work like an electromagnet. The commutator, which basically is a pair of plates is attached to the axle of the armature. The commutator and brushes work simultaneously to let current flow to the electromagnet and also to invert the direction of its flow at just the right moment. Since the commutator is attached to the axle of the armature, they spin along with the magnet. The brushes are nothin but two pieces of metal which make contact with the commutator.
