Electric Motor

Parts of the Motor

Armature or rotor

Commutator

Brushes

Axle

Field magnet

DC power supply of some sort

Electric Motor

An electromagnet is the basis of an electric motor
A motor uses magnets to create motion.
Opposites attract and likes repel. Inside an electric motor, these attracting and repelling forces create rotational motion.
A motor consist of two magnets.

Armature

The armature is an electromagnet made by coiling thin wire around two or more poles of a metal core.
The armature has an axle, and the commutator is attached to the axle.
When you run electricity into this electromagnet, it creates a magnetic field in the armature that attracts and repels the magnets in the stater. So the armature spins through 180 degrees.

To keep it spinning, you have to change the poles of the electromagnet.

Commutator and Brushes

Commutator is simply a pair of plates attached to the axle. These plates provide the two connections for the coil of the electromagnet.
Commutator and brushes work together to let current flow to the electromagnet, and also to flip the direction that the electrons are flowing at just the right moment.
The contacts of the commutator are attached to the axle of the electromagnet, so they spin with the magnet. The brushes are just two pieces of springy metal or carbon that make contact with the contacts of the commutator.


Force on a current carrying conductor
The basic requirements are

Magnetic field

Current flowing across the magnetic field
A force is exerted on any current carrying conductor that crosses a magnetic field. The direction of the force depends on the direction of field and the current. This force which every motor make use of is known as motor effect

Fleming's left hand rule

According to Fleming's left hand rule, if the thumb, fore-finger and middle finger of the left hand are stretched perpendicular to each other and if the fore finger represents the direction of magnetic field, the middle finger represents the direction of current, then the thumb represents the direction of force. Fleming's left hand rule is applicable for motors.

Posted in: Physics