A d.c motor is a machine that converts electrical energy to mechanical energy. In opposite this d.c machine works as a generator i.e converting mechanical energy.
MAIN CONSTRUCTIONAL FEATURES
A motor has two main parts :-
- Stator – is the stationary member consisting of the field system.
- Rotor – is the rotating member which houses the armature windings. it is also known as armature.
other parts include :-
- Pole core – is a bunch of steel sheets stacked and riveted together and bolted to a yoke.
- Yoke – made of steel and its purpose is to frame the motor.
- Armature core – is a laminated cylinder mounted on the shaft separated from field poles with an air gap that allows it to rotate freely.
- Stator pole shoe – it should be laminated just like the armature to reduce eddy current loss.
- Commutator – is a cylindrical body mounted on the shaft along with the armature. Brushes are placed on the commutator surface to supply or collect current to the armature coils through the commutator segments. work of the commutator is to convert alternating current induced in the armature conductors into direct current in the external circuit in case of generator operation i.e in a generator.
HOW A D.C MOTOR WORKS
A d.c motor is a machine works in the principle of the flemings left hand rule. If we stretch the first finger, second finger and thumb of our left hand to be perpendicular to each other. The direction of magnetic field is represented by the first finger, direction of the current is represented by second finger then the thumb represents the direction of the force experienced by the current carrying conductor. in this case when a electric current passes through a coil in a magnetic field, the magnetic force produces a torque which turns the d.c motor. To ensure smooth rotation, the motor should have many windings.