Question

What is the advantage of armature in a motor?
A) It increases the magnetic effect of a motor
B) It increases magnetic lines of force
C) Both
D) None

Answer 1

Hint:The armature induced electromagnetic force when the magnetic flux linking to it changes with time. The induction of EMF follows Faraday’s law of electromagnetic induction.
The armature is also called the power producing component of an electric motor.

Complete step-by-step solution:
An armature is defined as the component of an electric motor or an electric generator that carries alternating current (AC). Using a commutator, the armature conducts AC current on Direct current machines.
The armature winding is present in the armature and supported by the armature. In an electric motor the magnetic field is produced by an electromagnet or the permanent magnet. The armature winding interacts with the magnetic field formed in the air gap. If the magnetic field varies then the electric flux linking to the winding of armature will also change.
Using Faraday’s law of electromagnetic induction, a changing magnetic flux with time induces EMF.
When the armature is used as an electric motor, due to relative motion between flux produced by the field winding and the flux produced by the armature winding the EMF is induced.
This EMF will oppose the current of an armature. Due to opposition of current in armature by the EMF, the torque produced in the rotor. And in this way the electrical power is converted into mechanical power. The torque produced in the rotor is transferred to rotate other devices via a shaft.
Magnetic field is produced by the permanent magnet or the electromagnet produced in the motor. So, armature has no contribution in increasing the magnetic effect of the motor.
Magnetic field lines of force depend on the magnetic strength of the permanent magnet or electromagnet.

Therefore, option D is the correct option.

Note:The armature winding conducts alternating current events on the direct current machine due to commutator.
Depending on the type of electric machine, the armature can be either a rotating part or the stationary part.