Question

Explain the working of electric motor and electric generator
(class 10 cbse question)

please help me with this question

Answer 1

A generator converts mechanical energy into electrical energy, while a motor does the opposite - it converts electrical energy into mechanical energy. Both devices work because of electromagnetic induction, which is when a voltage is induced by a changing magnetic field.

Answer 2

Electric motor is a rotating device which converts the electerical force into mechanical force...

Electric motor works on the principal that when a current carrying conductor kept in a magnetic field , it experiences a force , due to which it starts rotating.
The direction of force is given by Flemings left hand rule.


Working
=======
There is a rectangular coil ABCD insulated with copper wire placed between the poles of a strong magnet...
Coil is placed in such a way that the arms of a coil and field lines are perpendicular to each other...

The end of the coil are connected with two half rings R1 and R2 say ( also called split rings ). These rings can freely rotate along the axle of the coil.

Further , there are two stationary carbon brushes B1 and B2 say...which are attached to these rings ( see snap )....These brushes do not rotate with rings so the name called stationary carbon brushes...

These carbon brushes are connceted to the end of the battery a sshown in figure..
There is also a switch , which is used to close and open the circuit...or to make and break the circuit..

When switch is on...Current flows through the external circuit and then reaches to the one end of the coil then reaches to the arm AB...

When current flows to arm AB from A to B , arm AB experience a force upward and when current reaches to arm CD and flows from D to C , arm CD experiences a force downward.The direction of this force is given by Flemings left hand rule...

There is a couple.of forces acting on the oplosite sides of the two arm. These forces rotate the coil for half cycle. The path of the currwnt in first half revolution ( cycle ) is ABCD.

During this half cycles , the location of half rings gets changed , also the location of arms gets changed here...

For the next half cycle...current flows in the arms CD and AB from D to C and then from B to A...Again coil experiences a couple of force which forces it to make another half cycle. Now current flows in the path DCBA..

See the path of the current DCBA which is a reverse path of ABCD...The dirction of current is reverse...
The device which reverses the dirwction of current in electric motor is called commutator..Here split rings acts as a commutator..