Through this article you will be able to understand construction and working of electric generator and electric motor. Electric generators, about which you may have read many times in books, are very simple to construct and can be used as mini school project. Many other projects can also be made using this experiment which can be used in science fair and exhibitions at school level.

Working Principle of Electric Generator:

Metals, as you know, are very good conductor of electricity because they contain free electrons that transfer energy from one end to other. When a coil is kept in a changing/ fluctuating magnetic field, electric voltage/potential difference occurs across the coil. This difference in potential forces these free electrons in the wire. In simple words, change in magnetic field causes electric current in the coils kept in that magnetic field. After doing the project you will have better understanding of its working.

Working Principle of Electric Motor:

The construction of electric motor is same as electric generator. In this, alternating current (AC) is passed through the coils which rotate the magnet kept inside the coil. This rotating magnet turns the motor shaft.

Now let’s check out the construction and working of electric generator.

Materials Required:

Small cylindrical films roll can, metal rod (spokes), straw (for bush bearing), strong magnets, insulated copper coils, electric wires, one LED.

Steps of Construction of Electric generator:


Take the film roll can and make two holes at equal height as shown. Holes should me at equal heights and take proper care while making holes.


Use two cut straw pieces and insert them each in the holes. These straw pieces will serve as bush bearings for smooth motion of magnet inside the can.


Now insert the metallic spoke containing magnet inside these straw pieces, as shown in the figure. After inserting the metallic spoke, make sure the magnet spins freely on its axis. This freely moving magnet will create the fluctuating magnetic field to produce the voltage potential required for the motion of free electron, as mentioned in the working of electric generators above.


Now take the insulated copper coil and wind it around the film can, as shown. Make approximately 1000 turns. More the number of turns more will be the voltage produced.


Now at the two ends of the coil thus wounded, connect one LED with the help of electric wires. Make sure the connection is right and the circuit is complete. If the circuit is not complete, the free electrons will not move and hence no electric current.


Now to the end of metallic spoke, connect a turbine/wheel as shown. This will help in turning the magnets around the axis. This completes the construction of electric generator.

Working of electric generator:

Turning the turbine wheel around the axis causes the magnets to spin. This movement of magnets causes change in magnetic field. This produces electric voltage which generates the electric current through the coils. LED will glow intermittently because the current thus developed is alternating current (AC).

Electric generators are used to produce electricity that we use. Basic principle of working is same for all generators, only the method of turning the turbine wheel changes.

This electric generator project can be used in making various other school science projects also. Check out this space regularly to have more project ideas.

I am a "Mechanical Engineer" and a part time Blogger. I love to write technical stuff specifically. I have an experience in automobile and design field. Now I want to share my Engineering knowledge with you.


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