1. Principle:
When electricity flow through the inductor it becomes electromagnet which is attracted a unlike poles and repel like poles. To keep rotate the motor the electricity should be in alternating polarity or on and off state which keep the motor in rotating condition even the electricity cut off for half cycle.
2. Working:
¨ When current flow through the coil it produce electromagnet around it and becomes an electromagnet. It's has also North and South Pole which is attract and repeal other magnet.
¨ Our coil becomes an electromagnet when the bare copper half of the armature wires touch the bare of the bare wire of the supports, and electricity flow into the coil. The electromagnet which has North Pole which is attracted by South Pole of a magnet. A South Pole is attracted by North Pole of a magnet.
¨ When current flow through the coil it form a invisible magnet – which perpendicular to the magnetic field of the regular magnet while coil is parallel to the table.
¨ Since the poles point left and right, they have to move in order to line up with the magnet at the bottom, whose poles are aligned up and down. So the coil rotates to line up with the magnet.
¨ But once the coil exactly lined up with the magnet, the insulation half of the wire is now touching the supports instead of the bare half. The electricity is cut off, and the coil is no longer an electromagnet. This leaves it free to coast on around until the bare copper can again touch the bare support, and start whole process over again.
3. Construction:
Ø Make this motor from your store room having electronic instruments. We required a transformer and speaker magnet. Using transformer we can disassemble the transformer for coil and use a magnet from speaker.
Ø Take along with a pipe and wrap coil around the pipe around 10 to 15 turns. Its look like a simple inductor as shown in below diagram.
Ø Now make as tight and keep closer the coil. If they are more closure they make strong magnetic field around it. Tie these coils by wires or a cello tape.
Ø Use a copper wire as pole which is used to support the rotating coil as shown in fig. Now the remove the insulation around the copper wire using razor by scraping. Remember that remove the insulation the upper base for regular contact rotating coil while lower base used for the wire contact to flow current flow battery.

4. Tips and Tricks:
Ø Hold a magnet over the top of the motor while it is running. As you move the magnet 
closer to the spinning coil, one of two things will happen. Either the motor will stop, or it will run faster. Which of these happens will depend on which pole of the magnet you have facing the coil. Make sure you hold the motor down so the magnets will not jump together and crush the little motor!

closer to the spinning coil, one of two things will happen. Either the motor will stop, or it will run faster. Which of these happens will depend on which pole of the magnet you have facing the coil. Make sure you hold the motor down so the magnets will not jump together and crush the little motor!
Ø There is another way to speed up the motor. The motor only gets electricity during half of the cycle. During the other half, the insulation blocks the flow of current. This is necessary because once the coil has spun around to face the magnet, if we let the current continue to flow, it will stay stuck there, facing the magnetic pole to which it is attracted.
Ø But suppose instead of just stopping the current, we reversed it, so the north pole of the electromagnet became the south pole, and vice versa. The coil would want to flip over again! And since it is already going in one direction that is the direction it will choose to continue going (due to the inertia and momentum of the coil).
Ø Below is a photo of a motor built this way. The connections are hidden underneath the base for neatness; you can see the wires resting on the top of the axles and know that they are connected to the opposite supports.
Ø On one half of the cycle, the bare half of the axle will face down and touch the bare wire of the support, just like before. On the other half of the cycle, the bare half of the axle will touch the new wires that are resting on top of the axle. Since these wires are connected to the opposite supports, the current will flow in the opposite direction. The motor will get two kicks per cycle instead of one, and will never be coasting, it will always have power. It will go twice as fast.
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