You would be surprised to know how many electric motors are there in the room you are sitting in right now.
Starting from the laptop you must be reading this on, to the wall clock, the fan, toys, the mixer, the washing machine, the electric train, you name it.
Almost every and any appliance that has movement has an electric motor.
It’s only fair to learn how such an important machine works.
In the video, we explain the working of an electric motor by dissecting it and taking the kids through each component of the motor and its functions.
0:26 – What is a motor? – It is an electric machine that converts electrical energy into mechanical energy.
1:29 – A few applications of an electric motor – Toy cars, dancing dolls, ceiling fans, water pump.
2:32 – How does a motor work? – When the power is put into it at one end and an axle rotates at the other end giving the power to drive a machine of some kind. As shown in the dc motor diagram below.
Parts of motor:
The fundamental law of all magnets is that the opposite poles attract and the same poles repel.
That is, if we have two bar magnets with their ends marked “north” and “south,” then the north end of one magnet will attract the south end of the other. And, the north end of one magnet will repel the north end of the other.
14:45 – Since the magnets are fixed and cannot move and stick to each other, these attracting and repelling forces create rotational motion inside the electric motor.
18: 40 – Armature, It is nothing but coils of wire which acts as electromagnets when supplied with power.
The north end of this electromagnet would be repelled from the north end of the permanent magnet and attracted to the south end of the permanent magnet.
This repulsion causes the armature to move half a turn. To make the armature complete that turn, the direction of the current to be changed now.
22:30 – The reversing of the current direction is achieved by the commutator while the brushes carry the current to the commutator.
Finally, The axle which holds the armature and the commutator rotates and moves whatever is attached to it.
Now, moving on to the most exciting part of learning – Making!
Having learned the working of an electric motor and knowing how simple the underlying principle is, you can now build an electric motor model yourself using easily available materials at home.
Do your kids have any questions? Do ask us in the comment box below.
at 8:48 am
Why do like poles of magnets attract and opposite poles repel?
at 8:53 am
The electrons in the atoms of the magnet spin in only one direction, unlike other non-magnetic materials. This single direction spinning creates a magnetic force that flows from the north pole to the south pole outside of the magnet. Trying to connect the south pole to the south pole or the north pole to the north pole is like trying to force the electrons to reverse the direction that they are spinning. That is why the like poles repel each other.
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Why are the poles of magnet given names as south and north?
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One of the explanations is that, if we hang a magnet from a thread, the magnet’s north pole points (almost) towards the north direction. This is because the Earth’s center is a large, weak magnet. Our little, strong magnet lines up with Earth’s magnetic core, so it points north. That’s how a magnetic compass works.