An electric motor is a device which converts electrical energy into mechanical energy. It has revolutionized the world we live in. Without an electric motor, it would be tough to imagine the life today. The question is, who made this possible? Well, Michael Faraday, as a part of his experiment, gave the first demonstration of the effect of rotary motion. Back in September 1821, he dipper a wire into a pool of mercury and placed a permanent magnet on to it. Electric current was then allowed to pass through the wire, which made the wire rotate around the magnet. It was concluded that a closed circular magnetic field was created around the wire due to the current.
Now, this experiment created a machine which was practically useless at that time. But it gave rise to the concept which runs the world today. Without an electric motor, there wouldn’t be any electric fans, blenders, treadmills, washing machines, remote controlled cars and a lot more.
Labelled Diagram
As you may see in the diagram, a motor primarily has a rectangular coil ABCD, two strong magnets and a source to generate electric current. Let us look at all the parts of an electric motor one by one.
Parts of an Electric Motor
Let’s first look at the components of an electric motor.
- Two strong magnets for the magnetic field. These could be bar magnets or even horseshoe magnet.
- Power source- preferably a battery to generate the electric current.
- A rectangular coil ABCD on which the magnetic field is to be exhibited.
- Split Rings- These are used to rotate the coil. Split rings are also known as commutators.
- Carbon Brushes- These are there to create contact between the split rings so as to supply current to the rotor.
Working Principle
An electric motor works on the principle that when an electric current is passed through a conductor/coil which is placed in a strong magnetic field, a force begins to act on the conductor which makes it rotate on its axis. This rotation is now the mechanical energy. And as discussed earlier, the electrical energy is now converted into mechanical energy. Let’s now discuss in detail how this beautiful machine works.
Working of an Electric Motor
Magnets play a crucial role in the working of a motor. Just remember the basic concept of magnetism. Opposites attract and likes repel. And since electromagnetism is the key here, you should be aware of how an electromagnet works.
Let’s now create an electromagnet to better understand the concept. Take an iron nail and wrap an electric wire around it. Now connect the wire to a battery. This converts your nail into an electromagnet. Now place two strong magnets on both sides of the nail to see what happens. Just as you pass the electric current through the wire, the north pole of the electromagnet will repel the north pole of the magnet around it and this creates a circular motion in the nail. The nail would then come to a stop when it has completed a 180 degree turn. But your motor is still not ready for its job. The key is to make the electromagnet rotate another 180 degrees.
This magnetic filed flips when the electron run in opposite direction. In short, you change the direction of flow of electric current in the wire. This causes the nail to complete its turn. And if you manage to do at the right moment without any breaks, well, bingo. The motor is now ready.
