The Electric Motor

Electric motor is used to convert electrical energy into mechanical energy. Let’s go through an instance: What does the mixer in your house do for you? The rotating blades mash and mix things for you. And if someone were to ask you how that works, what would you say? You would probably say that it works on electricity. Well that’s not incorrect. Motors convert electric energy to mechanical work. The opposite is done by generators that convert mechanical work to electrical energy.

Principle of an Electric Motor

The functioning principle of the electric motor is based on the fact that a current carrying conductor produces a magnetic field around it. Imagine the following situation.

Take two bar magnets and keep the poles facing each other with a small space in between. Now take a small length of a conducting wire and make a loop. Keep this loop in between the space between the magnets such that is still within the sphere of influence of the magnets. Now for the last bit. Connect the ends of the loop to battery terminals.

Once electricity flows through your simple circuit you will notice that your loop “moves”. So why does this happen? The magnetic field of the magnets interfere with that produced due to electric current flowing in the conductor. Since the loop has become a magnet, one side of it will be attracted to the north pole of the magnet and the other to the south pole. This causes the loop to continuously rotate. This is the principle of working of an electric motor.

Parts of an Electric Motor

A simple motor has the following parts:

  • A power supply – mostly DC for a simple motor.
  • Field Magnet – could be a permanent magnet or an electromagnet.
  • An Armature or rotor
  • Commutator
  • Brushes
  • AxleElectric Motor

Uses of an Electric Motor

Electric motors are used in a variety of applications. Some of them are listed below

  • Drills
  • Water Pumps
  • Hard Disc Drives
  • Washing Machines
  • Industrial Equipment

You can expect the efficiency of a functioning motor to be around 70 – 85% as the remaining energy is wasted in heat production and sounds emitted.

Practise This Question

In Fleming’s left hand rule, the middle finger represents the direction of magnetic field.