A Simple Electric Motor

An electrical motor is a device that converts electrical energy to mechanical energy. It works on the principle of the interactions between the magnetic fields of a permanent magnet and the field generated around a coil conducting electricity. The attractive and repulsive forces between the magnet and the coil create rotational motion.

A simple electric motor consists of the following parts.

  1. A permanent magnet
  2. Armature or rotor
    This consists of a thin copper wire coiled around an iron core, hence when electric current flows it acts as an electromagnet. In the case of a simple motor this is a wire loop.
  3. Commutator
    A Commutator is a copper ring split in two halves. In a simple electric motor each half is connected to the ends of the wire loop. In practise they are connected to the axle.
  4. Brushes
    The brushes connect the wire loop or armature to the power supply
  5. Axle
    In electric motors the commutator is attached to the axle. The axle transfers the rotational motion.
  6. Power supply (battery)

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Improving a Motor

An electric motor can be made powerful by the following;

  • By increasing the number of turns that are wound on the coil. In the case of the wire loop in the animation this would mean winding to form two loops.

  • By winding the electrical wire around a soft iron core so that the magnetic field is stronger.

  • By replacing the permanent magnet with a electromagnet which can gice a stronger magnetic field.

  • By winding extras coils around the core. Similar to having two separate wire loops in the animation above however this would mean splitting the commutator into 4 parts.