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.
- A permanent magnet
- 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. - 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. - Brushes
The brushes connect the wire loop or armature to the power supply - Axle
In electric motors the commutator is attached to the axle. The axle transfers the rotational motion. - Power supply (battery)
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.