A simple D.C motor

• A DC motor converts direct electric current into kinetic energy
• It has a stator
• Stator-a stationary magnet found within a DC motor
• It also has a many coils wound on an armature
• This is called a rotor
• The coils are mounted on an axle which rotates in a magnetic coil

The internal components of a DC Motor. Image credit blogspot.com

• Each end of the coil is connected to the half of a split ring
• The split ring is also known as a commutator
• The commutator turns with the coil and makes contact with the two carbon brushes
• That it press lightly against the commutator split rings
• Current is fed into the coil through the carbon brushes
• The coil rotates until it is in vertical position
• Its momentum (inertia) carries it past the vertical position
• The two halves change contact from one brush to another
• The direction of current is now reversed in the coil
• The other half is also forced downwards thus maintaining rotation in one direction
• Real world motors have a more sophisticated design but they still operate on the same principle
• Some of these modifications include:
• many turns in the coil,
• A soft iron cylinder round which coils are wound
• The coil and this core are known as an armature
• A strong magnet
• DC motors are used where variation in speed is needed
• For example electric cars and trains
• They are also used in toys and drones

Uses of Motors

• Motors be they DC motors or AC motors (AC motors are beyond the scope of the O level syllabus) have a number of uses
• They are used to drive devices such as:
• pumps in mines and on farms
• lifts in buildings
• to power electric lawnmowers
• electric drills
• electric saws
• Motors can also be found:
• in fans
• In washing
• electric cars

To access more topics go to the Combined Science Notes page.