Electric Motors

This lesson explains how the motor effect is used to make a DC electric motor spin, including the role of the split-ring commutator, as required by the Edexcel GCSE Combined Science specification (1SC0).

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Structure of a Simple DC Motor

A simple DC motor has the following components:

Component	Role
Rectangular coil of wire	Carries the current; experiences a force in the magnetic field
Permanent magnets	Provide the external magnetic field (N and S poles)
Split-ring commutator	Two half-rings that reverse the current direction every half turn
Brushes (usually carbon)	Stationary contacts that press against the commutator and connect to the power supply
Axle	The coil (and commutator) rotate around this central shaft

graph LR
    subgraph "DC Motor — Side View"
    N["N pole"] --- Coil["Rectangular coil on axle"]
    Coil --- S["S pole"]
    Coil --- Comm["Split-ring commutator"]
    Comm --- Brush["Carbon brushes → to power supply"]
    end

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How the Motor Works

Step-by-Step