DC Motors

This section is part of the HSC Physic syllabus Module 6: Electromagnetism under Applications of the Motor Effect.

Motors are the core of how so many mechanical systems work in today’s world. So let’s learn a little more about how a DC motor works. We’re going to cover the following information about a DC motor:

  • Components of a DC motor
  • How DC motors work
  • Torque generation in a DC motor


How DC motors work

The main components of a DC Motor are:

  • Stator
  • An armature
  • A rotor
  • A commutator with brushes.


The production of torque in a DC motor

The formulae we know for toque is:

\tau = Fd sin(\theta)

In a DC motor toque becomes:

\tau = B I h \frac{w/2}
  • B is the magnetic field
  • I is the current
  • H is the height of the wire
  • W is the width of the loop