How real electric motors work - School of Physics - The University of ...

Electric motors and generators
From Physclips: Mechanics with animations and film.
An introduction using animations and schematics to explain the physical principles of some of the different types of electric motors,
generators, alternators, linear motors and loudspeakers.
Schematics and operation of different types of motor
DC motors
Motors and generators
Alternators
Back emf
'Universal' motors
Build a simple motor
AC motors (synchronous and stepper motors)
Induction motors
Squirrel cage motors
Three phase induction motors
Linear motors
Homopolar motors and generators (separate page).
Loudspeakers
Transformers
AC vs DC generators
Some web resources
The schematics shown here are idealised, to make the principles obvious. For example, this animation has just one loop of wire, no
bearings and a very simple geometry. Real motors use the same principles, but their geometry is usually complicated. If you already
understand the basic principles of the various types of motors, you may want to go straight to the more complex and subtle cases
described in How real electric motors work, by Prof John Storey.
DC motors
A simple DC motor has a coil of wire that can rotate in a magnetic field. The current in the coil is supplied via two brushes that make
moving contact with a split ring. The coil lies in a steady magnetic field. The forces exerted on the current-carrying wires create a
torque on the coil.