Basic Principles

  • Magnetman Visit this site to learn all about magnets. This guy loves magnets even more than I do! Lots of information and experiements here... make sure you follow the "next" links. 
  • Magnetic field lines.Visualize magnetic field lines, by showing the effect of a bar magnet on iron filings. 
  • Electric and Magnetic Fields Incredible Java applets to manipulate electric and magnetic fields. Includes a great one showing the rotating magnetic field in an induction motor. If you go up a level, there are a lot of other power electronics simulations.
  • Lenz's Law. Shows the relationships between induced magnetic fields, voltage, and current when a conductor is passed within the lines of force of a magnetic field.
  • Faraday's Experiment Illustrates Faraday's famous experiment with a moving magnet and a coil of wire. 
  • Electromagnetic induction Shows how a changing magnetic field can induce a voltage in another coil. Also show how a changing current creates a magnetic field. 
  • Capacators Shows charging and discharging of a capacitor.
  • AC Circuit Principles A site using animations to explain AC circuits, impedance, phase relations, resonance and RMS quantities.


  • Phasor diagrams Animated gif showing relationship between phasor and sin() wave. Also leading and lagging waves, and addition of phasors. 
  • Phasor Game A "game" to match the phasor to the corresponding sin wave.


  • Transformer University Everything you should know about transformers, and more, here. Be sure to read the transformer basics chapter.
  • Transformer simulaton. Allows you to visualize the relation between primary and secondary voltage as the turns ratio is changed.
  • Transformer Connections.Nice illustrated discussion of transformer connections.

Motors and Generators

  • AC Generator Action. Shows how a rotating coil immersed in a field produces an AC voltage. Also shows use of slip rings and the relation between RPM and frequency. 
  • DC Generator Action. Similar to the AC generator, but using a commutator rather than slip rings. 
  • Squirrel Cage Motor.Animated GIF which attempts to show what is going on in a squirrel cage rotor. 
  • Squirrel Cage Motors.Excellent website with lots of detailed information about squirrel cage motor principles. 
  • Electric MachinesWebsite supposedly has movies showing fields in motion, but I can't seem to make them play on my machine. Uses Windows Media Player.
  • Rotating Magnetic FieldThe rotating field in a three-phase motor is illustrated here, along with a similar animation showing what happens if the motor is single phased.
  • Youtube video of an induction motor being built.
  • Good video explaining the how a rotating magnetic field is developed.

Synchronous Motors

Motor Control