Eddy Currents

Circulating currents within inductor core material caused by magnetic lines of force cutting across the core in a direction which induces a voltage in the core material.

They are the main cause of heating in electric motors and transformers. For this reason iron cores are made from many thin layers that are insulated from each other so that the eddy current cannot flow between them.

There are a number of uses:

• Induction heating.
• Mechanical damping.
• Electrical braking.
• Speed indicators.
• Non-destructive testing.

See also: Armature Losses, Induction Hardening.