Home / Topics / Magnetism & Induction
Eddy current braking
Intermediate
Magnets slow motion in conductors.
A moving conductor in a magnetic field has eddy currents that oppose its motion, giving smooth, contactless braking used on trains and roller coasters.
Magnetic brakes in coasters work at any speed with no wear.
Force decreases as speed falls, so it can't hold at rest.
In more detail
Eddy current braking slows a moving conductor by inducing currents that create forces opposing its motion. It produces smooth braking without contact or wear.
Real-world uses
- Trains and roller coasters use eddy current brakes.
- Some exercise bikes use eddy current resistance.
- Trains and roller coasters use eddy current brakes, where magnets passing over metal plates slow them smoothly.
Open the interactive lesson, with simulation and quiz →
Frequently asked questions
Does it stop completely?
It slows the object, but it does not hold it still without another mechanism.
Why no wear?
Because the braking force comes from magnetic interaction, not friction.
Why does the brake not wear out?
There is no contact between the magnet and the metal, so no friction wears the parts down.
Related topics in Magnetism & Induction
Lenz's law · Motional emf · Eddy currents · Self-inductance · Inductance of a solenoid · Energy in an inductor