In many circumstances we can use these eddy currents to our advantage. One of the most common applications of eddy currents is in electromagnetic braking in moving vehicles. The Tower of Terror (Dreamworld) electromagnetically accelerates its passengers to a massive 160 kph in seven seconds, climbing to almost 38 storeys high. If you have survived this ride it is because of eddy currents.
Eddy currents are used to provide the braking force between the ride and the vertical column that holds the ride up. The column has a metal plate attached to it and a number of very powerful magnets attached to the ride. These magnets produce a very strong magnetic field (high flux density). As the magnets pass the metal plate they induce a series of eddy currents in the plates. These currents produce a magnetic field that opposes the motion that caused them. The ride was moving down to cause the eddy currents to be produced, so the magnetic force due to these eddy currents is up all the time, thus slowing the ride.
To see some graphics of the same type of ride at Australia’s Wonderland, (now closed) follow the link below:
We will look at some examples of how eddy currents can be used to slow down a moving metal plate.