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Unlike mechanical brakes, which are based on friction and kinetic energy, eddy current brakes rely on electromagnetism to stop objects from moving.
Eddy currents are created when a conductor passes through a magnetic field, which creates opposing forces that spin inside the conductor. According to Lenz’s law, an eddy current produces a magnetic field that is in opposition to the magnetic field that produced it, and therefore eddy currents are an inverse response to the source magnetic field. This reaction between electromagnetic forces happens to be ideal for clean deceleration.
As a modern kind of technology, eddy current braking has numerous benefits over mechanical brakes. It is ideal for many kinds of machinery due to a lack of physical contact between components, which makes eddy current brakes very low-maintenance. The physical and economic advantages associated with eddy current brakes have made them a popular option among mechanical engineers.
In one basic design for an eddy current brake, a non-ferromagnetic conductive disc rotates perpendicularly through a toroidal magnetic field. As the disc rotates, it induces eddy currents. Power is then dissipated throughout the disk to produce a braking torque force.
Electromagnets are commonly used for eddy current brakes, rather than permanent magnets, because the power of the magnetic field can be changed, and thus the braking effect as well. One major issue with eddy current brakes is that they cannot offer a “holding” torque. Therefore, they are often used in conjunction with standard mechanical brakes.
Eddy current brakes have numerous applications, a few examples of which are listed below.
Exercise Equipment
Probably the most typical eddy current brakes can be seen is in the gym. A lot of modern exercise equipment uses these low-maintenance brakes to vary resistance levels and eliminate potentially-harmful abrupt shifts in pace. The result is a safer, more enjoyable exercise experience.
Power Tools and Industrial Equipment
One of the main uses of eddy current breaks is for emergency shut-off purposes in industrial equipment and power tools. When triggered, eddy current brakes can safely bring a high-powered machine to a rapid stop.
Eddy current braking is also used in these types of machine even non-emergency situation, just to stop them from running.
Amusement Park Rides
Often seen in roller coasters and other amusement park rides, eddy current brakes are now essential to the modern amusement park experience.
The high-speed nature amusement park rides make for a lot of fun, but big heavy machines moving at high velocities need a very secure and safe braking system. In addition to providing a high level of safety, eddy currents also allow rides to switch direction and speed rapidly while maintaining safety for everybody on board.
By making use of the force generated of eddy currents, a roller coaster can automatically slow down over certain designated spots on the track. This braking system is normally used after a rollercoaster run or after the train goes through a big jump in speed. Because of the nature of eddy current brakes, the more rapidly a roller coaster is moving, the faster the brakes can slow it down.
Eddy current brakes are also great for amusement parks because they are not affected by weather and need very little maintenance.
High-Speed Trains
Eddy currents are a safe and sound method to slowing down a speeding train while delivering comfort and ease for riders. Through the use of this technology, commuter and even streetcar trains can safely achieve faster speeds and while maintaining higher safety levels.
Given that countries are increasingly seeking to address issues related to commuting and urban life, high-speed train travel is being seen as a way to accommodate greater demands on public transit systems.
Sources and Further Reading
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