Electromagnetic Eddy Current Brake: What Are They & How Do They Function?

The electromagnetic brake market is diverse. The single-face design is the most popular variant. Magnetic brakes work electrically yet manually transfer torque. Because of this, they were formerly known as Electromechanical clutches and brakes.   

EM began to be called electromagnetic rather than electromechanical, emphasizing their actuation approach instead of their physical operation. Almost seventy years ago, electromagnetic eddy current brakes first gained popularity. Since then, there have been many applications and brake designs, but the single-face electromagnetic brake's fundamental operation has remained the same. 

Operation  

A brake has only three primary components: the field, armature, and hub. Typically, the magnetic field is fastened to a stable object. Hence, the stopping torque is transferred into the field housing when the armature is drawn to the area, slowing the load. This can occur extremely quickly. However, the voltage or current given to the field can regulate how long the brakes stop. As soon as the area deteriorates, flux rapidly decreases, and the armature separates. A spring keeps the armature from its field face surface at a specific air gap.  

Importance of Voltage/Current  

Any magnetic field's strength could be altered by varying the wire's size and density. A coil made of copper wire is used in EM brakes to generate a magnetic field.  

As long as the proper operating voltage and current are used with the right brake, the fields of EM brakes can be created to operate at virtually any DC voltage, and the torque produced by the brake will remain constant.   

A 90-volt brake, a 48-volt brake, and a 24-volt brake would all create the same torque if they were each driven by their corresponding voltages and currents. On the other hand, if you took a 90-volt brake and applied 48 volts to it, you would only get around half of the brake's intended torque output. This is so because torque is almost linearly related to voltage/current. A steady current power source is crucial if you want a brake to deliver precise and maximum torque.   

If an unregulated power source is used, the magnetic flux will deteriorate as the coil's resistance rises. Your torque will decrease as the coil gets hotter.  

Reason for Wear in Electromagnetic Eddy Current Brakes  

It is pretty uncommon for a coil in an electromagnetic brake to suddenly stop functioning when a coil malfunctions, heat is typically at blame since it has destroyed the insulation on the coil wire. High cycle rates, slippage, excessive voltage application, high ambient temperature, and other factors can all contribute to this heat. As long as they are not utilized beyond their ratings, bearings typically have a similar lengthy lifespan.  

The faces of the mating surfaces experience the majority of wear in electromagnetic brakes. A certain quantity of energy is transferred as heat each time a brake is applied while the engine is rotating. Both the armature and the contact surface of the opposing side are worn by the transfer, which takes place during rotation. The speed and inertia wear rates will vary depending on the brake size. When a machine is sped up from 500 rpm with a brake to 1000 rpm, its wear rate is dramatically increased. Simply, your wear rate would double, giving you half the brake's life that you had previously. A brake with a fixed armature design will eventually stop working altogether.  

If you are exploring the market for the best electromagnetic eddy current brake, look no further than BMC Motor!