One of the major problems associated with the design and application of active magnetic bearings is excessive heat. Heat is generated by two main mechanisms. The first source of heat comes from eddy current losses. Eddy currents are electric currents driven in conductors by a dynamic magnetic field located in the conductor. Eddy current losses in a magnetic bearing are caused by the rate of change of the magnetic field. The relative motion creates a rotating current flow inside the conductor, resulting in a loss of efficiency. The second source of heat comes from the resistance of the wires in the coils. Since copper wires have a resistivity that increases with temperature, heating can become extremely rapid if there is no way to release the excess heat. Excessive heat from a magnetic bearing can even be caused by lack of lubrication. Although lubrication-free operation of a magnetic bearing guarantees a wear-free system, nothing can now cool the bearing. Heat buildup can create many serious problems, such as destroying magnetic bearings by breaking down the coil insulation and causing short circuits. Excessive heat can also result in the inability to support the desired load in the application. Another significant problem produced by magnetic bearings is the limited fault protection. Machines equipped with magnetic bearings always install a set of backup bearings, which are usually rolling element bearings. These backup bearings can produce their own set of problems. The installation of emergency bearings can modify the dynamic behavior of the machine rotor. Backup bearings also have a very limited lifespan. When a magnetic bearing fails, the backup bearing must catch up to the rotor in as little as a millisecond. Generally...... middle of paper ......ing, the inadequate direct rigidity of... was also once mentioned. Low forward stiffness in a bearing occurs when clearance is increased to accommodate conventional relief bearings. This causes the magnetic bearings to provide a large surface area to be able to support a moderate load. (Add innovation to low direct stiffness) ConclusionMagnetic bearings have provided us with new ways and innovations to operate various systems such as space equipment and energy storage systems. Magnetic bearings have allowed users to operate systems unlike any other bearing system. They have implemented a lubrication and maintenance free system, which in turn provides a much cheaper and fault free system. Although magnetic bearings are not perfect and are limited in specific areas, we believe they have the potential to revolutionize the field of mechanical power transmission..