IntroductionA magnetic bearing is a type of bearing that supports a load using magnetic levitation. Scientists first discovered magnetic effects in magnetic minerals in 500 BC. At the end of the 20th century, scientists began to develop ways in which this magnetic effect could be implemented in a bearing, creating magnetic bearings. Today, magnetic bearings can be found in many applications where no physical contact is required or where extreme environmental conditions exist, including very high and low temperatures. Magnetic bearings also offer higher operating speeds, efficiency, longer machine life, and lower operation and maintenance costs as they are virtually maintenance-free. Overview of Active and Passive Magnetic Bearings Magnetic bearings can be divided into two different categories depending on the type of application that will be implemented in: passive magnetic bearings and active magnetic bearings. Passive magnetic bearings use permanent magnets, which allow the shaft to maintain position through the center of the bearing without the necessary use of input electrical energy. These permanent magnets are placed inside the cylindrical bearing to ensure that the shaft levitates freely without the aid of surface friction. The advantage is that these magnets are able to keep the tree in balance without the aid of external electricity. The problem that passive magnetic bearings face is that it is very difficult to design these types of permanent magnetic bearings due to the limitations of the actual permanent magnet. The limitations are that, since there is no need for external electricity in a permanent magnet, the actual lack of it makes it difficult to create an assembly of point charges that build... in the center of the paper... of bearings is the size of the actual bearing and the space the bearing must occupy in the specific application. This can create conflict if you need to mount a bearing in a very small or large location. What are the dimensional limits of magnetic bearings? As of now, there is no upper limit to the size of a magnetic pad. However, you may encounter some design disparities when creating such large bearings. Many times the bearing must be separated into two halves or the magnets must be treated individually. Progress has also been made in the field of nanotechnology for bearings. These bearings are needed in the medical field, for hard drives, video heads and optical scanners. For example, there is a micromotor that uses a bearing suspended at the millimeter level. This motor has an external diameter of just 1.5 mm and has been used at speeds up to 600 rpm.