A magnetic bearing is a type of bearing which uses magnetic field to employ magnetic levitation or magnetic suspension to support loads. This implies they extend assistance to moving parts without any physical contact and withstand the loads. This also means that the amount of friction generated is very less or negligible and there is zero mechanical wear and tear. There is no limit for maximum speeds and they can support very high speeds. There are different components in magnetic bearing system, namely, an electromagnet, a sensor, a rotor, an amplifier and a controller; each of these having their respective responsibilities towards the well-functioning of the entire bearing system and failure of either one of these components will result in malfunctioning of the bearing.
There are two types of magnetic bearings namely, active magnetic bearings and passive magnetic bearings. The passive magnetic bearings do not need any external power input arrangements as they make use of permanent magnets for their operations. But most magnetic bearings are typically active magnetic bearings which use electromagnets and hence need a continuous external input of power along with an external controlling system in order to regulate the load and maintain stability. The oil lubricated bearings are being replaced by the active magnetic bearings. There are applications which need combination of these types; in which the permanent magnetic bearings withstand the static load and the active magnetic bearings come into action when the floated object diverges from the ideal position.
The magnetic bearings have different types depending upon the control action (Passive, Active and hybrid), the supported load (Radial or journal, radial or thrust and conical), forcing action (attractive and repulsive), magnetic effect (electro dynamic and electromagnetic), applications (linear motors, levitated rotors, contactless gear trains etc.) and the sensing action (self-sensing and sensor sensing). The material used for the magnetic bearings are iron, neodymium, cobalt, boron, samarium, aluminium, ferrite and nickel. They are chosen based on the applications. However, there are certain issues with respect to the material used – such as material brittleness, operating temperatures which might affect the material causing failure of the system and varying space requirements which are essential for carrying out the procedure smoothly.
Magnetic Bearings Market: Applications
Magnetic bearings are used in various industries such as bio-medical engineering, semiconductor industry, maglev transportation, precision engineering, aerospace, turbo machines, vacuum technology and structural isolation. Magnetic bearings are vividly used in compressors, pumps, generators, turbines and motors. They are widely used in watt-hour meters, in high precision equipment, used to support instruments in vacuum (example: flywheel energy storage systems), used in certain centrifugal compressors, used in artificial hearts, used in various ventricular assisting devices (Life flow heart pump uses magnetic bearings), used in turbo molecular pumps, active magnetic dampers, turbo machines, smart aero engines, high precision position stages, blood pumps, variable speed spindles, elastic rotor control, pipeline compressors and used in gears, conveyors, chains, etc.
Magnetic Bearings Market: Growth Drivers
Magnetic bearings have several advantages such as they are not affected by wear (as there is no contact, wear does not take place), show less friction coefficient, can bear irregularities automatically with respect to mass distribution, allow the rotors to spin around their central axis with negligible vibrations, magnetic bearings are widely accepted in ventricular assist devices as they facilitate reduction of high shear stress areas and reduce flow stagnation in blood pumps. These advantages are strong factors for the growing adoption of the magnetic bearings in various applications, thereby contributing to the growth of the magnetic bearings market.
Moreover, facts such as reliability, practicability in usage, working with high speeds conveniently, absence of external lubrication, less maintenance costs due to absence of wear, robustness to external turbulences, isolation of vibrations making process smoother and facilitating longer system life owing to better durability add to the acceptance of the magnetic bearings in different industrial domains and growth of these bearings in the world market.
Magnetic Bearings Market: Challenges
There are certain challenges that the magnetic bearings market face. Factors such as high initial instalment costs, losses involved such as air losses, iron losses and copper losses and they need external backup gearing system in case of power drop and system failure.
Magnetic Bearings Market: Developments
Technological advancement has made it possible to use an induction based system for levitation (for example: the Inductrack system), it is conceivable that the magnetic bearings can easily replace complex control systems by using simple closed loop coils and by using Halbach Arrays. For systems that are rotating a homopolar magnet design can be used replacing the multipole Halbach designs, thereby facilitating reduction in losses at a considerable rate.
Electrodynamic bearing system which is homopolar has been developed which is built on passive magnetic technology, does not need additional controlling electronic systems for operation owing to the generation of a restoring force due to electrical currents produced by motion. The innovations related to integration, miniaturization and standardisation are increasing the acceptance of magnetic bearings for newer applications as well and redefining standards for smaller and better processes.
Magnetic Bearings Market: Key Companies
The key companies in the magnetic bearings market are Synchrony Magnetic Bearings, Calnetix Technologies, Waukesha Magnetic Bearings and S2M.