an Omega Megasonic wristwatch have no teeth; instead, magnetic north and south poles on neighboring gears act like the teeth and trough of spur gears, allowing each gear to drive the next gear in the chain. Such magnetic gears, like spur gears, always have gear ratios consisting of small integers. More sophisticated magnetic gearing uses pole pieces to modulate the magnetic field; they can be designed to have gear ratios from 1.01:1 to 1000:1. Applications (As a single product) Magnetic couplings are used in many industrial application involving rotational power. It is an alternative to fluid couplings Features Magnetic couplings have some notable properties: No vibration Because there is no contact between the active part and the driven part of a magnetic coupling, and there is no rigid connection problem. Sudden changes and vibrations are not directly transferred across the coupling. Therefore, it can avoid the transmission of vibration, resulting in smoother mechanical operation. Overload protection Magnetic couplings offer protection against overload during operation. If the load on the driven component becomes too large, the two parts may slip out of sync and end the transmission of torque. This avoids damage to the system, protecting both the motor from excessive loads and the driven component from deformation. Easy maintenance A magnetic coupling transmission device is relatively simple in structure, and there is a gap between the driving part and the driven part, which is easy to install, disassemble, troubleshoot, and maintain. Easy power transmission Magnetic couplings can transmit power via a linear motion, rotary motion, or helical compound motion (a combination of linear motion and rotary motion). The combination of these transmission methods and different mechanical geometry can realize a wide variety of orderly motion in three-dimensional space. Safety Because magnetic couplings do not penetrate the surface they operate across, pumps that use this type of coupling can completely avoid leakage. This is particularly important if the pumped fluid or gas is corrosive, toxic, flammable, explosive, acidic, alkaline, or otherwise harmful. This makes magnetic coupling transmission technology especially applicable in the production of petroleum, chemicals, and pharmaceuticals, and in the industries of offshore oil well operations, non-ferrous metal smelting, wet mineral processing, and food processing. See also Electromagnetic clutch Magnetic particle clutch References Magnetic devices Rotating shaft couplings