A magnetic coupling is a component which transfers torque from one shaft to another using a magnetic field, rather than a physical mechanical connection. They are also known as magnetic drive couplings, magnetic shaft couplings, or magnetic disc couplings.
Magnetic couplings allow a physical separation between input and output shafts, precluding the use of shaft seals, which eventually wear out and fail from the sliding of two surfaces against each another. Magnetic couplings are also used for ease of maintenance on systems that require precise alignment, since they allow a greater off-axis error between the motor and driven shaft than physical couplings.
Magnetic couplings are most often used for liquid pumps, propeller systems, mine motors, conveyor belt motors and kiln elevators.