Coupling magnetic are most often used for liquid pumps and propeller systems since a static, physical barrier can be placed between the two shafts to separate the fluid from the motor operating in the air. Coupling magnetic preclude the use of shaft seals, which eventually wear out and fail from the sliding of two surfaces against each other. Coupling magnetic are also used for ease of maintenance on systems that typically require precision alignment when physical shaft coupling magnetic are used since they allow a greater off-axis error between the motor and drive shaft.

Applications

Some diver propulsion vehicles and remotely operated underwater vehicles use magnetic coupling to transfer torque from the electric motor to the prop. Coupling Magnetic gearing is also being explored for use in utility-scale wind turbines as a means of enhancing reliability.The coupling magnetic has several advantages over a traditional stuffing box.

Some aquarium pumps are coupling magnetic drive pumps— they use coupling magnetic between the motor on the dry side of an aquarium wall and the propeller/impeller in the water on the other side of that aquarium wall. With two face-to-face magnetized disks — one driving magnet on the dry side and another driven magnet on the wet side of the glass — there are two options for designing the magnetic pattern on each disk. One option balances the (attractive) section that transfers torque, with coupling magnetic repulsion near the axis, to nearly cancel out axial load. The other option designs the coupling magnetic pattern to maximize the torque and uses a mechanical thrust bearing to resist the attraction between the magnetized disks. A magnetic stirrer is another example of coupling magnetic.