A Magnetic Coupling is a means of transferring torque from one shaft to another without a physical mechanical connection. Magnetic shaft couplings 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 air. Magnetic shaft couplings preclude 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 typically require precision alignment, when physical shaft couplings are used, since they allow a greater off axis error between the motor and driven shaft.
Some diver propulsion vehicles and remotely operated underwater vehicles use magnetic coupling to transfer torque from the electric motor to the prop. Magnetic gearing is also being explored for use in utility scale wind turbines as a means of enhancing reliability. The magnetic coupling has several advantages over a traditional stuffing box.
Some aquarium pumps are Magnetic Drive Pumps -- they use magnetic coupling 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.
A magnetic stirrer is another example of magnetic coupling.
- "Could Magnetic Gears Make Wind Turbines Say Goodbye to Mechanical Gearboxes?". machinedesign.com.
- Eric Stackpole. "Magnetically Coupled Drive"
- "Genesis DPV"
- Dana Riddle. "Making Gadgets for Your Aquarium".