Magnetic rotary couplings are often used by pump manufacturers to isolate a motor from the pump components. The isolation of these components might be desirable for one or more reasons. The fluids in the pump may be corrosive, toxic, under pressure, or sensitive to corrosion from motor lubricants or other materials.
The coupling would typically consist of a pair of multipole magnet rotors interacting across a membrane made from a composite, plastic or metal, depending on the pump application. The performance of these couplings depends on several factors, including:
* Seperation of magnets
* Number of pole pairs
* Membrane material
* Load inertia and acceleration
* Presence of torsional resonance
Membrane materials are sometimes metal alloys, and are therefore conducting. In these cases it is possible to quantify the resulting eddy current losses which will occur, and minimise these by ensuring appropriate choice of material and wall thickness.