Magnetic coupling

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As the name implies, this coupling is a synchronous version that inherently results in a 1:1 relationship between the motion of the driver and follower. As taught in grade schools, like magnetic poles (North-North and South-South) repel each other while opposite poles (North-South) attract, synchronous couplings exploit these “attractive” and “repulsive” characteristics to produce motion. By placing an array of alternating pole permanent magnets (N-S-N-S) on the driver and an equivalent array of alternating pole permanent magnets on the follower, a “coupled” magnetic circuit is produced with each North and South pole in the driver linked to each respective South and North pole of the follower. As the driver moves with respect to the follower, the magnet poles start to overlap one another, leading to a “push-pull” effect and consequent motion. The magnitude of the resultant force depends not only on the amount of overlap, but also on the chosen magnetic material’s characteristics and separation distance between the driver and follower. At some displacement, however, the peak force producing capabilities of the coupling are achieved. Displacement beyond this point results in a decoupling. This decoupling manifests itself as a ratcheting action resulting from like magnetic poles is the driver and follower repelling each other. Unlike its mechanical equivalent, however, the decoupling does not, generally, lead to permanent damage; and synchronization is reinitiated at the next magnetic pole coupling point. Pros: Greatest volumetric force density. Cons: Limited to a 1:1 motion ratio Use: Devices that require direct coupling with no slip during operation.