Comparison of the torque of cylindrical airgap synchronous couplings versus the magnetization direction of the magnets

The analytical formulas of the tangential and radial component of the force between two permanent magnets, are applied to compare the torque transmitted by permanent-magnet synchronous cylindrical airgap couplings. We have studied three structures of magnetic cylindrical airgap couplings. In the first structure, the magnets have a magnetization direction radial with respect to the rotation axis. This direction is tangential to the rotation axis in the second structure. It is parallel to the rotation axis in the third one, semi analytical method is used to compute the force for this structure. The torque of these couplings are studied and compared with respect to the influence of various parameters such as number of pole pairs, the magnet-width, -length and -depth. (orig.)