Magnetic gear overload detection and remedial strategies for servo-drive systems

The paper investigates the phenomenon of over-torque pole-slipping when using systems that incorporate magnetic gearboxes and magnetic couplings. When subjected to a transient torque overload, a magnetic gear/coupling enters a pole-slipping regime with consequential loss of control and complete failure of power transfer between the prime-mover (motor) and load. Techniques are proposed for the rapid detection of a pole-slipping condition using only motor-side measured variables. On detection of a pole-slipping (fault) condition a reconfigurable controller re-engages the load-side of the magnetic gear, restoring power transfer to the drive train.