ABSTRACT
The driving torque in a hysteresis coupling is developed in the driven member by virtue of hysteresis loss in the entire volume of the disc or annulus and depends on the excitation to the field system, but is independent of speed and angular position. The production of torque in the coupling can be explained in terms of variation of radial and peripheral components of flux density in the airgap and arbor as influenced by hysteresis property of the annulus material. The active parts of the coupling are mounted on a rigid platform with the axis of rotation of the field system being vertical. The rotor assembly is held stationary, fitted with a “torque arm”, and is prevented from rotation at any stage for ease of making various measurements. The magnetic field distribution in the machine is modified due to hysteresis property of the rotor annulus material as revealed by hysteresis loops at varying magnetising field or excitation.
