Transient Performance of Hysteresis Motors with Ferrite Magnets

Abstract This paper presents a general picture of basic features of the transient performance of circumferential-flux hysteresis motors when ferrite magnets (Ceramic–8) are oriented within the rotor. Based on the parallelogram approximation of the B-H loops of the magnetic materials, a mathematical model to predict the transient performance of such motors is given. This simple analysis is used in demonstrating various features of transient characteristics including the effects of load, magnet strength and supply voltage on the starting run-up. An important aspects of the asynchronous performance of this type of motor using the pseudo-constant-speed approach are investigated. The motor was tested with and without ferrite magnets, both the cases are compared together, to serve as a guide to both the designer and the user of this type of motor. A reasonably close agreement between the measured and calculated values is obtained.