All hysteresis machines, are characterised by the use of a ‘hard’ or permanent-magnet material in the rotor of the machine in different forms whilst the stator may be similar to that of a 3-phase induction motor or comprise salient poles. The driving torque in the hysteresis machine is typically related to loss of power resulting from hysteresis in the active part of the rotor. A hysteresis motor which forms the mainstay of a variety of hysteresis machines is a synchronous motor, being self-starting with the developed torque remaining constant throughout. The present book, one of its kind covering the said subject matter, describes in detail the construction and working principle of a variety of commercially available hysteresis machines. The last part of the book is devoted to a comprehensive study of an experimental hysteresis machine. The contents of this part derive entirely from the experimental and analytical work carried out by the author during his doctoral research at the University of Aston in the UK. The exhaustive range of tests and measurements, obtained by the use of uniquely devised transducers and techniques, many of these having been evolved for the first time, showcase numerous aspects of a hysteresis machine, never before brought out anywhere. These relate mainly to the measured waveforms of radial and peripheral flux density in the airgap and active part of the rotor as influenced by the hysteretic properties of the rotor material.