The ultrasonic motor, invented in 1980, utilizes the piezoelectric effect in the ultrasonic frequency range to provide the motive force. (In conventional electric motors the motive force is electromagnetic). The result is a motor with unusually good low-speed high-torque and power-to-weight characteristics. It has already found applications in camera autofocus mechanisms, medical equipment subject to high magnetic fields, and motorized car accessories. Its applications will increase as designers become more familiar with its unique characteristics.

This book is the result of a collaboration between the inventor and an expert in conventional electric motors: the result is an introduction to the general theory presented in a way that links it to conventional motor theory. It will be invaluable both to motor designers and to those who design with and use electric motors as an introduction to this important new invention.

From reviews of the first edition:-

".... quality and qulaity of illustrations is noteworthy... a comprehensive and thought provoking summary of stepping motor technology. Times Higher Education Supplement.

A general textbook on the use of stepping motors ... a comprehensive guide to the subject. Electronics and Power.

Whenever repeated stop-start or incremental controlled motions are encountered, there are apllications for stepping motors. Their basic design and constructure make them enimently suitable for digital (microprocessor) control and they are consequently found in computer hardware- disk drives, printers, etc, in clocks, in numerically controlled machine books, and in domestic appliances.

In this successful textbook, the authors take a practical approach to stepping motors, using many informative diagrams to explain their working principles, construction details, electronic controls, applications, and methods of maufacutre.

This book covers microprocessor-controlled power electronic drives, focusing in particular on the controol and use of low- and medium-power motors. Such drives have applications in the motion control of robots, computer peripherals, and numerically controlled machines.