Although the basic theory of the noise of electrical machines was elaborated many years ago, the theoretical knowledge has since been considerably extended. This book discusses the acoustics and noise-measuring systems of electrical machines. It is a fully revised English edition of the authors' book published in Hungarian. A detailed analysis is presented of the electromagnetical, mechanical and aerodynamical vibration and noise sources in electrical machines. A summary of the most recent developments in noise pollution is included, as well as the results of the authors' own observations regarding techniques of reducing the noise level of electrical machines and transformers. The vibro-acoustical measuring-technique of machines is discussed generally, both in the steady-state and transient mode of operation. In addition, the noise of transformers and high voltage transmission lines is examined, and the various practical and theoretical methods for noise and vibration reduction are demonstrated. Special attention has been devoted to those chapters dealing with the specific causes of noises generated by modern, electronically controlled machines. With international trade in mind, the book also provides a critical review of international standards on noise and vibration measurements and evaluation, and the newly developed methods currently being introduced. The book will provide both a theoretical and practical background to designers, planners, engineers, scientific workers, students and technicians involved in this field. List of Contributors: P.L. Timár, A. Fazekas, J. Kiss, A. Miklós, S.J. Yang