Böcker av Fathe Allythi

There no any doubt that, the science of electric machinery is one of the necessary important sciences for the undergraduate students in electrical engineering and in mechanical engineering as well. This book "Single Phase & Special Electric Machinery" covers single-phase and most of special electric machines. Single phase motors are those to be fed from single-phase supply. Although they are less efficient when compared to 3-phase motors, they are the most familiar in use for home appliances, shops, offices etc. This is because 3-phase power was originally generated and distributed for lighting only; millions of homes were given single phase supply. Even where 3-phase mains are present, single-phase supply may be obtained from it by using one of the three lines and the neutral. On the other hand, special electric machines are those used to perform special domestic. Some of them machines find applications in computer peripheral equipment or in process control systems whereas others can be used in devices such as home appliances.

Three phase induction motor is one of ac machines family. It converts the ac electrical power input into a mechanical power output. The conversion process takes place through the rotating magnetic field. Its theory of operation is based on the mutual electromagnetic induction between the primary circuit and secondary circuit. Three-phase induction motors are the most widely used electric motors in industry. When fed from constant voltage constant frequency they run at nearly constant speed from no-load to full-load. 3-phase induction motors are simple, rugged, low-priced, easy to maintain and can be manufactured with characteristics to suit most industrial requirements. Nowadays, with the development of power semiconductors, induction motors may be considered as serious rivals to dc motors in many speed control systems.