ABSTRACT
In Chapter 4, we studied the polyphase AC induction machine, with emphasis on its application as a motor. For some applications, the system speed is not critical; however for many others, it is necessary to control the running speed and dynamic performance of the system. We now turn our attention to the issue of speed control of AC motors. Even though we have considered only one type of AC machine, the issues we shall discuss are generally applicable to all AC devices, and we use the polyphase AC induction motor as a major application of these principles.
