Book excerpt: The book is designed to cover the study of electro-mechanical energy converters in all relevant aspects, and also to acquaint oneself of a single treatment for all types of machines for modelling and analysis. The book starts with the general concepts of energy conversion and basic circuit elements, followed by a review of the mathematical tools. The discussion goes on to introduce the concepts of energy storage in magnetic field, electrical circuits used in rotary electro-mechanical devices and three-phase systems with their transformation. The book, further, makes the reader familiar with the modern aspects of analysis of machines like transient and dynamic operation of machines, asymmetrical and unbalanced operation of poly-phase induction machines, and finally gives a brief exposure to space phasor concepts.