Commonly used electromechanical energy conversion apparatus, and equipment that transform electrical energy from one voltage to another voltage may be classified as Common Electrical Machines. Accordingly, Transformers, Synchronous Generators, Three-phase Induction Motors, Single-phase Induction Motors, Single-phase Series Motors and dc Series Motors come under the category of Common Electrical Machines. Transformers are used in electric power systems, in industries, in electric traction, for electric welding, in electric furnaces, for high-voltage testing, in power electronic devices et cetera. Machines generating single-phase and three-phase power are called single-phase and three-phase synchronous generators respectively. Standby generators of low power rating used during failure of the power supply are generally of single-phase type. Large generators supplying bulk power invariably have three phases. This is because generation, transmission and utilization of three-phase power are economical and more efficient. Generators used in ships are of variable frequency so that the speed of the motors driving...