Design and Development of Three Stator Winding Induction Motor

Three phase induction motors are employed in almost all the industries because of its simple construction and easy operation. Efficiency of the induction motor is affected by its fixed losses and variable losses which mainly depend on the input supply voltage and load current respectively. An attempt is made to minimize the iron losses by controlling the supply voltage. A new Three Winding Induction Motor (TWIM) is proposed in this paper in which stator consists of three windings accommodated in the same core. Stator coils are designed to be operated at 415 V, 350 V and 200 V respectively. Shaft loads are categorized as low medium and high, Stator coils are energized through a controller based on the load demand. In this study, it is suggested to operate the machine with flat efficiency characteristics, irrespective of shaft load. When compared to conventional induction motor slot utility is improved from 29% to 55%. Another approach of this machine is that while one of the windings is considered to meet the mechanical load, as an Induction Alternator (IA) a three phase out put with two different voltage levels are induced in the other two windings. If 415 V winding is considered to meet the mechanical load, a three phase voltage of 350 V and 200 V is induced in the other two windings. These outputs can be used directly or with converters to feed electrical loads or to charge batteries to obtain uninterruptible power supply. Thus, TWIM is operated to its rated capacity and energy conservation is achieved by connecting additional loads in the other two windings. Experiment result ensures the considerable increase in the efficiency and power factor.