Development and performance analysis of a two-phase induction motor in the frame and core of a single-phase induction motor

In this paper, a two-phase induction motor is developed in the core of a single-phase induction motor to run with a two-phase supply. Modification is done by changing the auxiliary winding of the single-phase motor thus giving a constant 90 degree phase difference between main and auxiliary windings being fed through a two-phase voltage source. The two-phase supply is obtained from the conventional three-phase supply by a Scott-T transformer. Scott-T transformer is made of two single-phase transformers with different tapping ratios. Then these two transformers are connected in such a manner which gives two-phase supplies from a three-phase source. The motor is operated in both single-phase and two-phase modes varying the loads in the motor. An electromagnetic dynamometer brake is used for loading purpose in the motor shaft. Load is increased with increasing the DC excitation voltage of the dynamometer and necessary data are collected. The performance of the two-phase mode is analysed and then compared with that of a conventional single-phase mode of induction motor. The developed two-phase mode of operation gives the single-phase induction motor to gain the advantage of starting torque, higher efficiency, less torque harmonics, higher rated power and lower copper loss.