Zero-sequence impedance in single-phase induction motor

Abstract

The purpose of this project was to bring to light more facts regarding the zero-sequence impedance in single-phase induction motors. It had been observed in the laboratory that while a three-phase induction motor (wye-connected and neutral available) is running at certain speed, if we change the connections such that power is applied between one line terminal and the neutral, as shown in Fig. 1, the motor continues to run at one-third the previous speed. This is the customary method of measuring the zero-sequence quantities and forms the basis of this project. In the following pages it has been shown that the zero- sequence impedance definitely exists in the stator circuit, as well as in the rotor circuit of a single phase induction motor. The value of the winding pitch is found to affect to certain extent the actual value of the zero-sequence impedance.