Characteristics of a squirrel cage induction motor

This paper investigated the magnetic field distribution in a 1 hp three-phase induction motor. Utilising a triangular finite-element method, the magnetic field in the motor is analysed at various balanced magnetomotive forces and four different rotor positions. From the field solutions, the flux linkages and the slot leakages are found for a range of magnetising currents. An experiment using a straight laminated rotor core without aluminium bars was tested at the four locked positions by using a 20 kVA balanced three-phase transformer with a frequency of 60 Hz. The stator currents, line-to-line voltages and power factors were measured. The experimental data are compared with the calculated results and a reasonable agreement is found. Over a wide range of saturation level, the paper determines parameters such as the magnetising inductance and the core loss resistance in the machine equivalent circuit.