Design and measurement of losses in AC induction motor with different rotor bar material

Abstract

In this thesis, the three phase AC induction motor have been thoroughly investigated and analyzed in terms of the induction motor parameter, efficiency, power factor and loss segregation. Through out this project, a copper rotor bar is fabricated and compared with the existing aluminium rotor bar. The first part of comparison is done with software simulation using Opera 2D between aluminium rotor bar and copper rotor bar for the same 0.5HP stator slot design and winding configuration. The Opera 2D is compared in terms of power loss, magnetic flux density, magnetic field intensity, eddy current density, torque vs. speed, torque vs. slip, power loss vs. speed and power loss vs. slip. The second part is the hardware comparison between the fabricated copper rotor bars with the existing aluminium rotor bar. In this part, the copper rotor bar and aluminium rotor bar are tested using no load, blocked rotor, and DC resistance test to obtain the difference of efficiency, losses and power factor improvement. The load test is also performed to investigate the efficiency of the induction motor at low load factor and result shows that at lower load, the induction motors lose its efficiency and power factor. From the overall experiment of software and hardware, results shows that copper rotor bar does increase the efficiency and power factor to 1% and reduce losses to 5 watts compare to aluminium rotor bar. An economical aspect is presented to show the amount of energy and money that can be saved from replacing the aluminium rotor bar with a copper rotor bar. As for the annual energy saving (AES) and total cost saving (TCS), the copper rotor manage to save 40.32kWh per year and utility billing by RM13.54 per year per motor. Finally a rough estimation of 100,000 pieces induction motor that have been replaced with the copper rotor bars is assumed and shows that it will save approximately RM1.3 million.