Design Strategies and Different Materials for High Efficiency Induction Motors. A Comparison

The paper presents the results of a research project concerning the efficiency improvement in in-dustrial three-phase induction motors, making use of three different design strategies: substitution of copper cage for aluminium cage with standard and “premium” electrical steel; design optimisa-tion of copper cage motor by changing the stator winding and the stack length only; design optimi-sation of copper cage motor by changing the stator winding, the stack length and the stator and rotor slot shapes. The aim of the project was the analysis and the construction of several prototypes of induction motors by using the above mentioned innovative technological solutions, in order: to compare the design strategies; to verify the actual efficiency improvements, the arrangement of the motors with respect to the European Classification Scheme (EC/CEMEP), the contribution of each material and innovative technology to the efficiency improvements. The paper presents the results related to above mentioned design strategies, and concerns a typi-cal 3 kW, 4 pole, 50 Hz, 400 V, TEFC induction motor. The experimental results presented in the paper refer to the Standard CSA C390-98.