| Abstract |
This paper provides a comprehensive analysis and comparison of different rotor bar material insquirrel-cage induction machine from electrical, physical and economic perspectives in order to explorethe impacts of rotor bar material on machine efficiency with physical and economic considerations.Specifically, aluminum, copper and silver are selected in this work and studied on three machines ofdifferent ratings, where silver is proposed as a hypothetical rotor bar material to open discussion and toexplore potential possibilities. To provide an overall analysis, an analytical model and a finite-elementmodel of an induction machine are used in this work with their focus on machine efficiency and magneticflux distribution, respectively. It shows that a silver rotor can provide the highest efficiency under alltested loads and machines with efficiency enhancement of 0.20 to 1.55 percentage points compared to thealuminum counterpart depending on the machine rating and load. Moreover, better performance, such aslarger output power, smaller starting torque, more concentrated magnetic flux distribution, etc., areobserved with the increase of rotor bar conductivity. However, the significantly high price of silver couldimpede its usage in most applications currently and copper rotor bar is believed to have the overallsuperiority among the three kinds of material, although it suffers from casting issues due to its highmelting points. Silver rotor bars or silver alloys may be used in energy-limited areas where highefficiency is needed to compete with certain magnetic material. |
