Production of low impurity aluminium rotor for motor efficiency enhancement

Abstract

Abstract. Induction motors have been widely used in various electrical applications. However, their efficiency are still limited due to losses occurring during operation,especially for smaller ratings. Higher the electrical conductivity of motor rotor by lower its impurity content is one of practical and simple way to improve motor efficiency. The aim of this work is to reduce the impurity content of aluminium rotor by addition of boron in the form of Al-5wt%B master alloy and Na2B4O7-NaCl-KCl flux, and then sedimention of their precipitated particles. The purer melt was then cast as rotors for single-phase induction motors. With the amount of addition of boron in aluminium melt in this work, boron in Al-5wt%B master alloy was more pronounced in removing impurities in aluminium melt than that in Na2B4O7. It was found that the rotors made of aluminium melt with lower impurity contents and hence higher electrical conductivity resulted in more enhancement of motor efficiency.

Advances in Metal Casting Technology: A Review of State of the Art, Challenges and Trends—Part II: Technologies New and Revived

“…Here, a link to e-mobility applications, as discussed in Part I of this work, is apparent, e.g., in rotor casting [1]. Classical rotor aluminum Al99.7 is almost pure and characterized by limited castability; nevertheless, it is employed in HPDC to produce electrical engine components [55]. Alternatives include low alloyed materials such as AlMn1.6, as, e.g., offered by Rheinfelden, which do pose similar castability problems but add strength, increasing yield strength from Al99.7's 20-40 MPa to 90-120 MPa [56].…”