Materials for lightweight electric motors- A review

Abstract

Electric motors are widely used in automobiles and large electric vehicles would be introduced in market in the near future to reduce global warming. Reduction in electric motor weight also reduces the overall weight of automobiles. The use of fiber-reinforced polymer materials reduces the weight of electric motors. Lightweight electric motors promote energy savings owing to the reduction of self-weight. Researchers all over the World are trying to make all parts of electric motors using lightweight materials. This review paper presents the outcome of research carried out by researchers from Germany and UK. Fiber reinforced plastics (FRP) reduce weight and increase mechanical and electrical properties. Phenolic composite materials gave promising results due to its electrical insulation properties and corrosion resistance. Thermosets do not swell when they are exposed to chemicals unlike thermoplastics. Aluminium matrix composites (AMC) are used to improve the motor efficiency resulting in a considerable weight reduction. Electric motors have 90 percent or above, which means that a high mechanical energy is derived from electrical energy. The remaining electrical energy is converted into heat. To prevent overheating, the heat is conducted through housing to a cooling jacket having cold water. Researchers have replaced the circular wire by rectangular flat wire that can be coiled tightly on the stator. Newer cooling concepts are developed for making housings using polymer materials. Carbon fiber reinforced materials with metal pins are used for reducing weight and to increase thermal conductivity. Use of high modulus fibers increase damping properties and reduce noise produced by electric motors. Comparisons between electric motors made of lightweight materials and traditional metals in terms of weight, efficiency, cooling rate are presented.