Analysis of Materials Used in the Construction of Electric Motors

The paper presents the evolution of electric motors from the point of view of the materials used. Magnetic materials and composite materials, which are used in the construction of electrical machines, are analysed. Composite materials based on magnetic materials have a large coercive field, a wider hysteresis cycle, they cannot be easily demagnetized and they absorb better the vibration energy - therefore the noise is reduced. In the design of electric machines, the aim is to obtain a higher magnetic permeability across the frequency spectrum and to reduce the losses in iron and copper. We analysed the radial electric motors with cylindrical magnets, electric motors in discoidal form with axial field and motors with magnets with transverse flux. Hard magnetic materials were presented and the advantage of their use was highlighted - they retain a significant residual magnetization which translates into a significant saturation magnetization. The synthesis of Fe nanoparticles is performed and the composite materials obtained from iron powders with organic or inorganic binders are analysed with the purpose of reducing iron losses in electric motors.