PERFORMANCE OF A FRACTIONAL DC ELECTRIC MOTOR EQUIPPED WITH PLASTIC BONDED ND2FE14B STATOR POLES

Injection molding Nd2Fe14B plastic bonded magnetic material is pressed into the form of cylindrical ring segments in order to investigate it s performance when used in the manufacturing of stator poles of fracti onal power de motors. Measurements of speed and armature current versu s different load torques were performed. The experimental results obta ined for stator poles made by three plastic bonded Nd2Fe14B magnetic m aterials of different densities, are compared to those results obtaine d by using a pair of typical barium ferrite stator poles. The torque v ersus speed curves, the obtained mechanical power versus speed and the efficiency of the motor as a function of the speed are presented. The torque speed data in high speeds follow a linear law, as is expected by theory, while at low speeds, below a crossover point, a deviation f rom this linearity appears. This is attributed to temperature effects. In this work it is shown that in the region of light loads and high s peeds, at a certain speed, the injection molded Nd2Fe14B permanent mag net stators produce a higher electromagnetic torque, higher mechanical power, and higher efficiency than the barium ferrite ones. (C) 1997 A merican Institute of Physics.