Development of electrical machine with magnets and cores obtained by powder metallurgy

Abstract

The aim of this work was the development (design, construction and tests) of a Three-phase Synchronous Machine with permanent magnets and four poles to be used in small wind turbines, where the rotor and stator cores, usually constructed from laminated steel sheets, were replaced for massive blocks obtained from the Powder Metallurgy (PM) process. The other parts of the machine, such as housing, shaft, bearings and covers, were obtained from conventional three-phase induction motor of 10 HP. Initially, it was studied sintered alloys from pure iron, Fe-Si, Fe-P and Fe-Ni; eventually these alloys were analyzed in terms of magnetic and mechanical properties as well as electrical resistivity. From this study, it was chosen the use of sintered pure iron for the construction of the rotor and Fe1%P for the construction of the stator. The permanent magnets used were Nd-Fe-B, and the windings calculation was based on the coiling of the three-phase induction motor. According to the tests performed, it was observed the generation of a three-phase sinusoidal wave voltage of 242 VRMS, and the yield of 40.8%.