Modern magnetic materials in permanent magnet synchronous motors

The article discusses the magnetic properties of three magnetic cores dedicated for the 8-poles permanent magnet synchronous motor. These cores have the same geometry of stator and rotor electrical steel sheets but different types of electrical steel are used. In the first magnetic core the standard non-oriented steel type M330-50A is used. In the next two cores modern cobalt-iron alloy electrical sheets type VacoFlux 50 are used. One of these cores has been manufactured without the annealing process, the second one has been annealed according to the manufacturer requirements. On each of three magnetic cores two auxiliary coils had been wound and next the comparative measurements and tests of cores has been performed using them. Basing on the results of these measurements it can be clearly observed that the stator and rotor cores made of cobalt-iron alloy without annealing are not suitable for the building of magnetic circuits in rotating electrical machines. The magnetic properties of cobalt-iron alloy are changed completely after the annealing process, what can be seen in the figures presented in the paper. Magnetic properties of cobalt-iron alloy after annealing process are significantly improved and greatly exceed properties of standard electrical steel sheets.