Effect of rotor pole-shoe construction on losses of inverter-fed synchronous motors

The effect of rotor pole-shoe construction on the electromagnetic losses of frequency-converter fed wound-field synchronous motors is studied by numerical simulations. In the machine under examination, a reduction of 6.8 % in the rated-load total electromagnetic losses was achieved merely by modifying the rotor pole-shoe shape and the damper winding slots. Furthermore, a 15.4 % reduction was achieved by removing the damper winding and changing the rotor lamination material to a 0.5-mm Fe-Si sheet instead of the original 2-mm steel sheet.