Optimizing the Axial Length of the Slitted Solid Iron Rotor

The effect of the axial length of the solid-rotor on the performance of the induction machine is experimentally studied. Initially, the rotor has 60 mm long "end rings" of solid steel. During the measurement procedure the length of the rotor end iron is shortened from 60 mm to 0 mm and, finally, the rotor length is equal to the stator stack length. It was found that in order to improve the torque production ability and the efficiency of the solid-rotor induction motor the length of the solid-rotor end iron should be as short as possible. It is shown that the effect of the solid-rotor end iron length on the solid-rotor motor efficiency can be as high as 1.5 per cent in a case of a 180 kW, 10200 rpm machine.