Induction motor with pole-changing winding for variable supply frequency

For induction drives that are operated at two speeds the approved Dahlander technology with pole changeable coils in the stator of the motor can be applied. Being operated at constant supply frequency the motor with Dahlander coils can be driven at a speed ratio of 2:1 without using a frequency converter. The advantages are the simplicity and the robustness of the machine as well as the saving of weight and installation space due to the omitted power electronic circuits, although the motor and its pole changeable coils have to be designed with particular care. While the Dahlander winding for single frequency operation has often been made subject of discussion, this paper presents the approach of an induction machine with pole-changing coils operating on mains supply with variable frequency for aircraft application. Measurements on a prototype of the machine show that the required performance for the use as a pump drive is achieved properly.