Three-phase AC traction drives: design and service experience

The AC induction motor drive has been the subject of wide investigations since the middle of the 1960s. Today it is not only a scheme but a service proven system that is rapidly finding acceptance by more and more transit authorities worldwide. The paper describes the experience with three vehicle fleets with AC propulsion drives which are in service. Strömberg´s AC traction drives have been used over more than 20 million car kilometres and this experience has been a significant source for the development of the newest generation of AC traction drives now being manufactured. The key features of these drives are also described.