Linear machine power requirements and system comparisons

Abstract

The revenue vehicle designs of the two German Maglev groups are analysed and the complex power requirements at the trackside substation calculated. The two systems are the Electromagnetic System (EMS) with either linear induction motor (LIM) or long stator motor propulsion, and the Electrodynamic System (EDS) with linear synchronous motor (LSM) propulsion. The operational conditions considered were 400 and 500 km/h velocities either at steady state cruise or with a grade or headwind additional loading. It is found that the LSM of the EDS system is the most suitable form of propulsion for these operating conditions, the long stator motor for the EMS having apparently reasonable characteristics at 400 km/h, but becoming degraded at 500 km/h, and the LIM's studied being unsuited to the high speed range. These results highlight the necessity to compare not only the active power supplied to a vehicle, but also the complex power at wayside substations to be able to indicate the overall efficiencies and power factors of the competing systems. The German, the Canadian and the Philco-Ford EDS designs are also compared by weight make-up and specific energy intensity. These results show that the advantage gained from a lightweight aircraft-type construction, coupled with the relatively longer body, is lost in the German design because of the extra dead weight of the wheel sets required for running on conventional duo-rail with the resultant heavier body structure. The respective machine power factors are included in the intensity calculations to link in reactive power storage.