Topologies for a permanent magnet generator/speed sensor for the ABS on railway freight vehicles

Antilock braking systems (ABS) are being considered for high-speed railway eight vehicles, which since they have no on-board electrical supply, require axle-mounted permanent magnet generators to provide a speed sensing control signal as well as the power for the solenoid valves which control the pneumatic brakes. The authors describe a design study on alternative topologies for such 3-phase generators, and present test results from prototype machines. They then go on to consider the implications of the choice of magnet material and pole number on the design of 'interior magnet' and 'surface-mounted magnet' machine topologies.<>