Thermal design of a permanent magnet motor used for gearless railway traction

The thermal calculation of a 500 kW permanent magnet (PM) motor with surface mounted rotor magnets used for gearless traction in railway applications is discussed. The motor features a water jacket cooling. A 3D time-stepping finite element method (FEM) thermal model in ANSYS is used. The model is parameterized for optimization of the motor thermal utilization. Fault situations are also investigated using a transient calculation. Thermal measurements with a 500 kW prototype motor, performed on a test-rig, are in good concordance with the numerical results.