ProEV are running a pair of 5134WS20 motors with a pair of Simovert inverters. They have photos of the cooling system and a report that it isn't very effective. They say that at 175C winding temperature, water exits the radiator at 40C and after motors and inverters, returns at only 46C.
Rotor Time Constant
First guess at this value for our motor (1PV5135-4WS28):
T2 = (L1h + L2sig)/R2 With: L1h = magnetizing inductance (H) L2sig = Rotor leakage inductance (H) R2 = Rotor resistance (Ohm) T = L/r = (L1h + L2sig)/R2 =(6mH + 300 uH)/20mOhm =0.315 H/Ohm