I suspect heat is a limiting factor here. Also, if the vanes of the rotor are spinning _in_ the fluid, doesn't this also make it a torque converter? If so, th

I suspect heat is a limiting factor here. Also, if the vanes of the rotor are spinning _in_ the fluid, doesn't this also make it a torque converter? If so, then suddenly stopping the motor could be catastrophic depending on how much kinetic energy is in the system at the time.