The hydrodynamic clutch, also called Foettinger clutch, generally consists of a pump wheel connected to the engine and a clutch-ended turbine that is equipped with uniform, radial vanes. A torque is transferred between the pump wheel and the turbine over a fluid which is accelerated by the pump and decelerated in the turbine (Coriolis effect). The hydrodynamic clutch can partially dissipate thermal losses over the working fluid. Consequently the speed conversion is not limited over time. The figure shows the hydrodynamic clutch in a design without external cooling.