Stablity and Control of the Speed of a Hydroviscous Drive

A hydroviscous drive is a new type of power transmission device utilizing the viscous shear of the oil film between two sets of discs. It has used widely for speed regulation and energy saving in large fans and pumps . As a new type of transmission technique its stability and control of speed is one of the most important research programs . According to the basic theory of fluid friction the dynamic mathematical model is devebped and the output transfer function derived by means of the linearization process . With the Routh Criterion for stabilty on modern control theory the stablity and the stable working range of its output speed is analysed and researchedon. It is proved in theory that the stability of speed can be increased and the stable working range can be expanded by the closed loop feedback control of the speed .At the end of the paper the influence of various parameters on the stable working range is discussed .The result of this paper is proved correct by experiments and being applied successfully in industry .