Coaxial Hydroturbine

an axial-flow hydroturbine with two rotors, one of which is mounted on a hollow shaft through which passes the shaft of the second rotor. The rotor shafts, which turn in opposite directions, may be coupled to the rotor shafts of two generators positioned one behind the other or to the shafts of a rotor and a counterrotor (seeCOUNTERROTOR UNIT). In a coaxial hydroturbine the flow is fed from the intake successively through the rotors and then to the suction pipe. Because coaxial hydroturbines are considerably more complicated than adjustable-blade and mixed-flow hydroturbines, they have not been used in hydraulic power plants.