Abstract: A self-illuminating coaxial knob provided on an operating panel of an air conditioning apparatus, an acoustic apparatus or the like, in which an outer knob and an inner knob connected to an outer shaft and an inner shaft, respectively, are coaxially provided on a panel surface, the panel being provided with a graduation, and the knobs being provided with indexes, respectively. The outer knob is illuminated from the back by a panel surface illuminating portion circularly provided on a panel surface light guide, whereas the inner knob is illuminated by a ring-like inner knob light guide provided in a ring-like incoming portion.

Abstract: A hydroelectric power generator having a bulb turbine generator housed in a bulb shaped inner casing. The turbine runner of the generator is connected to a main shaft of the electric power generator. The outer casing is coupled to the inner casing by stay vanes. A draft tube is coupled to the downstream end of the outer casing. A liftable gate is positioned to retain water in the open channel and the outer casing is fixedly secured to the gate and vertically movable with it.

Abstract: A hydraulic power plant has a reservoir with a dam wall, a water turbine connected to a generator, a penstock extending from the reservoir to the water turbine and passing over the dam wall without passing through the dam wall to supply water from the reservoir to the turbine, and a vacuum pump adapted to fill at least a portion of the penstock with water by a siphon effect and being connected at a substantially uppermost portion of the penstock which is located on the top of the dam wall.

Abstract: An apparatus for controlling a water turbine is disclosed wherein an auxiliary servomotor having a capacity substantially equal to that of a servomotor for actuating pressure regulator is provided for actuating flow control guide vanes, the auxiliary servomotor for the guide vanes and the servomotor for the pressure regulator being connected through pipe lines. The guide vanes for the water turbine are controlled according to a position of an auxiliary servomotor for the governor and the servomotor for the pressure regulator is controlled according to a difference between the opening position of the guide vanes and the set position of a load limiter for the water turbine.