Abstract: A process and apparatus for preventing the overspeed of a low head hydroelectric generating set including a turbine having an adjustable distributor valve assembly and adjustable vanes wherein the openings of the valve assembly and vanes are continuously monitored relative to one another and with the openings of the valve being limited by a conjugation device so as to insure that the pressure head through the turbine is retained at or just slightly below the normal lowest operating pressure head for which the turbine is designed to operate.

Abstract: A propeller runner having swivelling blades, each integral with a journal engaged in two bearings respectively in the outer portion and the inner portion of the runner, and equipped with lateral connecting rods for manipulation in rotation.The inner central portion of the hub of the runner includes a spider 29 each arm of which consists of a radial journal 31 prolonged by a threaded portion 32. Each blade journal 23 is engaged over a spider journal 31 with a bearing 26 and is held by a nut 33 screwed onto the portion 32 with the interposition of a thrust bearing 30. The spider 29 for a four-bladed runner preferably consists of a core 39 through which passes a shaft 40.The invention is applicable to propeller runners having swivelling blades for turbines.