The VLH appears as an almost square-shaped self-supporting mechanically welded structure. It receives the guide vanes, as well as stiffeners. The assembly forms a grid where the spacing between bars is designed to prevent clogging up. The grid profiles ensure the mechanical hold of the bulb containing the generator and the turbine.
Above this grid, a rotating trash rake cleaner clears away the waste by a very low intermittent motion.
Under the rake, the bulb is formed by the turbine runner containing the direct-driven variable-speed permanent-magnet generator. The stator is in central position and the rotor magnets are assembled inside of the turbine runner. The assembly is pressurized. The used compressed air is dried to avoid condensation.
The turbine hub is made of casted iron construction and is provided with 8 blades closing on themselves. Their opening is hydraulically controlled according to the available flow rate and to the instantaneous net head.
The entire self-supporting structure can be taken out of the water for maintenance by rotation around the upper axis of the structure.