Pelton turbines are impulse machines which produce power using the kinetic energy of high velocity jets impacting on runner buckets. Due to their low specific speeds, their use is generally limited to high head applications. The number of jets may vary from 1 to 6 and each is controlled by a needle valve through a special nozzle. Pelton turbines have a wide operating flow range, with high efficiencies of up to 90% and are always set above the tailwater level.
Deflectors are used at the discharge of the needle valves to partially or wholly divert the jets from the runner during output variations and turbine shutdown. This allows the needle valves to open or close at sufficiently slow rates to minimise pressure waves in a long penstock pipe that are typical of high head sites.
Your Hydro specialises in the manufacture of Pelton turbines in either a vertical or horizontal arrangement, with the turbine runner generally mounted on the generator shaft (i.e. overhung).