Hydro Electric Turbine Generator The Mel500 is a low head propeller (turbine). Consisting of a rotor assembly, main casing, forward and aft draft tubes and an isolating valve. The rotor assembly consists of 4 adjustable blades which can be adjusted to ensure maximum efficiency and operating speed as head and flow rates vary. The drive shaft comes out of the main casing through a set of seals and driving the alternator/generator by v-belt and pulley to give the required speed. The forward draft tube has a series of guide vanes that will impart a twist into the water flow prior to the flow impacting the blades. The isolating valve allows flow to be shut off during maintenance periods.