High head (Turgo Turbine) micro hydro turbines include single phase and three phase units, designed to operate on heads between 10m to 45m with a relatively low flow rate, and the output power between 200w to 30kw. As the name suggests these turbines are designed to be used on sites with an above average head of water and a relatively low flow of water.
The water enters the turbine from the penstock through a nozzle which directs it into a jet and towards the buckets on the turbines runner. The runner is connected via a shaft to the generator which produces a 230v or 380v AC supply. Any excess power generated is diverted to a ¡®dump load¡¯ ballast heating element in the base of the smaller turbines which uses water-cooling to ensure that the load on the turbine remains constant. The larger turbines heating element will be separate and need fixing in place. These machines may be operated for years with minimal maintenance, although it is necessary to apply grease to the bearings using the grease cap a couple of times a month, to ensure a long life.