Water and the mill

To keep working, water is essential to every mill. Purchasing water from a watercourse has always been guaranteed by so-called water right. Every mill, but also a saw mill, a horse gear or an iron-mill is obligated to use the water according to this right. At our millhouse the water is run to the mill in a raceway to a reservoir. Then it goes to a concrete shaft with an inbuilt turbine (until 1942 it went to a trunk and a water wheel). The water that runs through the turbine then flows back to the Radotín Creek. Our mill operated with a water wheel powered by “overhead” water for centuries. The last one was 4,8m in diameter, there were 64 buckets which were 87cm in width and their radial depth was 23cm. The rims were 9 cm thick and 26cm in width. The wheel made 5 revolutions per a minute. It operated from 1923 to 1942. In that year it was replaced with a Francis turbine with a horizontal shaft by the Prague company J. Kohout and in year1943 also dynamo. The direct current gained was mainly used for lighting the millhouse. However, the whole mill remained out of order between 1951 and 1992. We intended to perform a complete reconstruction of the turbine and to replace the original dynamo with a three-phase generator in order to produce electric power (alternating current) already in 1992. Unfortunately, we were able to accomplish the task of the overall restoration only in 2008. It is small, but it pleases us.

Some technical parameters of a small hydraulic power plant:
A Francis turbine with a horizontal shaft in a concrete fountain consists of a 390mm in diameter circular wheel with 9 embedded blades. The other main part is the gear wheel with shifting adjustment blades. The maximum opening of the wheel is chosen so that with an effective gradient of 5,9m the amount of water running through the turbine is 160 l/sec maximum. An asynchronous 7,5kW motor with 960revs/min (by MEZ Mohelnice comp.) is used as a generator. The gear wheel is operated by a hydraulic plant and everything is powered by an electric unit.

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