Double regulated Francis turbine

Double regulated Francis turbine

With the double regulated, variable speed Francis turbine, speed optimisation by means of a frequency converter leads to a considerable increase in efficiency as well as an increase in the annual working hours and that, without any structural intervention during conversion. In addition, the efficiency is significantly improved in the partial load range.

Benefits and advantages

  • Increased efficiency of the Francis turbine through speed optimization using frequency converters.
  • Increase of the annual working hours.
  • Efficiency improvement in the partial load range.
  • Easy to retrofit, as no structural interventions are required.
  • Increased performance (EEG compensation).


(Left picture: retrofitted frequency converter)

Research project at the Silbersee power plant

Together with the Bayerische Landeskraftwerke GmbH and AMServ as well as the Ostbayerische Technische Hochschule Amberg-Weiden and the engineering office Pfeffer, an interesting cooperation project was developed at the Silbersee power plant in Tiefenbach.

The previous simple Francis spiral turbine will be retrofitted with an intermediate electronic frequency converter. This allows the speed of the turbine to be changed. The efficiency increases significantly without affecting the frequency of the connected power grid. The originally single regulated turbine becomes a double regulated Francis turbine.

The tests carried out with different load profiles are evaluated in detail. Many other operators as well as Bayerische Landeskraftwerke GmbH benefit from the positive result.

Besides F.EE, the Ingenieurbüro Pfeffer, the Bayerische Landeskraftwerke, the AMServ GmbH and the Technical University of Applied Sciences Amberg-Weiden are involved in the research project.


  • Long-lived and reliable technology
  • Innovative operation thanks to fe.screen-view

Control cabinet construction

All hydropower control cabinets are produced in our own production centre in Neunburg v. W.

To control cabinet construction

Mitarbeiter Schaltschrankverdrahtung

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