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HM 365.31 Pelton and Francis Turbine
Education / GUNT Hamburg / Fluid Mechanics and Hydrology / Hydraulic Fluid Energy Machines /

Water turbines are turbomachines utilising water power. They convert pressure and flow energy into mechanical energy and mostly are used for driving electrical generators. Water turbines can be divided into impulse and reaction turbines depending on their operating principle.

  The HM 365.31 accessories contain a Pelton turbine as an example for an impulse turbine and a Francis turbine as an example for a reaction turbine. The two turbine types are examined and compared with each other together with the HM 365.32Turbine Supply Unit and the HM 365 Universal Drive and Brake Unit. The drive unit offers the possibility to set constant speeds resp. torques. Thus you can realise experiments in different realistic operating modes.

  The Pelton turbine is a free-jet turbine which converts the pressure energy of the water into kinetic energy entirely in the control device. As the complete pressure difference is reduced exclusively in the nozzle, the pressure is constant in the impeller. The turbine is also known as a constant pressure turbine. The turbine power is controlled by adjusting the nozzle cross-section.

  The Francis turbine converts the pressure energy of the water into kinetic energy in the control device and in the impeller. The pressure at the wheel inlet is higher than at the wheel outlet. The turbine power is controlled by adjusting the vanes in the control device.

   HM 365.32 provides the water supply, the pressure measurement at the turbine inlet and the flow rate measurement. In order to measure the pressure at the turbine outlet, the Francis turbine is

equipped with an additional pressure sensor. The HM 365 Universal Brake and Drive Unit measures the braking torque and the speed.

  The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments.


Learning Objectives / Experiments

In combination with the HM 365 Universal Brake and Drive Unit and the HM 365.32Turbine Supply Unit
- Comparison of impulse and reaction turbines
- Determination of the mechanical and hydraulic

- Determination of the efficiency
- Recording of characteristic curves
- Influence of the nozzle cross-section of the Pelton

  turbine on the characteristics  
- Influence of the guide vane position of the Francis

  turbine on the characteristics  


[1] Comparison of a Pelton turbine as impulse turbine and a Francis turbine as reaction turbine
[2] Accessories for the HM 365.32 Turbine Supply Unit
[3] Operation by use of the HM 365 Universal Brake and Drive Unit
[4] Constant torques and speeds can be adjusted with HM 365
[5] Transparent front panel in the turbines for observing the operating area
[6] Adjustable nozzle needle for setting different nozzle cross-sections (Pelton turbine)
[7] Adjustable guide vanes for setting different angles of incidence (Francis turbine)
[8] Pressure sensor at the Francis turbine for measuring the pressure at the turbine outlet
[9] Digital display for flow rate, pressures and temperature in HM 365.32
[10] Braking torque and speed measured in HM 365 


Technical Data

Translation ratio between brake and turbine: 1,44:1 
Pelton turbine 
- output: 1,5kW at 2750 min-1 at 6,5bar
- wheel diameter: 165mm
- variable nozzle setting
Francis turbine 
- output: 1kW at 3500min-1 and 4,2bar
- wheel diameter: 80mm
- variable guide vane setting


Measuring range
- pressure (outlet on Francis turbine): 0...1,6bar


Dimensions and Weight
LxWxH: 500x500x500 mm
Weight: together approx. 50kg
Required for Operation
HM 365.32 (closed water circuit)
Scope of Delivery
1 Pelton turbine 
1 Francis turbine
Order Details
070.36531  HM 365.31  Pelton and Francis Turbine