Hydraulic dynamometer, water brake

Hydraulic dynamometer work compartment consists of blades and stainless steel rotors and stators. Water flows through the blades in a circular vortex mode, producing torque response through the dynamometer housing, and the torque response is measured by a precision load cell. The load cell signal is passed to the load cell amplifier.

The water level and load of the hydraulic dynamometer are controlled by the outlet valve and operated by a closed loop electro-hydraulic servo system. The dynamometer control command passes to the water valve. The power absorbed by the dynamometer is carried away by water in the form of heat.

POWERLINK SG series water brake (hydraulic dynamometer) is under the international advanced level and has been widely sold abroad. Water Brake has a total of more than 10 specifications with electric butterfly valve control. By changing the butterfly valve opening, the absorbed power amount is changed. The braking power ranges from 120kW to 3600kW.

Hydraulic dynamometer is mainly used to detect the effective power of various diesel engines, gasoline engines, electric motors, automobile transmission parts, gas turbines, hydraulic turbines and other power machines, which is an indispensable test equipment for the test of power machine characteristics and efficiency of transmission machinery.


Hydraulic dynamometer, water brake


Major features of water brake


  • Small size, easy to install
  • Simple structure, easy operation and maintenance
  • Large braking torque
  • High measurement accuracy
  • Stable and reliable
  • Using magnetic speed sensor to achieve high-precision instantaneous speed measurement
  • Electronically controlled butterfly valve for fast load control


Hydraulic dynamometer, water brake

Hydraulic dynamometer, water brake major parameters


ModelAbsorption power (kW)Braking torque (Nm)Max. speed (rpm)

* The maximum speed can be adjusted based on customer needs



Water brake major technical specifications


  • Cooling medium: Clean and fresh water, free of impurities and debris
  • Cooling water pressure: 0.05 ~ 0.15Mpa
  • Water pressure fluctuation range: ±5KPa
  • Hydraulic dynamometer water outlet temperature: Less than 70℃
  • Direction of operation: Single direction right-handed (Bi-directional as option), continuous work
  • Torque measurement accuracy: ±4% FS (SG120 to SG380), ±0.2% FS (SG400 to SG3600)
  • Speed measurement accuracy: ±1rpm
  • Torque measurement sensor: Tension-compression force transducer
  • Speed measurement sensor: 60 pulse magnetic-type speed sensor


Hydraulic dynamometer, water brake


Work principle of water brake


The power machine drives the rotor assembly on the main shaft through the coupling for synchronous rotation and stirs water in the working chamber. Due to the centrifugal force generated by the rotation of the rotor and the function of rotor pits, water produces a strong water vortex between the side housing and the rotor pits, which gives the housing a rotating torque which transmits the torque of the power machine from the rotor to the casing.

The power arm on the housing will rotate an angle to transmit the braking torque to the pull pressure sensor connecting with the brake arm and display the braking torque through the electronic digital display device.

The water brake controls the opening of the butterfly valve through the electric drain valve, or the drainage actuator is controlled by the automatic regulating device. The butterfly valve opening is controlled by the drainage actuator to change the amount of the absorbed power by changing the water pressure in the hydraulic dynamometer working chamber.

At the same time hydraulic dynamometer speed can be measured by the speed sensor and displays through electronic display.

As a pressure-controlled hydraulic dynamometer and changing the butterfly valve opening for working chamber pressure adjustment, the whole process must be an automatic closed-loop control system, so the pressure-controlled dynamometer must be equipped with automatic control function cabinet in order to run the job.


Hydraulic dynamometer, water brake


Water brake structure major components


  • Body parts
  • Force measuring mechanism components
  • Water inlet and drainage components
  • Calibration components
  • Electric drain valve assembly
  • Automatic adjustment device components
  • Lubrication components


Parameter selection and curve download



Application description download