The Froude F Range Hydraulic dynamometers have been designed to be compact, robust and to allow easy maintenance.

These dynamometers are fitted with two half couplings which, with the rotor, are oil injected onto the shaft. The standard machines run in grease lubricated rolling element bearings.

The hydraulic dynamometer working compartment consists of special semi-circular shaped vanes cast into stainless steel rotor and stators. Water flowing in a toroidal vortex pattern around these vanes creates a torque reaction through the dynamometer casing which is resisted and measured by a precision load cell. The dynamometer load is controlled by a 'butterfly' water outlet valve, operated by a closed loop electro-hydraulic servo system. The power absorbed by the dynamometer is carried away by the water in the form of heat.