Products - Dynamometers - Eddy Current Dynamometers AG Type

Froude Eddy Current Dynamometers: Exceptional Accuracy and Low Inertia 

eddy current dynamometer

The Air Gap (AG) range of Eddy Current Dynamometers has been designed to be compact, robust and to allow easy maintenance. The narrow yet durable design, small footprint, and the exclusive material and construction technique ensures many years of service. These units are bi-directional, fitted with 40,000-hour bearings and extremely accurate (0.25% Full-Scale Torque). 


Each eddy current dynamometer is fitted with oil injected half couplings at either end of a non-magnetic stainless steel shaft which is supported in grease lubricated, deep groove ball bearings. The non-magnetic shaft means negligible magnetic field dispersion. The dynamometer casing houses twin magnetizing coils that produce a retarding controllable magnetic field that resists the applied torque. Heat generated in this process is dissipated by cooling water.


Rotation of the casing is resisted by a precision strain gauge load cell that gives an accurate measurement of total input torque.


Model Max Speed (RPM) Torque Nm (lb.ft) Power 
kW (BHP)
Curve Ref
AG30 12,000 95 (70) 30 (40) 003606
AG30-HS 14,000 95 (70) 30 (40) 003796
AG80 9,000 160 (118) 80 (105) 003607
AG80-HS 14,000 160 (118) 80 (105) 003797
AG200 8,000 800 (590) 200 (270) M011807
AG350 9,000 1,500 (1,120) 350 (470) M014810
AG500 7,500 3,000 (2,210) 500 (670) M011581
AG750 4,000 4,500 (3,320) 750 (1,010) M005985
AG750HS 5,500 4,500 (3,320) 750 (1,010) M008380


The Air Gap range of Eddy Current Dynamometers has been designed to be compact, robust and to allow easy maintenance.

Main Features:

  • Torque measurement accuracy ±0.25% of full rated torque of dynamometer
  • Speed measurement accuracy ±1 RPM using Froude controller
  • Low inertia 
  • Non-magnetic stainless-steel shaft
  • High balance (G2.5)
  • Low current draw (less than 10 amp for the complete range)
  • Bi-directional 
  • High reliability and durability  
  • Easy maintenance
  • Small footprint


  • Development and production testing of gasoline and diesel engines
  • Engine component test rigs
  • Electric motor testing
  • Educational rigs
  • Gearbox test rigs


The standard AG dynamometer range extends from 30 kW to 750 kW at speeds up to 12,000 rpm and can absorb power in either direction of rotation.

Torque measurement accuracy is ±0.25% of full rated torque of the dynamometer. The speed is measured by a pulse pickup operating with a 60 tooth wheel and gives accuracy of ±1 rpm.

Froude dynamometers are painted traffic blue RAL 5017.

Visit our Global Sales Page to inquire about Froude Equipment, or fill out the contact form below.

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  • High speed versions up to 14,000 rpm
  • Calibration equipment
  • Shaft bearing thermocouples
  • Cooling water inlet filter
  • Terminal box electrical connector
  • Drive end water connections
  • Paint color

Customer Service

  • Facilities planning and installation services
  • Comprehensive in-house and/or on-site training courses
  • Tailored preventative maintenance contracts
  • Technical Support


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