Engine AC Dynamometers

The Froude AC dynamometer has been specifically designed for testing of gasoline and diesel engines in R&D and Quality Audit applications.  The construction utilises a special low inertia AC motor providing exceptional performance in control and torque measurement,  designed for steady state, transient and dynamic testing applications.  The dynamometers are supplied in either foot mounted in-line torque hub format, which also includes a jackshaft to provide a high overhung load capability to accommodate heavy duty drive shafts, or in a trunnion mounted format using a strain gauge load cell, measuring the torque reacted off the motor casing.  In both formats the motor is cooled by forced ventilation using an integral cooling fan. 
 
The AC dynamometer is supplied with a 4-quadrant flux vector AC inverter. This state-of-the-art technology incorporates high speed IGBT (Insulated Gate Bipolar Transistor) and sophisticated control algorithms to provide excellent transient response and steady state control. The drive incorporates a special input stage that operates at near unity power factor, minimises supply current harmonics and in re-generation mode frequency matches to the mains supply. The AC dynamometer and inverter drive unit are designed for use with Froude Hofmann’s range of Texcel control and data acquisition systems.

Main Features:

• The Froude Hofmann standard range of AC dynamometer consists of eight machines from 140kW to 690kW. Other sizes are available on request.
• Standard torque measurement accuracy is better than ± 0.2% of the full rated torque of the dynamometer.
• Speed is measured using an encoder and a 60-tooth wheel, providing an accuracy of ± 1 rpm.
• Transient response of up to 9000 RPM/sec.
• Transient and emission test capability.
• Fast and accurate dynamic response.
• Low inertia.
• High coupling load capability.
  

Automotive Engine Test