Physikalisch-Technische Bundesanstalt

The Working group 1.22 is responsible for the realization of the physical quantity of torque. The torque is defined as the product of an acting force and its perpendicular distance to the centre of rotation considered. Therefore the unit of the torque is derived from the unit of the force (the Newton N) and that of the length (the Meter m). The Newton itself is traced back to the basic units of the International System of Units (SI) Kilogram, Meter and Second.
Two cases of the torque measurement can be treated: a 'pure' torque (generated by a force couple, application in torque transducers) and a torque with superimposed cross forces and bending moments (generated by a single force, application in torque wrenches). In addition, a subdivision into static (quasi constant torques with or without rotation) and dynamic (varying with time) torques must be made.
The field of activity ranges from fundamental metrological research, the development of standard machines to the calibration of transducers and consultation. Another application is the measurement of the rotational power in medical ergometers, which are traced back to the erometers standard in the torque working group.