Investigation of the Dynamic Behaviour of PTB Deadweight Force Standard Machines

This paper describes the behaviour of deadweight force standard machines of 100 kN and 1 MN at the Physikalisch-Technische Bundesanstalt(PTB). A build-up system was used to measure the dynamic behaviour of the deadweight force standard machines. The oscillating signals from the force-transducers in a build-up system are much larger than those from a single force-transducer. This is because the force-transducers in a build-up system are located several tens of millimeters from the centre of the force-standard machine. Hence, small movements of the deadweight result in changes in the reaction forces of the build-up system, which are amplified by the lever mechanism. The frequency and the trajectory of the pendulum’s movements are investigated. The trajectories of the pendulum’s movements are estimated by using force signals from the build-up system. In addition to that, the major and minor radii, direction of the elliptic motion and the rotational direction as functions of time are estimated to interpret the pendulum’s movements more meaningfully. The two machines show somewhat different dynamic behaviour. 1