The angular vibration calibration system is not well established even in most of NMI’s. Moreover, it is not certain that suppliers of angular vibration pickups have well maintained the traceability of their calibration systems, unlike the linear vibration calibration systems well established in the industrial sector. This paper points out several technical issues encountered in setting up the angular vibration calibration system in KRISS. The first was to develop a new angular vibration exciter that is not commercialized yet. The angular vibration calibration system can not do without the...
In this paper, a new primary calibration system for the frequency range from 5 kHz to 10 kHz at the National Metrology Institute of Japan (NMIJ) is reported. In the high frequency range, the displacement amplitude becomes small and the effects of parasitic motion, such as drift motion and external noise, become greater with increasing frequency. Therefore, the realization of the primary calibration system becomes difficult. The new primary calibration system for the high frequency range is implemented with a newly designed laser interferometer and a new signal processing algorithm, which is...
Korea Research Institute of Standards and Science(KRISS) has developed a 100 N·m and a 2 kN·m deadweight torque standard machines. The 100 N·m torque machine can generate torque from 0.1 N·m to 110 N·m. The length of its torque arm is 0.25 m for both sides. It uses continuous deadweight stack. At each side, it has three different deadweight stacks. By rotating the base plate on which the deadweight stacks are located, the machine can adjust a suitable deadweight stack of appropriate torque range. Its relative uncertainty is 5 × 10 -4 from 0.1 N·m to 1 N·m and 5 × 10 -5 from 1 N·m to 110 N·m....
In December 2005, the new version of the DIN 51309 was issued by DIN, the German Institute for Standardization. This standard takes into account some fundamental ideas about the target application of a torque transducer, for example high-level inter-comparison measurements or measurements in industrial environments. Two cases are considered and two different calibration results are calculated on the basis of a standard calibration procedure. For some intercomparisons, the hysteresis of the transducer does not have any influence on the result and is therefore excluded. This paper shows, on...
This paper describes the advantage of carrier frequency amplifiers in rotating torque flanges. It gives an overview of the systematic effects and random errors which disturb the torque measurement and shows how the measurement errors can be suppressed by means of carrier frequency technology. The resulting high reproducibility and linearity of the new torque flange with digital signal processing and transmission is shown in torque and temperature plots.
Expansion of the calibration range and improvement of the uncertainty of realized torque in the 1 kN·m deadweight torque standard machine were investigated. The lower limit of the calibration range was lowered from 5 N·m to 0.5 N·m by developing new small linkage weight series. In addition, the sensitivity limit at the fulcrum was reevaluated. The moment-arm length was also re-measured after changing the thin metal bands at the ends of the moment-arm. As a result of these evaluations, relative expanded uncertainties (k = 2) of 7.3 × 10 -5 and 2.9 × 10 -5 could be obtained in the range from...
Investigations with regard to the mathematical description of reference torque transducers used in comparison calibration facilities are described. A method is presented which uses only the direct loading calibration data of a torque transducer in the full range in order to calculate its behaviour in any reasonable partial range. Examinations of typical reference torque transducers demonstrate how to find transducers which are qualified for this calculation method and provide estimations of the possible effects on the measurement uncertainty caused by the calculation of the partial-range...
This paper describes the new LNE 50 N·m deadweight torque standard machine. Informations on the design, development, and commissioning of this standard are given. Its design is described focusing on mechanical and metrological characteristics in particular of the structure, the deadweight, the air bearing and the lever arm.
In 2001, in order to improve the confidence level and the accuracy of the torque calibration systems in Brazil, the Force, Torque and Hardness Laboratory (Lafor/Inmetro) acquired a Torque Primary Standard Machine from 20 N·m up to 3000 N·m of nominal range, in clockwise and in anti-clockwise, where it was qualified by PTB/Germany in 2004. Since them, some steps have been done to disseminate the improved torque results to the users. The present work has the objective to demonstrate how Inmetro/Lafor is preparing to manage the torque metrology in Brazil due to the best measurement capabilities...
Primary vibration calibration by laser interferometry using quadrature outputs has been used for the last 10-15 years. The ISO 16063-11 was published in 1999 and this has increased the interest further. With new compact laser interferometers the difficulties of optical alignment and adjustment has been practically eliminated and dedicated software has made the process automatic, permitting to gather much more data. Furthermore the advancement in electronic measurement capabilities, especially in high precision A/D converters, has made the electrical parts of the error budget very small....