COMPARISON OF DIFFERENT LOAD CHANGERS FOR EMFC-BALANCES |
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| F. Hilbrunner, H. Weis, T. Fröhlich, G. Jäger |
- Abstract:
- In order to further improve the metrological properties of weighing systems based on the principle of electromagnetic force compensation (EMFC) as well as quality assurance, it is necessary to determine the parameters relevant for the dynamic operation, such as measurement time and controller behavior. This determination is carried out by loading the balance system and observing the indication. Typically this is done by a load changer using different metrological weights. This method is inevitable if metrological traceability is required. However, the conventional procedure of load changing also entails several disadvantages. The number of possible load changes per unit time is limited and the force characteristic during loading is usually unknown and relatively difficult to reproduce or manipulate. Furthermore the fast and sudden exchange of the weights causes mechanical vibrations and a movement of the surrounding air, both of which act as additional disturbances.
In this paper we propose an alternative loading method, with which these shortcomings can be improved and compare it to a conventional system. This method is based on loading the weighing system in a defined manner using a Lorentz-force, allowing the tester to generate a known, virtually arbitrary force characteristic during loading.
It is shown that the Lorentz-force generated load represents a practical alternative to classical weights, offering advantages in reproducibility, dynamics and ability to be automated. Since the proposed method applies a known Lorentz-force to the weighing system it becomes possible to exactly determine the relationship between the force acting on the weighing pan and the resulting behavior of the weighing system. - Keywords:
- check weigher, measurement time, load changer
- Download:
- IMEKO-TC3-2010-016.pdf
- DOI:
- -
- Event details
- IMEKO TC:
- TC3
- Event name:
- TC3 Conference 2010
- Title:
21st Conference on Measurement of Force, Mass and Torque (together with TC5 HARDMEKO 2010 and 2nd TC22 Meeting on Vibration Measurement)
- Place:
- Pattaya, THAILAND
- Time:
- 21 November 2010 - 25 November 2010