Investigation of magnetic interactions between mass standards and weighing instruments
Measurements and mathematical models on the magnetic field of a weighing instrument and of its interaction with magnetic and magnetically susceptable weights have been made and presented by some of the participants.
PTB has measured the magnetic field distributions of several balances, has adjusted the parameters of two point dipoles to the measurement results and has calculated the interaction with cylindrical weights of given simple magnetic properties. It was shown for a particular balance, that characteristic parameters for different weight sizes can be developed, which enable a simple arithmetic calculation for the interaction force with a weight of given magnetic properties and at given ambient magnetic field.
BIPM has confirmed these parameters by a different approach using the formulas of the BIPM susceptometer. BIPM presented also a detailed uncertainty calculation for the susceptometer by taking account of the corresponding correlations between the parameters concerned.
MIKES presented measurements of the magnetic field distributions of several weighing instruments.
Publications
- M. Gläser: Magnetic interactions between weights and weighing instruments, Meas. Sci. Technol. 12 (2001), 709-715
- R. S. Davis, M. Gläser, R. Heierli, M. Malina, L. R. Pendrill and Ph. Richard: Intercomparison of Magnetic Properties of Mass Standards, 2001 Proceedings 10th International Metrology Conference, St. Louis (FR), October 2001
- J.W. Chung, K.S. Ryu, R.S. Davis: Uncertainty analysis of the BIPM susceptometer, Metrologia, 38 (2001) 535-541