NCM and BEV will compare the following voltages in order to determine the agreement between both laboratories:
- DC voltage: 1,018 V and 10 V
- AC voltage: 1 V and 10 V at frequencies 44 Hz, 1 kHz, 100 kHz
Additionally DC voltage at 100 mV and AC voltage at 10 mV and 100 mV – 44 Hz and 1 kHz should be measured at both institutes but not considered as part of the comparison.
A multifunctional transfer standard Wavetek 4950 from NCM will be used as travelling standard.
Final Report 2006-04-28
NCM and BEV compared the following voltages:
DC voltage: 1.018 V and 10 V
AC voltage: 1 V and 10 V at frequencies 44 Hz, 1 kHz, 100 kHz
Additionally DC voltage at 100 mV and AC voltage at 10 mV and 100 mV – 44 Hz and 1 kHz were measured at both institutes but not considered as part of the comparison.
A multifunctional transfer standard Wavetek 4950 from NCM was used as travelling standard. The measurements were carried out in February/March 2003. The Draft A and Draft B reports were available in 2004/2005. The final report was finished in April 2006.
The main objectives of the comparison were:
- to demonstrate equivalence of metrological practice
- to contribute to acceptance of NCM in EUROMET
- to confirm the CMC of NCM in the field of DC and AC voltages
- to check the correctness of the calibration results
- to check the correct traceability of the standards
As the first results of NCM failed to coincide with the reference value within the stated uncertainty of NCM, the pilot laboratory asked NCM to recalculate their values. After NCM recalculated their uncertainty budget the results showed an agreement within the stated uncertainties. Due to the fact that this procedure is not in line with the key comparison guidelines it was decided after discussion with the TC-EM chairman and the BIPM, to withdraw both entries of this comparison (EUROMET.EM.BIPM-K11.4 “Key Comparison of DC voltages” and EUROMET.EM-S17 “Supplementary Comparison of AC voltages”) from the BIPM key comparison database.