Metrological qualification of the new 5 N⋅m and 50 N⋅m torque standard machines of LNE

After the development of two new torque standard machines, LNE realized their metrological qualification. This paper describes the determination of the uncertainties of these torque standard machine, including the uncertainty due to the mobility and the sensitivity of the moment arm. It describes also the comparisons carried out with the national metrology institutes of Spain (CEM) and Germany (PTB). The results show that the estimated uncertainties are satisfactory because divided by a factor of at least five compared to the old standard machines.