Transport behavior and stability of inductors for international comparisons

A key quantity in the field of electromagnetic measurements is inductance, 10 mH measured at 1 kHz. A comparison CCEM-K3 [1] was finished in 2001 with a good result: a relative expanded uncertainty of 4·10-6 could be achieved. However, this old comparison did not cover all regions, a repetition is necessary. To achieve again the necessary low uncertainty quite high requirements on the stability of the standard have to be fulfilled. A good knowledge of the quality of inductance standards is therefore inevitable. This paper describes the parameters which are important to carry out the comparison.