The air gap between the test object and the magnetizing yoke
was adjusted to be 0.1 mm by considering the contact condition
between the magnetizing yoke and the test object. The air gap
between the type A standard test shim and the test object was
also similarly set to 0.1 mm in order to obtain the analytical
results indicated in Tables 1 and 2. The air gap between the type A
standard test shim and the test object was changed from 0 to
0.2 mm to obtain the analytical results shown in Figs. 3–7. The
excitation current frequency of the magnetizing yoke was 50 Hz,
which is the commercial current frequency and the excitation
current values of the magnetizing yoke were the same as in the
experiment.