We usually measure AC losses of superconducting wires and cables exposed to
a transverse AC magnetic field by a pickup-coil method, In this case, a ma
in pickup coil is coaxially located around the sample wire wound as a solen
oidal coil. An additional pickup coil (a cancelling coil) is also placed in
side or outside the sample coil, This method is advantageous to obtain de t
ailed electromagnetic properties of the sample, In the present study, we di
scussed the effect of the geometrical configurations of the sample and pick
up coils on AC losses measured by the pickup-coil method for three types of
arrangements of the cancelling coils. We analytically calculated interlink
age magnetic flux into the pickup coils due to magnetic moments induced in
the sample wire, and formulated the geometrical errors in the pickup-coil m
ethod. We also prepared some sets of sample and pickup coils, and compared
observed AC losses with the theoretical predictions.