In this paper we report on the measurements of the critical current of a ta
pe-formed high-temperature superconductor in a magnetic field corresponding
to the field at different positions in a (transformer, reactor or magnet)
winding. An, applied magnetic field reduced the perpendicular component of
the self-field of the sample. The measurements were performed in liquid nit
rogen on a silver-sheathed Bi-2223 conductor. The results show a significan
t increase of the critical current with reduction of the perpendicular comp
onent of the self-field.