  Direct current (DC) characterization of high temperature superconducting
(HTS) coils is important for HTS applications, such as electric machines,
superconducting magnetic energy storage (SMES) and transformers. In this paper,
DC characterization of a circular, epoxy-impregnated HTS coil made from YBCO
coated conductor for use as a prototype axial flux HTS electric machine is
presented. Multiple voltage taps were utilized within the coil during
measurement to help provide further detailed information on its DC behavior as
a function of length. Based on the experimental results, there exist regions of
non-uniformity along the length of superconductor in the coil, resulting in
non-ideal superconducting properties of the coil. By studying the
current-voltage (I-V) curves across different regions, it is found that a
decreasing n-value and critical current exists in the non-uniform parts of the
HTS coil.
