Alternative concept for winding of coils from high-temperature superconducting tapes has been investigated. Conductor-On-Round-Tube (CORT) conductors with tapes helically wound on a metallic tube have been manufactured and used to wind single layer coils with the bore diameters between 116 and 325 mm wound and tested in the dc regime. Results were analyzed with the help of numerical calculations considering the critical current density dependence on magnetic field derived from the short sample measurement. We have also modified the standard approach by including the fluctuations of critical current along the tape length into the calculations. Results have shown that the uniformity of critical current is essential for achieving predictable cable and coil performance.
