Development of a Multicoil Medium-Sized Superconducting Magnet With Zero-Vapor LHe

A medium-sized superconducting magnet wound using NbTi wires was designed, fabricated, and tested. It has been developed for a superconducting magnetic energy storage system. The solenoid magnet has a clear bore of 250 mm, an outer diameter of 380 mm, and a height of 589 mm. The magnet consists of one main coil and two compensating coils and is dry wound using rectangular superconducting wires with dimensions of 1.28 mm × 0.83 mm. Grooves and reinforced bulks are designed on the supporting structure to improve the cooling ability and the mechanical strength. A cryogenic system has been designed to keep the liquid helium in the zero evaporation state. The magnet has been tested in a compact cryostat, and it generates a central magnetic field of 4 T at the designed operating current of 126 A. The results of the experiment show that the performance of the magnet reaches the requirements. The details of the design, fabrication, and test of the superconducting magnet are presented in this paper.