Development of Bi-2223 Model Magnet for Magnetic Refrigeration System

We have started the development of a magnetic refrigeration system for hydrogen liquefaction. This system comprises a superconducting magnet, wherein an active magnetic regenerative (AMR) bed moves through. To investigate its applicability to the magnetic refrigeration system, a Bi-2223 superconducting magnet with compensation coils at both ends was designed and fabricated. The magnet was designed to generate 4.76 T at a rated current of 300 A. Compensation coils at both ends reduce the magnetic field outside the bore to zero. The magnet was fabricated as a stack of epoxy-impregnated double-pancake coils. The cooldown period of the magnet was approximately 82 hours. However, the quench detector ceased the power supply at 229 A (3.63 T), due to voltage oscillations in the coils, likely arising from compression due to the magnetic repulsive force.