Effects of Moving Magnetic Materials in and out of Superconducting Magnet for Active Magnetic Regenerative Refrigeration System

A reciprocating type active magnetic regenerative refrigeration (AMR) utilizes the magnetocaloric effect of magnetic materials which occurs during magnetization and demagnetization processes by moving magnetic materials in and out of a magnet. Estimating the induced voltage and electromagnetic force in the superconducting magnet during the reciprocation is crucial to optimize the design of the AMR system. This paper represents the behavior of the superconducting magnet during the AMR operation that the magnetic material HoAl2 weighing 250 g enters and exits the 120 mm bore NbTi superconducting coil. The calculation and measurement results of the induced voltage and electromagnetic force in the magnetic field of 0-5 T at 25 K were reported.