LORENTZ FORCE SIMULATION TESTS ON A FULL-SCALE PROTOTYPE MODEL COIL OF THE 45-T HYBRID MAGNET

摘要

The 45-T Hybrid Magnet at NHMFL employs cable-in-conduit conductor design for the superconducting coils. The coils are electrically insulated with glass-fiber reinforced epoxy. The steel conduit acts as the main structural component to resist large Lorentz forces but the insulation is constrained to endure similar strain. The structural and electrical integrity of the insulation must be assured over the lifetime of the magnet during which it will experience full strain range for approximately 1000 charge/discharge cycles. A full scale-model coil (about 1 m diameter), that was constructed to address fabrication issues, also provides a prototype sample for the mechanical and electrical tests described here. By side-loading the coil, in proving ring fashion, a strain equivalent to the operating strain is imposed at the quadrant points of the coil. A finite element analysis simulating the test is performed to support the test results. The coil is fatigue tested for 100 cycles at 295 K and 1000 cycles at 77 K. The electrical resistance of the insulation is measured before and after mechanical testing. The coil insulation performance and interpretation of test data are presented.