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Title: Effects of potting on training and quench propagation in a large stored energy superconducting dipole coil

Conference ·
OSTI ID:6846537

A superconducting racetrack dipole coil was constructed to compare directly training and quench behavior in potted and non-potted coils. The stored energy of this coil was 175 KJoules at the conductor's short sample limit of 238 Amp with a peak field on the coil of 7.6 Tesla. The outward magnetic forces were restrained by rows of tie rods between side plates. Comparisons of training behavior were made for both steel and aluminum tie rods. Helium flow was provided by channels in the fiberglass cable tape allowing 1/4 of the conductor direct access to the helium supply. After training the coil to 90% of short sample limit, the tie rods were relaxed and the entire coil was vacuum impregnated with a standard clear magnet epoxy. After potting, the previous tie rod preloads were re-established. This resulted in a much shallower training curve, and required retraining after thermal cycling. The unpotted coil showed no evidence of internal quench propagation below 80% short sample, whereas the potted coil exhibited good quench propagation and energy dissipation at all currents, simplifying protection strategies. Fully impregnated coils of this design are not practical for thermally cycled magnets designed to operate above 80% of short sample limit.

Research Organization:
Fermi National Accelerator Lab., Batavia, IL (USA)
DOE Contract Number:
AC02-76CH03000
OSTI ID:
6846537
Report Number(s):
CONF-800980-17; TRN: 80-019065
Resource Relation:
Conference: Applied superconductivity conference, Santa Fe, NM, USA, 29 Sep 1980
Country of Publication:
United States
Language:
English