New proposal to reduce training for potted superconducting coil in relation to composite stress/strain effects

A new facility was completed which is capable to study stress/strain effects in ''training in circular'' coil with I.D. 10 mm and 'race track' shaped small coil with 120 mm length and 14 mm width. Several potting materials (wax, epoxy) were examined. New findings show that the training can be greatly reduced by applying external force and unloading along the long axis during energizing the coil. This improvement is to be explained by the composite interaction between wire and potting material which involves thermal disturbances and/or wire movement. If the present method is applicable to some medium sized and/or large bore magnet, one of the difficulties in magnet technology is to be solved by mechanical treatment. 13 refs