Spike voltages seen during "quick charge" ramp limitation tests on Nb/sub 3/Sn cable-in-conduit conductors

Spike voltages observed during ramp rate limitation tests on sub-sized Nb/sub 3/Sn cable-in-conduit superconductors are analyzed using current loop model. The effects of loop currents on the ramp limitations of multi strand superconducting cables are discussed. Current loops existing in multi strand cables generate excess local currents that quench strands and produce voltage spikes. Experimental results previously reported as abnormal ramp rate limitations are explained by loop current phenomena.