Experimental Device to Electromechanically Characterize 3-Strand $\hbox {Nb}_{3}\hbox {Sn}$ Samples Under Transverse Load

Triplet cables are the basic cable element of CICC cables, and understanding their electromechanical behaviors under transverse loads is of critical importance to evaluate the electromagnetic behaviors of large cables. This paper describes a new compact experimental device to characterize electromechanically single strand and triplet cable samples as well as HTS tapes under transverse loads. The device has been built and tested with significant reduction of the cost of the experiment compared to a previously used hairpin sample device. Critical current measurements as a function of transverse mechanical load at 12 T were successfully performed on triplets using ITER Nb₃Sn wire. The transversely loaded section of the samples is 110 mm in length, longer than the typical twist pitch lengths of first-stage triplets of CICC. The load is applied by using a gear system driven by a 1/2 HP motor. A wedge, vertically displaced by the motor, moves other pressing components transversely. Those parts ultimately apply transverse compression on the cable. A load cell and an extensometer are used to measure the absolute vertical load and displacement, respectively. Limitations and challenges of this compact transverse load device design are discussed together with some experimental results.