The authors developed and tested a superconducting mechanical persistent current switch for SMES applications. For the purpose of improving electric current carrying capacity of one contact up to the kA level, multiple rods of NbTi with a copper matrix were selected. Pre-experiments surveyed current carrying capacity and electrical resistance of valuable contact samples, that were different in diameter of NbTi, shape of contacts and surface treatment. Vacuum valves were manufactured on trial with most suitable contacts for this purpose, and tested in liquid helium. A quench current up to 1900-2000 A DC at single valves, and 4570 A DC at four parallel valves, resulted. The electrical contact resistance before quench was lower than the measuring resolution (>1/spl times/10/sup -10/ ohm). Vacuum valve open/close speed was improved using coned disk springs and electromagnetic repulsion coils for the driving mechanism. With repeating open/close cycles, quench currents were observed to decrease. Therefore the closing mechanism should be improved.
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机译：作者开发并测试了用于SMES应用的超导机械恒流开关。为了将一个触点的载流能力提高到kA级别，选择了多根NbTi与铜基体。实验前调查了有价值的接触样品的载流量和电阻，这些样品的NbTi直径，接触形状和表面处理均不同。真空阀是通过试验制造的，为此目的使用了最合适的触点，并在液氦中进行了测试。在单个阀上的淬火电流高达1900-2000 A DC，在四个并联阀上的淬火电流为4570 A DC。淬火前的电接触电阻低于测量分辨率（> 1 / spl次/ 10sup -10 / ohm）。通过使用锥形碟形弹簧和电磁排斥线圈作为驱动机构，提高了真空阀的打开/关闭速度。随着重复的开/关循环，观察到淬火电流降低。因此，关闭机构应加以改进。
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