Linear Media Handling System for Superconductor Cable Fabrication

Superconductors offer the promise of tremendous energy savings and innovative devices due to increased energy and power density compared to existing limitations of conventional conductors. To date the expense of manufacturing and operating superconductors have limited their use in little more than first generation superconductor wound cables and magnets in nuclear magnetic resonance devices and science experiments such as particle accelerators. First generation superconductors are ductile and accommodating to fabrication but commercially constrained because operational environments require extreme cryogenic temperatures. Modern superconductor materials such as YBCO have been discovered to have operational temperatures in the commercially feasible range of liquid nitrogen, but such materials have proved too difficult for fully automated handling systems. Manual winding techniques remain standard because of the fragile nature of superconductor materials, especially the need for guided precision to address high thermal, magnetic, and mechanical stresses in superconductor component operating environments that are exacerbated by any flaws in the wound material. With maturity of superconductor material production and cryogenic systems, inconsistency and cost of handcrafted production of superconductor linear media components has become the primary factor preventing capabilities and commercialization across many industries. This Small Business Innovation Research project proposes the development of a machine that improves capability, reliability and production rate of cables incorporating modern superconductors. The objectives of the proposed research include automating production with fidelity superior to manual processes and demonstrating that yield strength has not been exceeded during fabrication of cables made from fragile superconducting tape such as YBCO and even reacted wire materials including Nb3Sn and MgB2. A precursor to the proposed cable winding machine is being developed under a patented government funding award to handle the shaping of fragile superconductor materials into wound magnets. As with this developing innovative magnet winder, the proposed cable winding machine combines non-linear closed-loop controls, specially designed direct tension sensors, and precision motion control equipment to guide the output of material and contact location of the wind. Based on achievements for wound magnets, it is anticipated that this method can be successfully adopted for the more complex problem of fabricating wound cables. Phase I research will develop a prototype winding machine embodying precision linear motion of the cable substrate orchestrated with patent pending tension sensing data from multiple linear media emanating from spools arranged in precision rotary motion about the wind axis. Phase I prototype testing will involve production of non-superconductive and superconductive media. The anticipated result is a production capability that offers economically attractive output rates while simultaneously delivering technical reliability for dependable devices exploiting the benefits of modern superconducting cables and magnets. This cable fabrication tool will then catalyze an industrial revolution due to the energy density, power density, and high efficiency capabilities of superconductor devices that it makes commercially attainable. Through automation resulting in low cost and consistent specifications, SC cables will become common elements used in the advancement of electric power generation and transmission, electric motors, transformers, and other applications such as science magnets. This innovation will impact industries from medical imaging to transportation to defense to fusion research.