Reaction Heat Treatment and Epoxy Impregnation of a Large \hbox\hbox CICC Coil for a Series-Connected Hybrid Magnet

• Published in: IEEE transactions on applied superconductivity 2014-06, Vol.24 (3), p.1-5
• Main Authors: Dixon, Iain R., Adkins, Todd, Ehmler, Hartmut, Marshall, William S., Bird, Mark D.
• Format: Article
• Language: English
• Subjects: Cable-in-conduit conductors (CICC); Coils; hbox{Nb}_{3}\hbox{Sn}; Heat treatment; hybrid magnets; Insulation; Joints; Superconducting magnets; Temperature measurement; Windings
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2013.2287756

Recent activities that were conducted on the Helmholtz Zentrum Berlin Series-Connected Hybrid outsert coil included the reaction heat treatment and vacuum-pressure impregnation. A thermocouple was wound into the windings for diagnostic purposes during processing of the coil. To maintain a reasonable temperature differential across the coil, the ramp rate was limited to approximately 2.7°C/hr. Epoxy impregnation was conducted with an epoxy developed in-house. The epoxy is transferred in vacuum but cured with one atmosphere gage pressure applied. Subsequently, the winding hardware was removed including the stainless steel mandrel through a machining operation. After assembly of voltage breaks and voltage taps, Paschen tests to 4 kV were conducted successfully that qualified the ground insulation. In addition, surge tests to qualified the internal insulation with 3 kV applied across the leads were conducted. Impedance measurements were conducted to confirm the internal insulation integrity.