Title :
AC loss measurements with a cryocooled sample
Author :
Schwenterly, S.W. ; Demko, J.A. ; Lue, J.W. ; Walker, M.S. ; Reis, C.T. ; Hazelton, D.W. ; Shi, Xin ; Gardner, M.T.
Author_Institution :
Oak Ridge Nat. Lab., TN, USA
fDate :
6/1/2001 12:00:00 AM
Abstract :
A new cryostat cooled by a closed-cycle Cryomech GB-37 cryocooler for superconductor measurements at temperatures down to 20 K is described. The sample is conductively coupled to the cold stage so as to minimize vibration and thermal stresses. AC losses have been measured calorimetrically in several high-temperature superconductor coils that have been wound to simulate subscale transformer winding pairs. Stable temperatures down to 20 K were reached on these coils, allowing measurements at practical levels of AC current and Ic. By using short AC current pulses, losses on individual turns could be resolved. Results are reported mainly to showcase the apparatus, measurement procedure, and analytical approach
Keywords :
cryostats; high-temperature superconductors; loss measurement; superconducting coils; thermal stresses; transformer windings; vibrations; 77 to 20 K; AC loss measurements; closed-cycle Cryomech GB-37 cryocooler; cryocooled sample; cryostat; high-temperature superconductor coils; measurement procedure; short AC current pulses; subscale transformer winding pairs; superconductor measurements; thermal stresses; vibration; Current measurement; High temperature superconductors; Loss measurement; Pulse transformers; Superconducting coils; Temperature measurement; Thermal conductivity; Thermal stresses; Windings; Wounds;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
