Current ripple effect on superconductive d.c. critical current measurements

✍ Scribed by L.F. Goodrich; S.L. Bray

• Publisher: Elsevier Science
• Year: 1988
• Tongue: English
• Weight: 753 KB
• Volume: 28
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/0011-2275(88)90137-3

✦ Synopsis

The effect of current ripple or noise on d c critical current measurements was systematically stud~ed Measurements were made on multddamentary Nb T~ superconductor A Iow-no~se, battery-powered current supply was required m th~s study m order to make the pure d c critical current measurements Also, an electromc c)rcu~t that stimulates a superconductor's general current voltage charactenst~c was developed and used as an analysis tool In order to make critical current measurements ~n wh)ch current npple was present, the battery supply was modff)ed to allow the introduction of controlled amounts of a c ripple In general, ripple ~n a current supply becomes more s~gmflcant in current supphes rated above 500 A because effectwe f)ltermg ~s ddficult The effect of current ripple ~s a reduction m the measured d c crmcal current, however, ripple of sufficient amphtude can result m arbitrary measurement results The results of th)s work are general and quantitatively apphcable to the evaluat)on of critical current data and measurement systems A theoretical model was developed to further support and explmn the ripple effect An unexpected benefit of this work was a more precise method for general cnt~cal current data acqu)sltlon Problems common to all large conductor critical current measurements are discussed