A mechanism causing an additional AC loss in a large CICC coil

Hamajima, T.; Yoshida, Masafumi; Shimamura, H.; Harada, N.; Tsuda, Makoto; Hanai, S.; Satow, T.

doi:10.1109/77.920211

Cited by 9 publications

(11 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In a previous paper we proposed a following mechanism forming a long loop with long time constant [4]. If one strand on the surface of a sub-cable contacts with the other strand on the surface of the adjacent sub-cable, the two strands must encounter each other again at the LCM distance, and thereby result in forming a pair of a long loop, as indicated conceptually in Fig.…”

Section: B a Mechanism Causing The Long Loopsmentioning

confidence: 97%

“…The term "irregular AC loss" is defined as a coupling loss, which is not proportional to the twisting pitch squared. The irregular AC losses with long time constants were typically observed in a Japanese SMES model coil that was tested at Japan Atomic Energy Research Institute (JAERI) and Lawrence Livermore National Laboratory (LLNL) [1]- [4]. Main parameters of the SMES model coil are listed in Table I [ 14].…”

Section: Introductionmentioning

confidence: 99%

“…We proposed a mechanism forming the long loops [4]. The CIC conductor is composed of several staged sub-cables.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Long time constants of irregular AC coupling losses in a large superconducting coil

Hamajima

Harada

Satow

et al. 2002

IEEE Trans. Appl. Supercond.

Self Cite

View full text Add to dashboard Cite

A large superconducting coil wound with Cable-inConduit (CIC) conductor caused an irregular AC loss that cannot be estimated from short conductor sample test results. It was confirmed that the irregular AC loss was generated by long current loops in the CIC conductor. We proposed a mechanism forming the long loops. The CIC conductor is composed of several staged sub-cables. If one strand on the surface of a sub-cable contacts with the other strand on the surface of the adjacent sub-cable, the two strands must encounter each other again at LCM (Least Common Multiplier) distance of all staged cable pitches and thereby result in forming a pair of a long loop. We measured cross over point contact resistance between two strands making the long loop. The calculated time constants of the long loops were shorter than the observed ones. We orderly labeled all strands in a real CIC conductor, disassembling carefully the cable after peeling the conduit. It was found that the strands in a triplet were widely displaced from their original positions, and thereby their contacting lengths became longer than cross over ones to form line contacts. This fact can make the time constant of the loop longer and hence can explain the observed long time constants.

show abstract

Section: B a Mechanism Causing The Long Loopsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Long time constants of irregular AC coupling losses in a large superconducting coil

Hamajima

Harada

Satow

et al. 2002

IEEE Trans. Appl. Supercond.

Self Cite

View full text Add to dashboard Cite

show abstract

“…According to the mechanism proposed previously [4], the pair of strands on the semi-final stage of the cable can make the largest loop. We can treat the largest loop as a long parallel conductor and calculate its inductance as follows:…”

Section: Irregular Coupling Ac Lossesmentioning

confidence: 99%

“…The loops that cause irregular AC losses have characteristics of various long time constants and large number. We propose a new mechanism whereby long loops are formed to satisfy the above characteristics [4]. The CIC conductor is composed of several sub-cable stages.…”

Section: Irregular Ac Losses With Long Time Constants In Large Cable-mentioning

confidence: 99%

Irregular AC losses with long time constants in large cable-in-conduit conductors

Hamajima

Kakusho

Hoashi

et al. 2003

IEEE Trans. Appl. Supercond.

Self Cite

View full text Add to dashboard Cite

A large superconducting coil wound with Cable-in-Conduit (CIC) conductor causes both irregular AC losses that cannot be estimated from short conductor sample test results, and regular AC losses that are proportional to cable twisting pitch squared. We proposed a mechanism forming loops that generated the irregular losses. The CIC conductor is composed of several stages of sub-cables. If one strand on the surface of a sub-cable contacts another strand on the surface of the adjacent sub-cable, the two strands must encounter each other again at the LCM (Least Common Multiplier) distance of all staged cable pitches, and thereby a long loop is formed. We orderly labeled all strands in CIC conductors for the SMES and the LHD. It was found that strands in a triplet were widely displaced from their original positions on one cross section, but contacted each other tightly on the other cross section. This fact suggests that the loop with the large displaced strand links irregularly with external field so that the loops cause the irregular AC losses. Moreover, it indicates that a contacting length of the large displaced strands can be quite long, giving rise to a low contact resistance for the loop, and leading to the long time constants. It is believed that the widely displaced strand are inherent in a CIC conductor. It was demonstrated that the strand surface coated with CuNi was effective to suppress the irregular AC losses.

show abstract

Coupling loss with long time constants due to large displacement of strands in a large CIC conductor

Yagai

Sato

Tsuda

et al. 2006

Fusion Engineering and Design

View full text Add to dashboard Cite

A mechanism causing an additional AC loss in a large CICC coil

Cited by 9 publications

References 10 publications

Long time constants of irregular AC coupling losses in a large superconducting coil

Long time constants of irregular AC coupling losses in a large superconducting coil

Irregular AC losses with long time constants in large cable-in-conduit conductors

Coupling loss with long time constants due to large displacement of strands in a large CIC conductor

Contact Info

Product

Resources

About