A general treatment of losses in multifilamentary superconductors

Campbell, A.M.

doi:10.1016/0011-2275(82)90015-7

Cited by 221 publications

(170 citation statements)

References 11 publications

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“…They were found to increase by a factor of four when the frequency was doubled from 55 to 110 Hz, indicating that the losses from induced currents dominated the loss at 55 Hz [1]. An increase by a factor of just under two occurred, however, when the transport current frequency was increased from 110 to 200 Hz, indicating that the induced currents had saturated the superconductor, causing further losses to behave more like a penetration type loss mechanism and, therefore, hysteretic-like in nature [10].…”

Section: E Ac Losses Due To Transport Current and Applied Fields In mentioning

confidence: 99%

“…T HE TOTAL ac losses at power frequencies of superconductors in the presence of an ac magnetic field, an ac transport current, a dc background field, and various combinations of these have been measured [1]- [5]. For the most part, however, these losses have been determined on short pieces of tape, and assumptions have been made about how these measurements can predict the ac losses in working devices.…”

Section: Introductionmentioning

confidence: 99%

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Determination of the AC losses of Bi-2223 HTS coils at 77 K at power frequencies using a mass boil-off calorimetric technique

Darmann¹,

Dou

Cook

2003

IEEE Trans. Appl. Supercond.

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Abstract-A mass boil-off measurement system has been used to accurately measure and characterize the ac loss of high-temperature superconductor (HTS) coils at frequencies between 50 and 200 Hz, and in applied ac fields of up to 0.04 T. The mass boil-off calorimeter incorporated a glass cryostat, a copper field coil, and two mass flow meters. The response of the gas flow to a step change in the applied magnetic field was found to have a time constant of about 600 s. Under suitable experimental conditions, it was possible to measure the ac losses of coils with an accuracy of 0.3 W. The ac loss characteristics of an HTS pancake and two HTS solenoid coils are presented and the accuracy of mass flow calorimetry in liquid nitrogen is reported on.

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Section: E Ac Losses Due To Transport Current and Applied Fields In mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Determination of the AC losses of Bi-2223 HTS coils at 77 K at power frequencies using a mass boil-off calorimetric technique

Darmann¹,

Dou

Cook

2003

IEEE Trans. Appl. Supercond.

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show abstract

“…AC field is applied perpendicular to the wide side of the cable. This value can be rescaled for new strand's and cable's geometries according to [5], [6].…”

Section: Ac Loss Estimationmentioning

confidence: 99%

Design of the HTS Fusion Conductors for TF and CS Coils

Bykovsky

Uglietti

Wesche

et al. 2016

IEEE Trans. Appl. Supercond.

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Abstract-The main electrical and mechanical requirements for the LTS fusion conductors of DEMO are retained as a starting point for the development of HTS fusion cables. Based on the HTS coated conductor technology, a flat cable design was proposed by CRPP Swiss Plasma Center (SPC) using the strands made of twisted stack of tapes soldered into copper profiles. Analytical modeling of the cable geometry is developed and presented in this work. The model was used to estimate various properties of cable. Addressing the issue of bending strain and related performance degradation, an optimization model of the cable properties was built, which allows to best fulfill the cable requirements. Design options are developed for both toroidal field (TF) coils operating at 63 kA and central solenoid (CS) coils operating at 50 kA. Paying attention to the DC and pulsed operation of the TF and CS coils, proposals for the design of the forced-flow HTS conductors are reported and discussed for each type of the coils.

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“…28,29 The electromagnetic loss in superconductors consists of hysteresis and coupling loss. The coupling loss time constant is derived from the initial slope of the loss curve ͓͑J/m 3 ͒, energy loss per cycle versus applied sweep rate of identical amplitude͔, assuming that the hysteresis loss per cycle at low excitation is independent from the sweep rate.…”

Section: B Current Transfer Length and N Valuementioning

confidence: 99%

Critical current measurement with spatial periodic bending imposed by electromagnetic force on a standard test barrel with slots

Nijhuis

Wessel

Ilyin

et al. 2006

Review of Scientific Instruments

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We have developed and validated a straightforward and fast method to investigate the response of technological superconducting strain sensitive wires ͑e.g., Nb 3 Sn͒ to a spatial periodic bending strain. In the present concept of cabled superconductors for application in nuclear fusion reactors the wires are twisted and cabled in several stages. When subjected to transverse electromagnetic forces after charging the magnet, the individual strands are subjected to spatial periodic bending with wavelengths in the order of 5 -10 mm. Several apparatuses are presently under development to study the effect of bending on the transport properties, i.e., the voltage-current transition in terms of critical current ͑I c ͒ and n value. We propose a supplementary simple method to investigate the influence of bending strain by using a spatial periodic wire support on a broadly used standard I c measurement barrel in combination with a Lorentz force. The bending force ͑BI͒ is varied by changing the applied field B. The peak bending strain in the Nb 3 Sn filaments is determined by the amplitude of the bending deflection, which is deduced from the mechanical axial tensile stress-strain properties of the wire. Three different spatial periodic wavelengths are applied and the results are in good agreement with the predictions. In addition we found a good agreement with results obtained by a more advanced experiment, named TARSIS, which is described briefly. The "barrel-with-slots" method can be applied easily and straightforward with minor effort and cost in laboratories having a standard I c measurement facility for superconducting wire.

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A general treatment of losses in multifilamentary superconductors

Cited by 221 publications

References 11 publications

Determination of the AC losses of Bi-2223 HTS coils at 77 K at power frequencies using a mass boil-off calorimetric technique

Determination of the AC losses of Bi-2223 HTS coils at 77 K at power frequencies using a mass boil-off calorimetric technique

Design of the HTS Fusion Conductors for TF and CS Coils

Critical current measurement with spatial periodic bending imposed by electromagnetic force on a standard test barrel with slots

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