Experimental Study of AC Losses in a Rutherford Type Cable
This paper describes measured AC losses of NbTi Rutherford type cable when the wide side of the cable is parallel to the field variation. In the case of a Rutherford type cable, the orientation of the cable in the magnetic field is an important factor for the interstrand coupling loss which can be dominant over other AC losses such as hysteresis loss or intrastrand coupling loss. A calorimetric method was used to quantify experimentally the AC losses of the cable. The measurement results were essential to the thermal design of a superconducting pulse coil set for use in stability experiments on the TPX (Tokamak Physics Experiment) subsize conductors. AC losses were also measured with transport current to see its effect on this loss. The transport current effect on the interstrand coupling loss was generally negligible when the 0.086 T ripple field at 7.5 Hz was applied to the cable on top of the dc bias field. However, when the field was varied in the slow continuous triangular wave between 0 to 7 T, the AC loss increased noticeably due to transport current.
KeywordsLorentz Force Ramp Rate Transport Current Hysteresis Loss Coupling Loss
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