Eddy current self-field loss in Bi-2223 tapes with a.c. transport current

The a.c. self-field loss in Bi-2223/Ag and Ag-alloy tapes with different filament number has been measured in the range 59–2500 Hz. The different loss contributions–hysteretic, eddy current and flux–creep resistive loss (near I c) are quantitatively dissociated due to their different frequency dependence and the broad frequency measurement range. The relative weight of eddy current losses is found to be inversely proportional to the applied current ratio—the higher I p/ I c, the less is their contribution. Shown are the frequency limits, beyond which eddy current loss has significant and afterwards governing contribution to the total a.c. loss in self-field. The distribution of power dissipation in the metal sheath is obtained by software simulation. A comparison is made between the measured, simulated and theoretically calculated eddy current loss. Investigated is the effect of the sheath geometry and resistivity in reducing the eddy current loss in the measured and simulated tapes.