Alternating current losses in stacks of powder-in-tube-processed Bi2Sr2Ca2Cu3O10/Ag tapes were measured in perpendicular magnetic fields and compared with calculated hysteresis losses based on the critical-state model. Four main factors had to be taken into account for the calculations of the losses: (1) the inclusion of the area of the Ag sheath in determining the critical-current densities of the stacks, (2) the zero-applied-field critical currents Ic⊥(0) with truly perpendicular fields only, not the standard self-field critical current IcS(0), and (3) the field-dependent critical current Ic(H), e.g., the Kim’s model, and (4) the subtraction of the frequency-dependent losses at very high fields. With these considerations, the agreement between the calculated and the measured values of the losses is excellent for fields beyond the full-penetration fields. However, these factors did not totally account for the low-field losses.

ac losses for a stack of B i 2 2 2 3 l A g were determined as a function of the angle between the applied ac magnetic field and the tape face. The results were compared with the ac losses calculated using the Bean critical-state model. Although the general qualitative behavior of the calculated 1 o s s as a function of the angle was in accord with the measured values, the model failed significantly i n quantitative predictions of the losses.

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