50 Hz current-dependent losses of Bi2Sr2Ca1Cu2O8+x/Ag wires

50 Hz current-dependent loss measurements were carried out at 4.2 K on short straight samples of Bi2Sr2Ca1Cu2O8+x /Ag wires having high critical current densities of up to 1.5x104 A/cm2 at 26 T. The ac power losses vary proportional to the square of the transport current which is not consistent with the simple Bean model. On the other hand the losses depend linearly on the frequency of the alternating current which would be compatible with hysteresis as the dominant loss mechanism. Loss values are found to be rather high and are not strongly influenced by bias magnetic fields up to 1 T. Several effects may contribute to the loss enhancement and its current dependence, however the reason for this behavior remains to be clarified