Sammendrag
The MgB2 superconductor is an attractive choice for many high-current DC applications, particularly for its low cost compared to e.g. YBCO, and the higher operating temperature than the low-temperature superconductors. To extend the operating range to include also AC applications, the AC losses need to be determined and a path towards a low-loss conductor needs to be established and verified. To accomplish this development, systematic and reliable measurements of the losses are essential. In this paper we present AC loss measurement results on non-twisted MgB2 wires with titanium and copper-nickel matrices. 50 Hz AC losses were measured calorimetrically in applied magnetic fields, with transport currents, and with combinations of both. The temperature range was between 25 K and $T_{c}$, the magnetic field was varied up to 300 mT, and the transport current up to 113 A. The measurement results are used as a basis to discuss the necessary AC loss reduction steps in MgB2 superconductors. © Copyright 2013 IEEE - All rights reserved.