This paper is focused on the turn-to-turn contact resistance as a major source of the characteristic resistance of no-insulation YBCO pancake coil. Usually, the characteristic resistance of the coil is calculated by measuring decay time constant. However, we identify that the turn-to-turn contact resistance is not a constant value and changes with time. In order to verify this, one single pancake NI HTS coil consisting of 27 turns were fabricated with winding tension carefully maintained at a constant level. Through charge, discharge and sudden tests under time-varying, we obtain curves of the axial field at the centre, coil end-to-end voltage and an output current of power supply. In this paper, results show that the turn-to-turn contact resistance of NI coil varies with the time.

本文的重点是匝间接触电阻，它是无绝缘YBCO煎饼线圈特征电阻的主要来源。通常，通过测量衰减时间常数来计算线圈的特征电阻。但是，我们发现匝间接触电阻不是恒定值，而是随时间变化的。为了验证这一点，制造了一个由27匝构成的薄煎饼NI HTS线圈，并小心地将绕组张力保持在恒定水平。通过随时间变化的充电，放电和突然测试，我们获得了中心轴向磁场，线圈端到端电压和电源输出电流的曲线。本文结果表明，NI线圈的匝间接触电阻随时间变化。