变压器直流电阻测试仪的测量方法

Measuring method of transformer DC resistance tester

测量直流电阻是变压器试验中的一个重要项目。通过测量，可以检查出设备的导电回路有无接触不良、焊接不良、线圈故障及接线错误等缺陷。在中、小型变压器的实际测量中，大多采用直流电桥法，当被试线圈的电阻值在１欧以上的一般用单臂电桥测量，１欧以下的则用双臂电桥测量。在使用双臂电桥接线时，电桥的电位桩头要靠近被测电阻，电流桩头要接在电位桩头的上面。测量前，应先估计被测线圈的电阻值，将电桥倍率选钮置于适当位置，将非被测线圈短路并接地，然后打开电源开关充电，待充足电后按下检流计开关，迅速调节测量臂，使检流计指针向检流计刻度中间的零位线方向移动，进行微调，待指针平稳停在零位上时记录电阻值，此时，被测线圈电阻值＝倍率数×测量臂电阻值。测量完毕，先开放检流计按钮，再放开电源开关

Measuring DC resistance is an important item in transformer test. By measuring, it is possible to check the electrical conduction loop of the equipment, such as bad contact, bad welding, coil fault and wiring fault. In the actual measurement of medium and small transformers, the DC bridge method is mostly adopted. When the resistance of the tested coil is above 1 euro, the measurement is made by single arm bridge, and the measurement of 1 euro is measured by double arm bridge. When using two arm bridge connection, the potential pile head of the bridge should be close to the resistance measured, and the current pile head should be connected to the top of the potential pile head. Before the measurement, should first estimate the measured value of the coil resistance, the bridge button arranged at the proper position rate, non tested coil short-circuit and grounding, then turn on the power switch for charging, after charging press galvanometer switch, quickly adjust the measuring arm, the galvanometer pointer fine-tuning to zero line direction of middle scale galvanometer the move, record the resistance value, until the pointer stopped at zero steady at this moment, the measured coil resistance ratio = x arm resistance measurement. After the measurement, and then release the button to open the galvanometer, the power switch