Product Introduction TKBB-S Transformer Ratio Tester is specially designed for three- phase transformer in power system especially for transformer of type Z winding and other transformers whose zero-load current is relatively high.Transformer turns ratio test is very important in order to find out the transformer has the right ratio corresponding on its rated voltage in primary and secondary. TKBB-S is single phase, automatically test set specially designed for turns ratio, phase shift and excitation current measurements of power, distribution and instrument transformer. The tester has wide testing range fast testing speed favorable repeatability flexible data processing convenient connection complete protection easy learning and convenient operation