Description DTBC-9909 is designed to measure transformer capacity and power loss of open circuit and short circuit. It use advanced DSP and multiple high performance A/ D converter to synchronously sample and process AC signals, so as to solve the difficult problem of synchronous sampling and calculating low power factor and multiple signal under utility power condition. The test set has single-phase test mode, so as to test single-phase fault or perform test under lacking three-phase power supply. Using external VT and CT, the test set can be applied to over range transformers.