The ATRT-03 determines the transformer turns-ratio using the IEEE C57.12.90 measurement method. The transformer turns-ratio (ranging from 0.8 to 15,000) is determined by precisely measuring the voltages across the unloaded transformer windings. To ensure accuracy, the ATRT-03’s measuring circuitry self-calibrates before each measurement. It requires neither adjustment nor temperature compensation. The ATRT-03’s turns-ratio measurement accuracy is 0.1% or better.
The ATRT-03 can perform a specific test for each transformer type (such as single phase, delta to Y, Y to delta, delta to delta, or Y to Y) without the need to switch test hookup cables. Also, the unit’s automatic transformer phase detection feature can detect different transformer vector diagrams.
The ATRT-03 can automatically detect and test 67 transformer types defined by ANSI, CEI/IEC and Australian standards.To prevent an accidental wrong test-lead hook-up (e.g., when the operator reverses H and X leads), the ATRT-03 outputs a low-level test voltage to verify the hook-up condition before applying the full test voltage to the transformer. Three test voltages (8 Vac, 40 Vac, 100 Vac) allow the ATRT-03 to test CT’s and PT’s, as well as power transformers.
In addition to measuring a transformer’s turns-ratio, the ATRT-03 can also measure a transformer’s excitation current (in milli-amperes) and its winding phase angle.