The PATTR-03A determines the transformer turns-ratio using the IEEE C57.12.90 measurement method. The PATTR-03A generates and outputs an excitation test voltage to the transformer’s three primary windings. The induced secondary voltage is sensed and the transformer turns ratio is calculated. The PATTR-03A can measure turns-ratios from 0.8 to 15,000. The transformer turns-ratio, excitation current, and phase-angle readings are displayed on the unit’sLCD screen. The built-in transformer type detection feature allows the PATTR-03A to detect and test 130 transformer types defined by ANSI, CEI/IEC and Australian standards.