Phenix, USA Pattr-03 Automatic Transformer Turn Ratio(TTR) test set Phenix Technologies?, USA Model PATTR-03 is a microprocessor-based, automatic, single and three-phase transformer-turns ratio tester. The unit is portable, lightweight, and ruggedly built for testing transformers in the field or in a laboratory setting. THE PATTR-03 determines transformer turns ratio by precisely measuring the voltages across unloaded transformer windings and then displays the ratio of these voltages (ratios range from 0.8 to ?15,000). The unit self-calibrates before each measurement to ensure turn ratio accuracy. The PATTR-03 requires no calibration or temperature compensation. In addition to measuring a transformer?s turns ratio, the PATTR-03 also measures a transformer?s excitation current and its phase angle. It displays the turns-ratio, excitation current, and turns ratio accuracy on a 20-character by 4-line back-lighted LCD.