TURA-01 is designed to measure the turns ratio of single and three-phase transformers. TURA-01 has a fast, easy, and accurate TTR measurement features for current, voltage and power transformers using its user-friendly software. It’s one of the most accurate devices with its wide range (0.8 to 33,000) ratio measurement capability and high precision (0.08 %). https://www.hightest.co.uk/product-cat/single-phase-ttr/