The ATRT-01B S3 is Vanguard’s fourth generation, micro-processor based, single phase, automatic transformer turns-ratio tester. The ATRT-01B S3 uses the IEEE C57.12.90 measuring method to determine the transformer turns-ratio. The transformer turns-ratio is determined by precisely measuring the voltages across the unloaded transformer windings. The ATRT-01B S3’s measuring circuitry self adjusts before each measurement to ensure turns-ratio accuracy. Two selectable test voltages, 4Vac and 40Vac, offer flexibility in testing different types of transformers.

The Vanguard Instruments ATRT-03 S2 is the third generation, microprocessor-based, automatic, three phase, transformer turns-ratio tester. This light weight, rugged, portable unit is designed for transformer testing at utility power substations.

The Vanguard Instruments Company Model ATRT-03A Series 2 is Vanguard's third generation, microprocessor-based, automatic, three phase transformer turns-ratio tester.

The ATRT-03A Series 2 determines the transformer turns ratio using the IEEE C57.12.90 measurement method. The ATRT-03A Series 2 generates and outputs an excitation voltage to the three transformer primary winding. The included secondary voltage is sensed and the transformer turns ratio is calculated.

The ATRT-03B S2 is Vanguard’s third generation, microprocessor-based, automatic, three phase, transformer turns-ratio tester. This lightweight and rugged portable unit is designed for transformer testing at utility power substations.

The LTC Controller is an accessory which is used with the Models ATRT-03, ATRT-03A, and ATRT-03B units. The LTC Controller enables the user to remotely raise or lower a transformer tap by interfacing with the transformer load tap-changer controller.