Vanguard ATRT-01B S3 Single-Phase Transformer Turns Ratio Tester | Ratio 0.8–15,000, 4/40 Vac, battery or mains, 4.3 kg

Vanguard ATRT-01B S3 Single-Phase Transformer Turns Ratio Tester: Battery or Mains

Overview

The ATRT-01B S3 is Vanguard's fourth-generation microprocessor-based automatic single-phase transformer turns ratio tester. It determines the ratio by measuring no-load winding voltages per the IEEE C57.12.90 method and self-adjusts before each measurement. A test voltage of 4 Vac or 40 Vac can be selected, and it displays ratio error percentage, winding polarity, phase angle and excitation current. It runs on battery or mains power and can be used while charging.

Key Specifications

• Measurement method: ANSI/IEEE C57.12.90
• Ratio range and accuracy: 0.8–15,000; 40 Vac: 0.8–1,999 0.1%, 2,000–3,999 0.25%, 4,000–15,000 1%
• Test voltage: 4 Vac @ 300 mA, 40 Vac @ 70 mA
• Phase angle and polarity: 0–360°, ±0.2°; in-phase/out-of-phase indication
• Excitation current: 0–2 A; 2% of reading (±1 mA)
• Power: 90–240 Vac; lead-acid battery, approx. 4 hours of continuous use per charge
• Interface and storage: RS-232C; Windows analysis software included; 128 internal records (33 readings each), up to 999 records on USB flash drive
• Dimensions and weight: 30.4 × 25.4 × 20.3 cm; 4.3 kg

Applications

• On-site ratio testing in substations and at project sites without mains power.
• Ratio and polarity checks of single-phase and three-phase transformers (phase by phase).

Specifications per the specification table on the Vanguard ATRT-01B S3 product page (doble.com, retrieved 2026-10-23).