Vanguard TRF-100 Three-Phase Transformer Turns Ratio Tester | Ratio 0.8–50,000, 4/40/100 Vac, phase angle and excitation current

Vanguard TRF-100 Three-Phase Transformer Turns Ratio Tester: 0.8–50,000

Overview

The TRF-100 is Vanguard's third-generation microprocessor-based automatic three-phase transformer turns ratio tester. It determines the ratio by measuring no-load winding voltages per the IEEE C57.12.90 method and self-calibrates before each measurement, requiring no adjustment or temperature compensation. It recognizes 130 three-phase transformer types defined by ANSI, IEC and Australian standards, and measures phase angle and excitation current at the same time.

Key Specifications

• Measurement method: ANSI/IEEE C57.12.90
• Ratio range: 0.8–50,000
• Ratio accuracy (typical): 40/100 Vac: 0.8–1,000 ±0.05%, 1,001–4,000 ±0.1%, 4,001–15,000 ±0.25%, up to 50,000 ±0.5%; 4 Vac: 0.8–1,000 ±0.08%
• Test voltage: 4 Vac @ 1.0 A, 40 Vac @ 0.6 A, 100 Vac @ 0.1 A
• Excitation current: 0–2 A; ±1 mA ±2% of reading
• Phase angle: 0–360°; ±0.2°
• Display and storage: Backlit LCD, 20 characters × 4 lines; 1,000 transformer records, 128 test plans
• Interface and printing: USB; optional built-in 4.5-inch thermal printer; Windows analysis software included
• Power and dimensions: 100–120 or 200–240 Vac; 43.2 × 17.8 × 33.0 cm; 6.4 kg

Applications

• Ratio, polarity and phase acceptance testing of substation and distribution transformers.
• Transformer preventive maintenance and fault diagnosis.

Specifications per the specification table on the Vanguard TRF-100 product page (doble.com, retrieved 2026-10-23).