This item is a great condition used Vanguard ATRT-01B Automatic Transformer Ratio Tester. Calibrated to NIST Traceable Standards on August 26, 2026. Includes circuit breaker leads, standard power cable, and NIST traceable calibration certificate. All pictures are of the actual unit and accessories.
This item comes with a 6 Month (180 day) warranty. Every pre-owned unit we offer goes through meticulous inspection to guarantee its reliability and durability.
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Vanguard ATRT-01B Automatic Transformer Ratio Tester NIST Calibrated
Product Information
The Vanguard ATRT-01B is a portable, microprocessor-based automatic transformer turns-ratio tester designed for fast, accurate field testing of transformers. It measures the turns ratio by applying a controlled test voltage to the transformer winding and measuring the induced voltage on the opposite winding, following the ANSI/IEEE C57.12.90 measurement method. The unit can also display winding polarity, phase angle, excitation current, and turns-ratio percentage error, making it useful for verifying transformer condition and identifying winding or connection issues.
The ATRT-01B version adds rechargeable battery operation, allowing up to 4 hours of continuous testing per charge, while also supporting AC power. It is designed for portable, standalone operation but can also be computer-controlled through its RS-232 interface. The tester supports a very wide 0.8 to 15,000:1 turns-ratio range and offers selectable 4 VAC and 40 VAC test voltages for different transformer applications.
Specifications and Info
- Type: Automatic, single-phase transformer turns-ratio tester
- Turns Ratio Range: 0.8 to 15,000:1
- Test Voltages: 4 VAC and 40 VAC
- Turns-Ratio Accuracy: Up to ±0.1% depending on range and test voltage
- Measurement Method: ANSI/IEEE C57.12.90
- Phase Angle: 0–360°, ±0.2°
- Polarity: In-phase / out-of-phase indication
- Excitation Current: Displays transformer excitation current
- Power: 90–240 VAC, 50/60 Hz or rechargeable SLA battery
- Battery Runtime: Up to 4 hours continuous operation
- Display: 4-line × 20-character LCD
- Computer Interface: RS-232C
