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TTRM-301 / TTRM-302 Three-Phase Transformer Ratio Meters

The TTRM-301 and TTRM-302 are high-performance three-phase transformer turn ratio meters designed for rapid and precise testing of power transformers, distribution transformers, and special vector-group machines.
These instruments perform simultaneous HV–LV phase testing, providing measurements of turns ratio, phase displacement, polarity, vector group, and excitation current with exceptional accuracy and stability.
The TTRM-302 is the advanced variant offering extended ranges, enhanced accuracy, and higher noise immunity for demanding substation environments.

Model Options

Key Features

  • Simultaneous 3-phase ratio measurement

  • Automatic vector group identification (IEC & ANSI)

  • Measures:

    • Turns Ratio

    • Phase Angle

    • Polarity

    • Excitation Current

  • TTRM-302 includes:

    • Extended ratio range

    • Higher accuracy

    • Advanced DSP filtering for noisy substations

  • Auto wiring-error detection

  • Large LCD display with vector diagram output

  • Internal memory + USB export

  • Rugged design for field use

Technical Specifications

Parameter TTRM-301 TTRM-302
Ratio Range 0.8–20,000:1 0.8–50,000:1
Accuracy ±0.1% ±0.05%
Phase Angle Range 0–360° 0–360°
Polarity Automatic Automatic
Test Voltage 8–120 V AC 8–120 V AC
Excitation Current Up to 5 A Up to 10 A
Vector Groups All All (improved auto-detection)
Display Backlit LCD Backlit LCD
Memory Internal + USB Internal + USB
Power Supply 220 V AC 220 V AC
Weight ~14 kg ~16 kg

Standard Accessories

  • Three-phase HV test leads

  • Three-phase LV test leads

  • Ground cable

  • USB data cable

  • Power cable

  • Carry/transport case

  • User manual & calibration certificate

Applications

  • Three-phase turn ratio testing of power transformers

  • Vector group verification & polarity testing

  • Transformer factory testing & routine QA

  • Substation commissioning & maintenance

  • Diagnostic evaluation of ageing transformers

Optional Add-Ons

  • Extended HV/LV cable sets (10–30 m)

  • Ruggedized wheeled case

  • On-site printer kit

  • PC waveform & history-tracking software

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