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TRM-25 / TRM-25+ Transformer Ratio Meter

The TRM-25 Series is a precision transformer turns ratio meter designed for testing power and distribution transformers of all voltage classes.
It delivers highly accurate ratio, phase angle, polarity, and excitation measurements with fast test cycles and automated analysis. The TRM-25+ adds enhanced accuracy, wider ranges, and advanced filtering for high-interference substation environments.

Model Options

Key Features

  • Measures turns ratio, phase angle, polarity, excitation current

  • Automatic test sequencing with fast measurement time

  • High accuracy digital measurement engine

  • TRM-25+: improved accuracy, expanded ratio range & stronger noise immunity

  • Fully automatic connection validation & safety interlocks

  • Built-in memory for test data + USB export

  • Color LCD screen with clear vector indication

  • Lightweight, rugged and ideal for field transformer testing

Technical Specifications

Parameter TRM-25 TRM-25+
Ratio Range 0.8–20,000:1 0.8–50,000:1
Accuracy ±0.1% ±0.08%
Phase Angle 0–360° 0–360°
Polarity Check Automatic Automatic
Test Voltage 8–120 V AC 8–120 V AC
Excitation Current Measure up to 5 A Measure up to 10 A
Display Color LCD Color LCD
Memory Internal + USB Internal + USB
Power Supply 220 V AC 220 V AC
Weight ≈ 7 kg ≈ 8 kg

Standard Accessories

  • High-voltage and low-voltage test leads

  • Ground cable

  • USB cable

  • Power cable

  • Soft carrying case

  • User manual + calibration certificate

Applications

  • Power transformer turn ratio testing

  • Distribution transformer QC and maintenance

  • Vector group verification

  • Polarity and phase displacement testing

  • Substation commissioning

Optional Accessories

  • Extended test lead set (10–30 m)

  • HV shielded leads

  • Printer kit for instant paper reports

  • Rugged hard-case upgrade

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