Transformer Turns Ratio (TTR) testing is one of the most important diagnostic tests performed during transformer manufacturing, commissioning, preventive maintenance, and troubleshooting. A reliable turns ratio tester not only verifies the winding ratio but also helps identify winding defects, tap changer problems, incorrect connections, and transformer vector groups.

DV Power offers two powerful TTR product families:

• TRT Standard Series
• TRT Advanced Series

Both product lines provide highly accurate transformer turns ratio measurements, but they are designed for different users and applications. Understanding the differences can help engineers select the most suitable instrument for their testing requirements.

Why Transformer Turns Ratio Testing Matters

A transformer's turns ratio directly determines the voltage transformation between the primary and secondary windings.

Incorrect turns ratio measurements may indicate:

• Shorted turns
• Open windings
• Tap changer problems
• Incorrect winding connections
• Manufacturing defects
• Transformer damage after transportation

Modern TTR testing has evolved far beyond simply measuring voltage ratios. Today's instruments also evaluate excitation current, vector group, phase displacement, magnetic balance, and can even automate OLTC testing.

DV Power has incorporated these capabilities into both the TRT Standard and TRT Advanced Series.

What Both Series Have in Common

Whether you choose the Standard or Advanced Series, both offer professional transformer diagnostic capabilities, including:

• High-accuracy turns ratio measurement
• Excitation current measurement
• Phase shift measurement
• Automatic vector group detection
• Magnetic balance testing
• Three-phase transformer testing
• Three-phase autotransformer testing
• Built-in OLTC control
• DV-TR software support
• Ratio measurement up to 50,000
• Accuracy up to ±0.03%

For many utilities and service companies, either series is capable of handling routine transformer testing.

TRT Standard Series

The TRT Standard Series is designed for users who need a dependable, professional transformer turns ratio tester while maintaining excellent portability and value.

Available models include:

• TRT03 Series
• TRT33 Series
• TRT63 Series

Depending on the model, the Standard Series provides:

• Single-phase output
• True three-phase output (selected models)
• Test voltage from 1 V to 250 V AC
• LCD graphical display
• Lightweight portable design

The Standard Series is ideal for:

• Distribution transformers
• Power transformers
• Routine maintenance
• Commissioning
• Field service engineers
• Utilities
• Industrial maintenance

Its traditional LCD interface provides straightforward operation while still supporting advanced diagnostic measurements.

TRT Advanced Series

The TRT Advanced Series represents DV Power's latest generation of transformer turns ratio testers.

Available models include:

• TRT100
• TRT250
• TRT400
• TRT500

Compared with the Standard Series, the Advanced Series introduces several important improvements.

Higher Test Voltage

One of the biggest upgrades is the available test voltage.

Higher test voltage generally improves measurement stability and accuracy on larger power transformers.

Large Touch Screen Interface

Perhaps the most obvious difference is the user interface.

The Advanced Series features:

• 10.1-inch touch screen (TRT500)
• 7-inch touch screen (other Advanced models)
• Modern graphical interface
• Easier navigation
• Improved report review
• Faster configuration

Compared with the LCD display of the Standard Series, the touch interface significantly improves field usability.

Automatic Test Mode

Another major advantage is the built-in Automatic Test Mode.

Instead of manually changing every tap position, technicians can:

• Load a stored test template
• Automatically control the OLTC
• Execute all turns ratio measurements
• Save every result automatically

For transformers with many tap positions, this feature can save considerable testing time while reducing human error.

Test Templates

The Advanced Series allows technicians to create reusable test templates directly inside the instrument.

This is particularly useful for:

• Utility maintenance programs
• Repetitive transformer fleets
• Production testing
• Factory acceptance testing
• Service companies

Instead of configuring each transformer from scratch, technicians simply load the appropriate template.

CVT Testing Capability

The TRT500 can also be expanded with the optional CVT20 extension transformer, increasing the output voltage up to 5 kV AC.

This allows testing of:

• Capacitive Voltage Transformers (CVTs)

This capability is unique to the TRT Advanced Series.

Side-by-Side Comparison

Which Series Should You Choose?

The TRT Standard Series is an excellent choice if you need:

• Routine transformer maintenance
• High accuracy
• Portable equipment
• Cost-effective testing
• Utility field service
• Industrial maintenance

The TRT Advanced Series is the better solution if you want:

• Faster testing
• Maximum automation
• Touch-screen operation
• Automatic OLTC testing
• Large power transformer testing
• CVT testing
• Reduced operator workload
• Higher productivity

Final Thoughts

Both DV Power transformer turns ratio tester families deliver excellent measurement accuracy and comprehensive transformer diagnostics.

The TRT Standard Series focuses on providing a reliable and economical testing platform suitable for most transformer maintenance applications.

The TRT Advanced Series builds upon those capabilities with higher output voltage, modern touch-screen operation, automatic testing workflows, reusable templates, and specialized CVT testing capability.

For organizations testing transformers every day, the additional automation and productivity offered by the TRT Advanced Series can significantly reduce testing time while improving consistency and reporting quality.

As an authorized DV Power distributor, RCC Electronics can help you determine which TRT model best fits your transformer testing requirements.

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