Transformer & Winding Test Equipment

Advanced diagnostic instruments for winding resistance, turns ratio, tap changer analysis, demagnetization, and frequency response testing.

Power transformers are among the most critical and costly assets in any electrical system. Detecting problems early — before a failure — requires the right instruments and the right application knowledge. ProgUSA supplies DV Power transformer test equipment to utilities, electrical service providers, and industrial facilities across the United States, backed by application support, training, calibration, and repair.

Request Demo          Talk to ProgUSA   

What transformer and winding test equipment covers

• Winding resistance measurement (IEC 60076-1)
• Turns ratio measurement of power and instrument transformers
• On-load tap changer (OLTC) analysis and dynamic resistance measurement (IEC 60214-1)
• Transformer demagnetization and demagnetization status verification
• Sweep frequency response analysis (SFRA)
• Excitation current measurement
• Phase angle measurement
• Transformer vector group detection
• Heat run testing (IEC 60076-2)
• Magnetic balance testing

Featured DV Power transformer test instruments

The battery-operated TWR250B is the latest DV Power solution for a three-phase transformer, designed to measure winding resistance and turns ratio. TWR250B is capable of testing six transformer windings with a single cable connection, as well as three-phase automatic transformer demagnetization. It has an automated test mode, where the instrument operates the tap changer without operator input (minimizing the risk of human error) and records winding resistance and turns ratio results based on pre-selected criteria.

Together with the turns ratio, the instrument also measures excitation current and phase shift. This enables the detection of transformer core or winding-turn failures that cannot be detected by measuring the turns ratio alone. It has a built-in true three-phase power source. For that reason, they can test transformers with special configurations, such as phase-shifting, rectifiers, arc-furnace, traction transformers, etc.

The instrument can output test current up to 25 A DC for winding resistance tests and voltage up to 250 V AC for turns ratio test, but it can also output a very low test voltage of 1 V AC, which is necessary for turns ratio verification of the majority of current transformers. TRT250B is equipped with a large 10.1” graphical touch-screen display. The most important are the test templates and the automatic test mode. Users can simply create test templates, store them in the instrument’s memory, and load them when in the field with just a few clicks.

Sweep frequency response analysis (SFRA) is a method to evaluate the mechanical integrity of core, windings, and clamping structures within power transformers by measuring their electrical transfer functions over a wide frequency range.

FRA500 injects a sine wave signal with constant amplitude and variable frequency (user-selectable voltage from 0,2 Vpp to 24 Vpp and frequency from 0,1 Hz to 25 MHz) to one side of a transformer winding. These amplitudes and phase angle values of the reference (output) signal are then compared with the corresponding values of the measured signal (from the second side of the winding). The ratio of the measured signal and reference signal magnitude is graphically displayed in dB through the full sweep frequency.

Discover more