Sweep Frequency Response Analysers

The FRAX series offers a large dynamic range with high accuracy, and meets all international standards for SFRA measurements

The FRAX150 and FRAX200 sweep frequency response analysers (SFRA) are the smallest and most rugged instruments of their type and powerful tools for revealing potential electrical and mechanical problems in power transformers, many of which are difficult or impossible to detect using other methods.

Meeting all international standards for SFRA measurements, these innovative instruments offer a larger dynamic range and better accuracy than any other comparable test sets currently available. In addition, for the test connections to the transformer, they use a special cabling technology that ensures the repeatability of results.

FRAX200 Datasheet
FRAX Series Datasheet

The FRAX series operates by applying a sweep frequency test signal to the transformer and monitoring its response. The result is a unique fingerprint that reveals a wide range of faults when compared with a reference fingerprint for the same transformer. These include winding deformations and displacements, shorted and open windings, loose and broken clamping structures, core connection problems, core movement, and hoop buckling.

Megger’s FRAX series incorporates powerful analysis and support software. In addition to offering the traditional magnitude versus frequency/phase display, this software allows you to present data in an impedance or admittance versus frequency view, a powerful analytical tool for many transformer types.

The test frequency range covered by the FRAX is 0.1 Hz to 25 MHz, and you can set the range employed for individual tests to match the application’s needs. By default, the number of test points used for each frequency sweep is 1046, but you can extend this up to a maximum of 32 000. The typical measurement time is 64 seconds, but a fast mode is available that can deliver results in just 37 seconds.

Small and easy to carry, with an operating temperature range of -20 ºC to +50 ºC, the FRAX sweep frequency response analysers are ideal for use in the field. They are supplied with ground cable, four 3 m braid sets, two C clamps, 9 m or 18 m connection cables, a user guide, and Windows software.

There are two models in the FRAX series:

• FRAX150: mains-operated with an integrated PC that has a high-resolution colour screen featuring a powerful backlight that makes it easy to read even in direct sunlight and includes a built-in ground loop detector
• FRAX200: a complete and trusted SFRA analyser with repeatable performance test set incorporating automatic testing, demagnetisation and ground loop detection. The FRAX200 delivers high‑resolution SFRA measurements for fast, reliable transformer diagnostics. It ensures repeatability with built‑in demagnetization and automatic ground‑loop checks. Wireless connectivity, USB‑C, and an optional FSX200 switchbox with active clamps streamline field work and enable safe one‑time connection.