One of the smallest and most rugged instruments of its type, Megger’s award winning new FRAX150 sweep frequency response analyzer (SFRA) is a powerful tool for revealing potential electrical and mechanical problems in power transformers, many of which are difficult or impossible to detect using other methods.

The benefits of this novel instrument have recently been recognized in the EEIBA Electrical Industry Awards, where it was named it as Innovative Power Product of the Year for 2009. The judges commented, “Megger’s FRAX150 provides a convenient, reliable and cost-effective transformer monitoring solution. We were impressed with the fact that the product offers analysis and decision support software that facilitates the use of the new test technique of sweep frequency response analysis.”

Megger’s FRAX150 sweep frequency response analyzer is completely self-contained, with an integral PC that has a high-resolution colour screen featuring a powerful backlight that makes it easy to read even in direct sunlight. Meeting all international standards for SFRA measurements, it offers a larger dynamic range and better accuracy than any other comparable test set currently available. In addition, for the test connections to the transformer, it makes use of the internationally standardized cabling technology that ensures repeatability of results.

The FRAX150 operates by applying a sweep frequency test signal to the transformer and monitoring its response. The result is a unique fingerprint which, when compared with a reference fingerprint for the same transformer, reveals a wide range of faults. These include winding deformations and displacements, shorted and open windings, loose and broken clamping structures, core connection problems, core movement etc. winding deformations and displacements, shorted and open windings, loose and broken clamping structures, core connection problems, core movement etc.

In addition to offering the traditional magnitude versus frequency/phase display, the powerful analysis and support software built into the instrument also allows users to present data in an impedance or admittance versus frequency view, which is a powerful analytical tool for many types of transformer.

The test frequency range covered by the FRAX150 is 0.1 Hz to 25 MHz, and users can set the range employed for individual tests to match the needs of the application. By default, the number of test points used for each frequency sweep is 1,046, but users can choose to extend this up to a maximum of 32,000. Typical measurement time is 64 seconds, but a fast mode is available that is capable of delivering results in just 37 seconds.

The Megger FRAX product line contains three products. The top of the line FRAX101 sweep frequency response analyzer, which offers the same performance as the FRAX150 but with some additional functionality and designed for use with an external laptop computer. FRAX101 operates from an internal battery and it supports Bluetooth wireless technology for true wire-free usage. Also available is the economical FRAX99, which is a cost-effective choice for applications where the extensive range of functions provided by the FRAX101 is not needed. All

FRAX models have the same computer software and the measurement data is 100% interchangeable.

Small and easy to carry, with an operating temperature range of -20°C to +50°C, the Megger FRAX sweep frequency response analyzers are ideal for use in the field. They are supplied complete with ground cable, four 3 m braid sets, two C clamps, an 18 m generator cable, an 18m test cable, a comprehensive user manual and Windows software.