Megger FRAX Series Sweep Frequency Response Analysers

The Megger FRAX Series Sweep Frequency Response Analysers are engineered for precision transformer diagnostics in demanding field environments where accuracy, repeatability, and structural insight are essential. Designed around a wide sweep range extending from 0.1 Hz to 25 MHz, the FRAX instruments generate a detailed frequency-response signature that reveals subtle mechanical or electrical changes within transformer windings and cores. With default resolutions of over 1,000 data points per sweep and optional ultra-high resolution modes reaching 32,000 points, the system delivers exceptionally fine diagnostic granularity while maintaining rapid test times of approximately 64 seconds in standard mode, or as low as 37 seconds in fast-sweep operation. The measurement architecture offers a deep dynamic range, exceeding 120 dB on the FRAX 099 and extending beyond 140 dB on the FRAX 101 and FRAX 150, allowing the analyser to detect minute variations that would otherwise be lost in electrical noise.

Engineered for field deployment, the FRAX series combines robust mechanical construction with carefully controlled grounding and cabling systems to ensure highly repeatable results even under inconsistent site conditions. Instruments weigh as little as 1.8kg, and operate reliably between -20°C and +50°C, making them suitable for substation testing, post-transport inspections, and on-site condition assessments. The portable FRAX 099 connects via USB to a laptop for control and data analysis, while the FRAX 101 adds Bluetooth connectivity and built-in ground loop detection to verify measurement integrity before testing. The FRAX 150 integrated a full PC and high-visibility colour screen into a mains-powered, field-ready enclosure, enabling completely standalone operation without external hardware.

Across all configurations, the FRAX series delivers a powerful diagnostic platform capable of identifying axial or radial winding displacement, core movement, shorted or open windings, degraded clamping structures, and other mechanical changes that traditional electrical tests often fail to detect. By comparing frequency-response signatures against commissioning fingerprints or historical records, operators can track long-term condition trends or verify structural integrity after short-circuit events, transportation, or mechanical stress. With its wideband measurement capability, fast operation, and compliance with IEC and IEEE SFRA standards, the FRAX series provides an advanced, data-driven solution for ensuring transformer reliability, supporting asset lifecycle decisions, and reducing the risk of unexpected failure in high-value power network infrastructure.

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Megger part number: FRAX

The Megger FRAX Series is available as three different models, which are as follows:

• FRAX 99
• FRAX 101
• FRAX 150

View the table below to compare these options and see which is the most suitable for you.