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Technical Merits of the Doble M5400 Sweep Frequency Response Analyzer

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Doble_M5400With the Doble M5400 Sweep Frequency Response Analyzer’s non-intrusive test technique, you don’t have to wait for problems to occur, test your power apparatus any time a problem is suspected. Use the Doble M5400 Sweep Frequency Response Analyzer as part of a regular maintenance program, identifying problems before they lead to failure.

Doble M5400 Sweep Frequency Response Analyzer Technical Merits


The M5400 provides a frequency response measurement from 10 Hz to 25 MHz. Doble recommends the default setting of 20 Hz – 2 MHz for transformers as there is limited diagnostic value in measurements outside of this range. The diagnostic frequency range of 20 Hz to 2 MHz covers the most important diagnostic areas:

• Core and Magnetic Properties

• Winding Movement and Deformation

• Interconnections – Leads and Tap Changers 


The M5400 measures the frequency response at logarithmically spaced frequency intervals of 1.2%. A constant excitation level is maintained for each frequency measurement. The M5400 has the ability to auto-scale each frequency measurement providing an overall dynamic range of 80 dB with a ±1 dB accuracy. This gives the highest combination of dynamic range and accuracy available.


The M5400 is a field-ready instrument for high quality measurements. The sweep frequency approach combined with Doble’s world class engineering means that frequency response measurements are highly repeatable and even subtle changes can be used for diagnostic purposes. 

Test Leads

Robust test leads handle the rigors of site testing. International tests have proven repeatedly that the Doble has the most reliable and repeatable test leads available.

Available for rent, lease, or purchase from Protec Equipment Resources.  We are here to help you with your testing equipment needs.

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