Transformer Diagnostics

Power transformers are subject to many kinds of physical damage that can be nearly impossible to detect – until the transformer fails. System faults, short circuits, aging or even handling during transportation can compromise a transformer's mechanical structure. Because these problems are difficult to detect, they usually go unnoticed and worsen over time, leading to loss of performance and possibly failure.

Until recently, your options for dealing with these critical problems were limited. You could ignore them and hope for the best. Or, if you suspected damage, you could detank the transformer to make a costly and time consuming visual inspection. Even that might not reveal the damage.

Doble has built on our experience with transformers to create the M4000 Insulation Analyzer series and M5000 Sweep Frequency Response Analyzer (SFRA) series.


The M7100 Power Apparatus Analyzer is revolutionizing testing by making it safer, faster and more efficient. Designed to dramatically cut testing time, the M7100 also limits safety risks by reducing ladder and bucket trips, while incorporating a truck full of test sets into one piece of equipment.


M4100 4th Gen 

The M4100 is the world’s premier power apparatus and insulation test instrument. Its unique combination of test capabilities and artificial intelligence analysis software makes it the power industry’s most trusted Power Factor/Tan-Delta instrument. These instruments are used around the globe thanks to their comprehensive testing options, safety features and measurement accuracy.



Doble’s M5300 and M5400 Sweep Frequency Response Analyzers (SFRA) detect mechanical failure or movement of windings due to short circuits, mechanical stresses or transportation. Use them to ensure transformer performance, reduce maintenance cost, and increase service life.

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