Dissolved Gas Analysis (DGA) Instruments

The Doble Delphi Instruments are dissolved gas analysis analyzers and monitors that help you check and track transformer health by providing early warning signs of problems such as overheating, insulation degradation or mechanical movement within the unit.

The Doble Delphi on-line monitoring devices provide valuable information in real time, second by second. The Delphi Portable is used for in-field dissolved gas analysis when you need to take a closer look at the data.

The Doble Delphi is available in Standard, Mini and Portable models. The monitors attach directly to a transformer valve or can be mounted adjacent to the transformer when the need arises.

The portable device puts more detailed DGA readings at your fingertips during routine testing or emergency situations.

Learn more about the Delphi Portable.


Features and Benefits of the Dephi on-line monitors


  • Patented* vacuum resistant membrane prevents failure during oil surges, maintenance or other activities
    * patents include US and Canada

  • Fast response time: getting to 80% of step change in less than 7 minutes means that indications of a problem are given that much sooner and effectively

  • Gas selectivity is high – meaning appropriate measurements rapidly, whether single gas or combined gas

  • Micro pump option – allowing for oil circulation to ensure oil doesn’t go stale and give misleading results (Available in Standard Delphi)

  • Single valve application ensures minimal connection to the transformer

  • Robust, field ready device comes complete with self-test and diagnostics automatically performed on the sensor itself

  • Only requires one transformer valve for operation


  • Single value output

  • High accuracy and repeatability

  • Micro-pump circulation (Available in the Standard Delphi)

  • Vacuum withstand

  • Moisture Detection (Available in the Standard Delphi)

  • Temperature & Sensor Condition Self Diagnostics

  • Continuous Level and trend analysis

  • On-line alarms and indicators

  • Front-panel configuration and PC based Software

  • Communication Options

Interested in learning more?

     The Doble Delphi: Frequently Asked Questions

     Application Notes:


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