The GlobeCore TOR-1 can detect both dissolved and free water in transformer oil, helping prevent dielectric breakdown and prolong transformer life.

One important aspect when selecting a dissolved water tester for transformer oil is measurement stability under field conditions. At many power substations, temperature fluctuations and oil contamination can affect the accuracy of conventional moisture testing methods. Portable devices with fast response times and automatic calibration features are usually preferred for maintenance teams working directly on energized equipment. Modern compact analyzers, such as the TOR-1, are often used, because they allow engineers to quickly assess moisture conditions on site before insulation problems become critical. The photo below shows an example of this type of portable transformer oil moisture tester.

You’re right to prioritise measurement stability in the field. The TOR-1 portable oil moisture tester is designed for that use: it uses a capacitance sensor that gives long-term stability and good resistance to contamination, provides rapid on-site readings of dissolved water (0–500 ppm and 0–1 aw) and oil temperature, and is built for substation fieldwork with a rugged enclosure, stabilized power input and fast response suitable for maintenance teams working near energized equipment. It also has useful on-board outputs (configurable analog outputs, built-in printer) so you can record results immediately without a PC.

Keep in mind it’s a rapid screening tool rather than a full laboratory analyzer: results are excellent for immediate decision-making and trend monitoring but should be confirmed by a certified lab when you need definitive moisture certification. The unit is specified for insulating mineral oils up to ~70 cSt at 50 °C and operates in the 0–55 °C range, so check oil type and ambient conditions before relying on single-point readings. If you also need dissolved hydrogen or a broader diagnostic suite and easier calibration/no consumables, consider the next-step analyzers (e.g., TOR-2) and follow a practice of periodic lab cross-checks or reference-sample checks to maintain field-test confidence.