Moisture in oil analyzer

Data records

• An online moisture transmitter uses a thin-film polymer capacitive sensor that is selective to water and whose capacitance changes as the film takes up water from the oil; it reads relative saturation, the share of the water the oil can hold at its temperature. Source: Vaisala application page, web page edition. Verified 2026-10-27. Record instr.moisture-in-oil-analyzer.capacitive-sensor
• A moisture-in-oil analyzer determines the water content of an insulating liquid, either as an absolute concentration by titration of a drawn sample in the laboratory or as a relative saturation sensed continuously by a probe in the oil. Source: Vaisala application page, web page edition. Verified 2026-10-27. Record instr.moisture-in-oil-analyzer.definition
• Water is brought into the titration cell either by direct injection of the oil sample or by the oven technique, in which the heated sample releases its water as vapor that an inert carrier gas such as nitrogen carries into the cell, since the oxygen in air could react with the sample. Source: Mettler Toledo application note page, web page edition. Verified 2026-10-27. Record instr.moisture-in-oil-analyzer.direct-vs-oven
• In coulometric Karl Fischer titration the iodine that reacts with the water is generated electrochemically in the titration cell and the water content follows from the electric charge consumed; it is the Karl Fischer variant that resolves the low water contents found in insulating oil. Source: Metrohm application bulletin page, web page edition. Verified 2026-10-27. Record instr.moisture-in-oil-analyzer.karl-fischer-coulometric
• An online transmitter is installed through a ball valve, which can be done on an energized transformer, and its continuous readings mean that no sample has to be drawn for a laboratory moisture determination; the sensor recovers on its own after full saturation. Source: Vaisala application page, web page edition. Verified 2026-10-27. Record instr.moisture-in-oil-analyzer.online-installation
• With the oven technique the sample never contacts the titration cell, and a temperature scan of each oil type is run first to find the extraction temperature at which its water is released. Source: Mettler Toledo application note page, web page edition. Verified 2026-10-27. Record instr.moisture-in-oil-analyzer.oven-temperature-scan
• Water in the oil degrades the dielectric properties of the insulation and raises the aging rate of the insulating materials, and in extreme cases a transformer fails from excessive water in its oil, which is why a low water content is treated as a condition of safe and reliable operation. Source: Mettler Toledo application note page, web page edition. Verified 2026-10-27. Record instr.moisture-in-oil-analyzer.paper-insulation
• Relative saturation is read directly and is insensitive to additives and contaminants in the oil, while an absolute value in parts per million is also output for transformer oil; relative saturation is the quantity that relates to the dielectric strength of the oil. Source: Vaisala application page, web page edition. Verified 2026-10-27. Record instr.moisture-in-oil-analyzer.relative-saturation-vs-ppm