
Intrinsically Safe Humidity and Temperature Transmitter Series HMT370EX
For use up to zone 0 and 20
Technical note
Vaisala power transformer monitoring experts, Senja Leivo and Steven Jiroutek answered the most pressing questions from the audience related to moisture in transformer oil in our Q&A webinar.
We invite you to follow the whole webinar, which is available on-demand, and here are just a few examples of the types of questions that were asked:
Q: How can we monitor real time moisture transport between the cellulose paper, pressboard, wood support structures during transformer overload?
A: Online moisture monitoring in the oil circulation gives good indication on how much water is released from paper and other cellulose material surfaces. Moisture from inner parts of paper, pressboard or wood will not move to oil.
Read more of Vaisala online monitors: Optimus™ DGA Monitor OPT100 and Moisture, Hydrogen and Temperature Transmitter MHT410.
Q: Is there any consistent correlation between the top oil temperature and moisture content of the oil? Migration of moisture between paper and oil relative to temperature?
A: The higher the temperature the more moisture migrates out of paper surfaces. However, the amount of moisture coming to oil depends on the moisture content of solid insulation. Characteristics of a specific transformer can be seen with longer time online moisture monitoring.
Q: What is a competitive advantage of Vaisala moisture sensors?
A: Good sensitivity in very dry oil and extremely good long-term stability. Also against degradation from by-products of oil.
Register here to THE webinar to SEE all the questions and answers.

For use up to zone 0 and 20

for transformer oil, hydraulic and lubrication systems in marine and paper industry

for cleanrooms and industrial settings

for refrigerant dryers

for OEM applications

for quick inspections and spot-checking

What relative humidity, dew point, absolute humidity and mixing ratio are, how temperature and pressure distort the reading, and why dew point is…

How humidity behaves in real conditions, the three most common measurement problems, and two practical scenarios —heated air and compressed air—…
When to measure relative humidity vs. dew point, what high and low humidity demand, how temperature and pressure factor in, and when a warmed probe…

Cooling accounts for up to 40% of a data center's energy demand. This Vaisala guide explains how measurement accuracy cuts costs and risks, with a…
A specialist replies with the solution, the instrument and the service that fit.
Instruments to quote
No instruments yet. An enquiry can be sent anyway: a specialist answers.