Total acid number tests

Testing of transformer oil, electrical oil is normally subject to some structure.
For example in the UK testing methods are stipulated and a British standard exists for tests to be conducted and includes some rejection limits (BS 5730) .Similar standards exist in Europe.
Classic methods are employed and currently little or no use for FTIR.

TRANS,

TAN is measuring the weak organic acid concentration by titrating against a known concentration of standard alkali (caustic)such as KOH - it's normally a weak caboxlyic acid that is in the oil. pH measures the acidity which is different to TAN measuring the concentration of the weak acid species and what you are doing is monitoring the increase in these acidic by products. It's due to the acidic by products laying sludge and varnish which can block oil ways and reduce the cooling effect of the oil. It can also damage celluose material. The oxidation by products can also conduct electrical charge so reducing the insulating properties of the transformer oil.

I have come across both ASTM D664 and D974 to measure TAN. I am not familiar with any quick test kits. Given when a transformer goes, the downtime can be lengthy with expensive repairs, transformer oil condition monitoring is vital.

The FTIR does not measure the TAN, it uses a complex mathematical model (algorithms) to predict the TAN. From my understanding, there are only recent movements towards using FTIR to predict the TAN - so not many labs are doing it as it's labour intensive in setting up the models. It's very important to ensure that the correct chemical models are used to predict the TAN.

Most commercial labs do offer a range of test suites to test transformer oil. You best solution will be to use a reputable lab preferably one that routinely does transformer oil analysis.

I have used both of Dexsil Corp's test kits (TBN and TAN)over the years and alway's had great success with them. By the time you get to the final reading the original opaqueness of the oil is gone, having been filtered out earlier in the test process. Quoted from the TAN test kit description "Oil color will not interfere with the test because the colorimetric end point is carried out in the aqueous phase."

As stated above the best solution is to use a reputable lab. However for expedient field test the Dexsil test kit's can't be beat.

Information about Dexsil Corp. can be found right here on Noria's website. http://www.noria.com/buyersguide/dexsil.asp Here's a link to Dexsil Corp's site with links for both the TBN and TAN test kits as well as their HydroScout moisture test kit. http://www.dexsil.com/products/detail.php?family_id=4&a...t.y=10&submit=Search