標準號：BS EN 62021-2-2007
中文標準名稱：絕緣液體.酸度的測定.比色滴定法
英文標準名稱：Insulating liquids - Determination of acidity - Colourimetric titration
標準類型：E38
發布日期：2007/8/31 12:00:00
實施日期：2007/8/31 12:00:00
中國標準分類號：E38
國際標準分類號：29.040.10
引用標準：IEC 60475;IEC 60567;ISO 5725;ISO 6619
適用范圍：This part of IEC 62021 describes a procedure for determination of the acidity of unused andused electrical mineral insulating oils.NOTE 1 In unused and used mineral insulating oils, the constituents that may be considered to have acidiccharacteristics include organic acids, phenolic compounds, some oxidation products, resins, organometallic saltsand additives.The method may be used to indicate relative changes that occur in a mineral insulating oilduring use under oxidizing conditions that may or may not be shown by other properties of theresulting mineral oil.The acidity can be used in the quality control of unused mineral oil.As a variety of oxidation products present in used mineral oil contribute to acidity and theseproducts vary widely in their corrosion properties, the test cannot be used to predictcorrosiveness of a mineral oil under service conditions.NOTE 2 The acidity results obtained by this test method may or may not be numerically the same as thoseobtained by potentiometric methods, but they are generally of the same magnitude. The potentiometric methoduses an endpoint at pH 11,3 to ensure titration of all species, whereas the colourimetric methods uses an indicatorchanging colour at approximately pH 9,5. This may lead to slightly higher results for oils with acidities above0,3 mg KOH/g oil when using the potentiometric method.