How Following Crackle Test is Carried for Transformers
Q. Explain how following test is carried for transformers : Crackle test.
Crackle test
The objective of this test is to determine the presence of water or moisture in the oil. In this test a sample of transformer oil under test is taken in a test tube. It is heated on a gas burner, if water moisture is present in the oil, cracking noise is heard. In other method, sample oil taken in the glass beaker of 250 ml. An iron rod of 12.5 mm size is heated to red hot and then plugged into oil under test, if a crackling noise is heard it indicates the presence of moisture in oil.