TESTING OF TRANSFORMER

Transformer tests:

There are 5 main tests of a Transformer

1.Polarity Test:This test is used to determine the polarity of primary and secondary.This test is carried out but connecting a voltmeter across the primary and secondary and if the voltmeter reads the sum of primary and secondary voltages then the secondary terminal is of opposite polarity with respect to primary.It the voltmeter reads the difference of the primary and secondary voltages then the secondary terminal is of the same polarity with respect to primary.

2.Dc Kick Test:This test is also used to find the polarity but here we connect ammeter across the secondary.

3.Open Circuit Test:This test is generally done on the Low voltage side of a Transformer and it is used to find the

• Constant losses /Iron losses
• The shunt parameters
• Hysteresis and Eddy current losses

4.Short circuit test:This test is generally done on the High voltage side of a Transformer and it is used to find the

• Variable losses/Cu losses
• Series parameters

5.Sumpner's Test:In open circuit and short circuit test it is not possible to find Iron and Cu losses together at a time so the exact temperature rise of Transformer cant be detected so Sumpner's test is used to find both Iron and Cu losses at a time.Sumpner's test is also known as BACK TO BACK TEST.