Question

With the aid of a suitable diagram, describe the procedures when conducting polarity test on a tranformer.

Answer 1

Polarity test is conducted on transformer to know the polarity for parallel operation of transformer. If correct polarity is not known there is a chance of damage to the winding of the transformer

Procedures:

1).Connect any two terminals of a transformer

2). Connect another two terminal with voltmeter of MI type.

3) Connect the transformer with the rated supply.

4.) Observe the voltmeter reading connceted across two terminal.

5.) If voltmeter shows additive voltage change the terminal and if it shows subtractive voltage it is connected with correct polarity.

Subtractive voltage is preferable because it applies less stress on the windings as compared to the additive voltage.