how to check polarity of single phase transformer?

To check the polarity of a single-phase transformer, you can use the “dot convention” method. First, identify the primary and secondary windings. Connect a low-voltage AC source to the primary winding. Then, use a voltmeter to measure the voltage across the secondary winding. If the voltmeter shows a positive reading when the primary is energized, the polarities are correct. If the reading is negative, the connections are reversed, indicating incorrect polarity.