how to test a transformer coil?

To test a transformer coil, first ensure the transformer is disconnected from power. Use a multimeter to measure the resistance of the primary and secondary windings; compare these values to the manufacturer’s specifications. Next, perform an insulation resistance test using a megohmmeter to check for insulation breakdown. Additionally, you can apply a low voltage to the primary winding and measure the output on the secondary to verify proper operation. Always follow safety protocols during testing.