how to do megger test of transformer?

To perform a megger test on a transformer, first ensure the transformer is de-energized and disconnected from the power supply. Connect the megohmmeter leads to the transformer windings and ground. Set the megger to the appropriate voltage (typically 500V or 1000V) and initiate the test. Record the insulation resistance readings, which should be above the manufacturer’s specified minimum. Repeat the test for each winding and between windings to assess insulation integrity.