How is the transformer winding resistance test performed?

The transformer winding resistance test is typically performed using precision ohmmeters or winding resistance testers. These devices apply a low DC current to the transformer windings and measure the resulting voltage drop across the windings to accurately calculate resistance. Ensure the transformer is de-energized and isolated before testing. Connect the tester leads to the winding terminals and set the appropriate test current, usually between 10A to 100A depending on the transformer size. Monitor the readings, considering the temperature to apply corrections as necessary. This test aids in identifying potential issues like loose connections or winding faults, ensuring compliance with transformer oil testing standards for optimal operation and longevity of the transformer.