what is no load test of transformer?

The no-load test of a transformer is conducted to determine its core losses, which include hysteresis and eddy current losses, when the transformer is energized without any load connected. During this test, the primary winding is connected to the rated voltage while the secondary winding is left open. The input current, voltage, and power are measured to calculate the transformer’s efficiency and performance characteristics under no-load conditions. This test helps assess the transformer’s design and operational efficiency.