what is the purpose of open circuit test and short circuit test of a transformer?

The purpose of the open circuit test and short circuit test of a transformer is to determine its core and copper losses, respectively. The open circuit test, conducted with the secondary winding open, measures the no-load losses, primarily hysteresis and eddy current losses in the core. Conversely, the short circuit test, performed with the primary winding shorted, assesses the copper losses due to winding resistance under full-load conditions. Together, these tests help evaluate transformer efficiency and performance.