What information is obtained from open-circuit and short-circuit tests on transformers?

Open-circuit test (apply rated voltage to one winding, other open): measures core losses and magnetizing impedance. Input power equals core loss (hysteresis + eddy current). No-load current is small (2-5% of rated). Short-circuit test (apply reduced voltage to one winding, other shorted): measures copper losses and leakage impedance. Full-load current flows at 5-10% rated voltage. These tests determine equivalent circuit parameters for efficiency calculation and regulation prediction.