Purpose of no-load test:

(1) When no-load current and no-load loss are taken into account, parameters such as excitation impedance of transformer can be calculated, and the conversion ratio can be calculated.

(2) Local and overall defects in transformer magnetic circuit can be found, such as poor insulation between silicon steel sheets, insulation damage of piercing screw or pressure plate, etc.

(3) Some problems of transformer coil can be found, such as inter-turn short circuit of coil, short circuit of parallel branch of coil, etc.

The purpose of short circuit test is:

(1) Measure the voltage, current and loss of the transformer during short-circuit, and calculate the copper loss and short-circuit impedance of the transformer.

(2) Check the correctness of coil structure.