The test transformer is a supporting instrument for AC and DC withstand voltage test of electrical equipment of 30KV and below. The test of the test transformer must be performed by professionals, and the test standards and corresponding national standards must be strictly implemented. The ground and console of the test site should be kept dry. Before the withstand voltage test, the test transformer must first check the status of the test product, whether it is still running, and whether it is still live; disconnect the power supply and clean it. When wiring, grounding must be done first. The enclosure of the instrument and operating equipment must have a grounding wire. Before the withstand voltage test, the insulation resistance value of the equipment should be measured to check its insulation.

Before boosting, according to the test voltage requirements of the test product, the voltage must be slowly boosted. After the test voltage is raised within a certain period of time, after the specified test time, the voltage is quickly reduced to zero, and then the power supply is turned off. During the boosting process, if an abnormal situation is found, such as a large pointer swing, scorching or smoking, when the sample makes an abnormal sound, the voltage should be immediately reduced to below 1/3 of the test voltage and the power supply should be cut off to stop the test. You can continue after the reasons are explained. After the test is completed, reset the voltage regulator to zero and cut off the power supply. And do electrical discharge treatment on the sample.

After all the tests are completed, first remove the power supply, then remove the test wire connection, finally remove the grounding wire, clean the test site, and record the test data.