1. Short-circuit the transformer's "input" and "output" terminals and test their insulation resistance to ground using a megohmmeter. When measuring with a 1000V megohmmeter, the resistance should be greater than 2M ohms.
2. The cross-sectional area of the transformer's input and output power lines should meet the requirements of their current values; a current density of 2-2.5A/min² is recommended.
3. The three-phase input and output power lines should be connected to phases A, B, and C respectively, according to the yellow, green, and red busbar colors on the transformer terminal block. The neutral wire should be connected to the transformer's neutral wire. The grounding wire, transformer casing, and transformer center point should be connected. The grounding wire and neutral wire are usually drawn from the transformer's neutral point. (If the transformer has a casing, the connection should correspond to the grounding markings on the casing).
Check the input and output lines to ensure they are correct.
4. First, power on under no-load and observe whether the input and output voltages meet the requirements. Simultaneously observe the machine for any abnormal noises, sparking, or unusual odors. If any abnormalities are found, immediately disconnect the input power.
5. Only after the no-load test is completed and runs normally can a load be connected.
