1. New or long unused welding machines often experience a significant decrease in insulation resistance between windings and between windings and the casing due to moisture, which can lead to short circuits and grounding at the beginning of use, causing equipment and personal accidents. Therefore, before use, a shaking table should be used to check whether the insulation resistance is qualified.

2. Before starting a new welding machine, it is necessary to check whether the contactor part of the electrical system is in good condition. If it is considered normal, it can be started for trial operation under no load. Only when there is no electrical hazard can it be tested under load conditions and finally put into normal operation.

3. The DC welding machine should rotate in the specified direction. For those with ventilation fans, attention should be paid to whether the fan rotation direction is correct, and they should be blown out from above. To achieve the purpose of cooling the welding machine.