How to do the maintenance of negative pressure fan? You can refer to the following three points. 

1, motor repair and maintenance: first of all, we must turn off the main power supply and check that the connection between the motor and the ground is good. Then tighten the screws and couplings. Check the insulation resistance of the motor to meet the requirements and check the contact of the main circuit. If the contact (severe erosion of the contact point wears off 1 / 3 of the original thickness), replace the contact. 

2, air valve: the test for the air valve can be divided into the following four steps: 1, adjust the belt loosening and tightening, and the wind wheel turns the handwheel to observe whether it is smooth or not. 2. Check and replace the joints and sealing packing between the pads. 3. Clean the car and wind wheel and shell, filter. The paint that should be painted comes off. 4. The rotating part is filled with lubricating oil, in order to ensure the coupling and the flexibility and stability of the bearing. 

3, circuit maintenance and maintenance: it is divided into five points. 1. The mechanical opening and closing action of the check valve is reliable, flexible, and the opening and closing angle is clear. 2. It is normal to check the lamp voltage and ammeter manually. There is no sound in part of the operation of each wind turbine, and the current three-phase balance. 3. It is normal to check the control points of the control box assembly. 4. Power on for three times and check that the remote control is correct and reliable. 5. The test runs for two hours to observe the temperature rise of the motor bearing and whether the temperature is moving normally.