Causes of vibration faults in high-pressure fans and debugging steps

Maintenance of high-pressure fans

1. Check whether the fixing or connecting bolts are loose

2. Check whether the impeller is deformed and whether the belt is aged

3. If the high-pressure blower is stored for a long time or has been out of use for more than one year, the original lubricating grease on the main shaft bearing of the high-pressure blower may be oxidized and form a gel-like film on the bearing. In this case, the bearing must be cleaned and the original lubricating grease replaced with new grease of the same composition.

4. If the high-pressure fan is stored for a long time or is not in use, it is necessary to check whether the motor is damp or submerged in water, etc. Otherwise, it should be dried at the motor manufacturer. The motor bearings should also be cleaned and the grease replaced in accordance with the above requirements.

5. Lubricating oil and grease should be selected as needed. Conventional lubricating oil should be N20-32, and complex lithium-based grease LGHT3 should be used for grease. Special circumstances will be selected separately.

The commissioning steps of high-pressure fans

The fan is allowed to start at full voltage or reduced voltage. However, it should be noted that the current during full voltage starting is approximately 5 to 7 times the rated current. The torque during reduced voltage starting is proportional to the square of the current. When the grid capacity is insufficient, reduced voltage starting should be adopted. When the power exceeds 11KW, it is advisable to adopt reduced-voltage starting.

2. When conducting the test run of the fan, carefully read the product manual and check whether the wiring method is consistent with the wiring diagram. It is necessary to carefully check whether the working voltage of the power supply to the fan meets the requirements, whether the power supply is missing a phase or in the same phase, and whether the capacity of the electrical components provided meets the requirements.

3. During the test run, there should be no less than two people. One person controls the power supply, and the other observes the operation of the fan. If any abnormal phenomenon is found, the machine should be stopped immediately for inspection. First, check whether the rotation direction is correct; After the fan starts to operate, it is necessary to immediately check whether the operating current is balanced and whether the current exceeds the rated current. If there are no normal phenomena, the machine should be stopped for inspection. After running for five minutes, stop the machine to check if there are any abnormal phenomena with the fan. Confirm that there are no abnormal phenomena before restarting the machine.

4. When conducting a test run of a two-speed fan, start at low speed first and check if the rotation direction is correct. When starting the high-speed operation, it is necessary to wait until the fan has come to a complete stop before starting again to prevent reverse rotation at high speed, which may cause the switch to trip and damage the motor.

When the fan reaches its normal rotational speed, it is necessary to check whether the input current of the fan is normal. The operating current of the fan must not exceed its rated current. If the operating current exceeds its rated current, it is necessary to check whether the voltage supplied to the fan is normal.

6. The motor power required by the fan refers to the greater power needed for the centrifugal fan and fan box under certain working conditions when the air inlet is fully open. If the motor is operated with the air inlet fully open, there is a possibility of motor damage. When the fan is being tested, close the valves on the inlet or outlet pipelines of the fan. After it starts running, gradually open the valves until the required working conditions are reached.

Causes of vibration faults in high-pressure fans:

The fan and the motor are connected by a coupling to transmit motion and torque. Misalignment is a common fault of fans, and 60% of fan faults are related to misalignment. The misalignment fault of a fan refers to the degree of inclination or offset between the centerlines of the two rotors of the fan and the motor and the centerline of the bearing. The misalignment of the fan rotor can be classified into coupling misalignment and bearing misalignment.

After a misalignment fault occurs in the fan rotor system, a series of dynamic effects that are unfavorable to the operation of the equipment will occur during the rotation process, causing the deflection of the coupling, the wear of the bearing, the stable state of the oil film and the deflection deformation of the shaft, etc. This not only changes the mutual position between the rotor journal and the bearing and the working state of the bearing, but also simultaneously reduces the natural frequency of the shaft system. The rotor is subjected to force and the additional force on the bearings causes abnormal vibration of the fan and premature damage to the bearings, which is highly harmful. For the misalignment fault of the fan, a laser alignment instrument can be used to solve it, which is convenient and fast.