What are the common faults and repair methods of axial flow fans?

The fan does not rotate:
Reason: The power may not be connected; the transmission line connector is loose, the oxidation contact is poor; the fuse is blown; there is a short circuit or open circuit in the axial flow fan, transmission line, rectifier circuit, etc.
Repair method: Check and connect the power; remove the oxide and connect the transmission line connector firmly; replace the blown fuse with the same specification fuse; the open circuit fault can be measured by measuring the output voltage of the axial flow fan output end, finding the internal broken wire, the rectifier diode broken wire or the generator coil broken circuit and other broken circuit points, and replacing the damaged components; the short circuit fault can be treated by using a three-phase bridge rectifier circuit, and using a multimeter to measure the forward and reverse resistance values ​​of the six rectifier diodes of the rectifier. If the forward and reverse resistance of each diode is very small, it may be that the diode or the fan is short-circuited, and they should be repaired or replaced separately.
The fan rotates slowly:
Reason: The speed has not reached the normal speed. It may be that the lubricating oil of the cooling fan evaporates, resulting in insufficient fan power; it may also be that the fan is over-accumulated with dust, affecting the power supply heat dissipation, resulting in unstable operation.
Maintenance method: properly adjust the blades of the cooling fan so that its speed meets the power requirements of the radiator; try to apply external force to rotate the fan. If there is a sign of micro-motion or large resistance during rotation, it means that the lubricating oil has evaporated. The fan frame blades can be removed, and some oil can be added to the fan shaft. Turn it several times by hand and reinstall it after feeling no resistance; regularly maintain the cooling fan and clean the dust.
Increased noise:
Cause: The fastener nut fixing the fan frame may be loose; the rolling bearing of the fan equipment lacks oil, resulting in dry friction; the rolling bearing is damaged and loose; the impeller collides with other parts.
Maintenance method: tighten the nut and add a self-locking nut between the screws to prevent the frame from loosening again; open the front and rear bearing covers, remove the bearings for inspection, if there is a lack of oil or the lubricating grease is dry, the bearings should be cleaned and the appropriate lubricating grease should be adjusted; replace the damaged rolling bearings; check whether the impeller and other parts have collisions or friction. If the installation is poor, it should be repaired, reassembled and adjusted.
Excessive vibration:
Reason: The shaft and the motor shaft are not concentric or skewed; the impeller blades are corroded, worn or have attachments, causing the impeller to be unbalanced, and dynamic balancing correction is not performed after replacing the impeller blades; the coupling is installed misaligned or has gaps; the foundation is not rigid enough or is not firm; the anchor bolts, the housing and the bracket or the bearing base bolts are loose; the fastening bolts between the impeller hub and the shaft disc or the streamline cover and the base disc are loose; the bearing is poorly installed or damaged; the inlet and outlet pipes are poorly installed.
Maintenance method: make adjustments and re-align; carefully check and replace the impeller blades, re-correct the dynamic balance; re-adjust the coupling; strengthen the foundation; tighten all bolts; carefully check and tighten the bolts; inspect and replace the bearings; inspect the inlet and outlet pipes.
Bearing failure (such as damage, deformation, displacement, etc.):
Reason: improper use and poor lubrication.
Maintenance method: Reasonably select axial flow fan lubricating oil and lubricate the bearings in time to reduce the friction of the bearings and operate safely.
Heating:
Reason: When the wind pressure enters the fan, the system resistance is too large, the pipe network resistance coefficient is too large, the pipe network valve is not fully opened, the motor is overloaded, etc., causing the motor to overheat.
Maintenance method: The motor should operate within the specified parameter range to ensure that the hardware conditions connected to the axial flow fan meet the use requirements (including voltage and current), and regularly adjust the resistance network of the air duct to reduce the resistance value.
Excessive motor current and high temperature rise:
Reason: The inlet and outlet pipes are not closed tightly when the machine starts; the input voltage is low or the single-phase power supply; the spindle speed exceeds the rated value; the input medium density is too high or the temperature is too low; the motor bearing is damaged; the bearing is short of oil or too much oil is added; system changes cause the fan load and motor load to increase.
Maintenance method: Close the inlet and outlet pipes; check the power supply; adjust the spindle speed; check the medium density and temperature; inspect the motor bearings; adjust the oil volume of the bearings; check the system and make corresponding adjustments.
When repairing the axial flow fan, be sure to cut off the power supply first to ensure safety. If you are not sure about the cause of the fan failure or do not have the relevant maintenance skills, it is recommended to seek help from professionals. In addition, regular cleaning and maintenance can effectively reduce the occurrence of failures.
If you want to know the common failures and repair methods of axial fans, you can contact our professional technicians, and we will wholeheartedly provide you with the best service!