What are the common faults of negative pressure fans?

Negative pressure fans are primarily used for ventilation and cooling. Common faults include motor problems, abnormal blades, and excessive vibration.

The following are the main fault symptoms, causes, and solutions:

1. The fan does not start or operates normally
Possible causes:
Power is disconnected or voltage is unstable.
Motor burnout or capacitor damage.
Control circuit failure (such as a damaged relay or contactor).
Solution:
Check the power supply, fuse, and switch for proper operation.
Measure the motor windings for open circuits or short circuits, and replace any damaged motors or capacitors.
Check the control circuit and repair or replace any damaged electrical components.

2. The fan operates but airflow is low
Possible causes:
Dust accumulation or deformation on the blades.
Loose belt (belt drive models).
Blocked air inlet or outlet.
Slowed motor speed (undervoltage or bearing wear).
Solution:
Clean dust from the blades or replace deformed blades.
Adjust the belt tension or replace the belt.
Clear any obstructions at the air inlet and outlet.
Check the voltage for stability and replace worn bearings.

3. The fan is noisy or vibrating violently
Possible causes:
Unbalanced or deformed blades
Worn or insufficiently lubricated bearings
Loose fixing screws
Unstable or uneven fan base
Solution:
Realign or replace blades
Replace bearings and lubricate
Tighten all screws
Reinforce the fan base to ensure stable installation.

4. Motor overheating or frequent tripping
Possible causes:
Motor overload (e.g., excessive blade resistance)
Overhigh or low voltage
Poor motor heat dissipation (e.g., dust blockage)
Waist short or leakage
Solution:
Check for blade deformation or excessive resistance
Ensure stable voltage to avoid overvoltage or undervoltage operation
Clean motor cooling vents and improve ventilation
Check wiring to eliminate short circuits or leakage.

5. Belt wear or breakage (belt drive)
Possible causes:
Aging or poor quality belt
Pulley misalignment
Belt too loose or too tight
Solution:
Replace a new belt (use an appropriate model)
Adjust the pulley to ensure alignment
Adjust the belt tension (it should feel firm when pressed by a finger)

6. Fan leaking or poor sealing. Possible causes
Deteriorated or damaged sealant strips
Deformed fan housing or loose screws
Loosely closed louvers (if any)
Solution:
Replace sealant strips
Repair deformed housing and tighten screws
Check louvers for sticking, clean, or adjust.

Negative pressure fan common faults and quick treatment table