During the application process, any equipment may encounter failure issues. Cabinet centrifugal fans may experience problems like a decrease in speed. In this case, it’s important to use the correct troubleshooting methods to effectively address the issue.

Most of our users are familiar with the application knowledge of cabinet centrifugal fans, which are essentially variable flow constant pressure devices. Recently, some users have reported that the fan speed becomes unstable during operation.

Reason 1: Check if only one of the rectifier diodes has an issue.

Reason 2: The adjustable resistor. Since the adjustable resistor in cabinet centrifugal fans is installed on the control panel, it’s used frequently. Over time, poor contact is common.

Reason 3: The silicon-controlled rectifier (SCR). These are often problematic, typically due to short circuits, open circuits, lack of triggering, or poor internal contact.

Reason 4: Another important reason is to check if there is carbon powder or carbon brushes between the motor rotor and the rectifier. Following the maintenance principle of “easy to difficult,” first, measure the adjustable resistor and ensure its resistance value changes appropriately when adjusted, confirming the potentiometer is functioning properly. Then measure the SCRs, and if no issues are found, check the diodes. Since diodes are high-current metal-sealed tubes, one side of the screw is fixed to the circuit board, while the other side is soldered to the circuit board. If the positive and negative terminals are loose, and when measuring, if you notice any shaking, then confirm the diodes’ status.

Cabinet centrifugal fans feature a compact design, low vibration, light weight, and easy installation and maintenance. They are widely used in places requiring fire smoke exhaust, kitchen grease removal, and ventilation (such as in hotels, restaurants, theaters, basements, factories, mines, office buildings, etc.). If abnormal noises, excessive motor heating, charged casing, tripped switches, or failure to start occur during operation, the fan should be immediately stopped and inspected.