Repair methods for the failure of fan speed regulation function

The repair methods for the failure of fan speed regulation function can take targeted measures according to the cause of the fault. The following are the specific analysis and handling steps:

First, troubleshooting

Confirm the status of the speed control switch

Check the contact of the contacts: Use a multimeter to test the on-off characteristics of each position of the speed control switch. If there is poor contact or short circuit in the position, the contacts need to be ground or the switch replaced.

Observe the mechanical structure: Check if the knobs are stuck, if the keys are stuck or unable to spring up. Clean the contacts or replace the microswitches if necessary.

Inspect the motor and windings

Measure the coil resistance: Use a multimeter to measure the resistance values of the motor's speed regulation winding and secondary winding. If there is any false soldering, desoldering or short circuit, the motor needs to be re-soldered or replaced.

Check the starting winding: Confirm whether the starting winding is open-circuited. Repair or replace the motor if necessary.

Verify the capacitors and inductors

Capacitor capacity testing: Measure the capacitance of the capacitor with a multimeter. If it is lower than 70% of the nominal value, a capacitor of the same specification needs to be replaced.

Inductor winding inspection: Check if the inductor winding is short-circuited. If it is short-circuited, it needs to be rewound or replaced.

Check the wiring connection

Confirm the correct wiring: Check whether the circuit connection between the speed controller and the motor is correct, and ensure there is no wrong connection or open circuit.

Check for false solder joints: Inspect the solder joints on the circuit board. If there are any false solder joints or desolvation, use an electric soldering iron to reinforce them.

Second, maintenance and handling

Replace the damaged parts

Speed control switch: If the speed control switch is damaged, a switch of the same specification needs to be replaced.

Capacitors or inductors: If the capacitors or inductors are faulty, components of the same model need to be replaced.

Motor: If the internal windings of the motor are short-circuited or open-circuited, a motor of the same specification needs to be replaced.

Cleaning and Lubrication

Clean the contacts: Use a precision electrical cleaner to clean the contacts of the speed control switch, circuit board contacts, etc., to remove oxides and accumulated dust.

Lubricate the rotating shaft: Spray a small amount of lubricating oil into the gaps of the rotating shaft to reduce rotational resistance.

Re-welding and reinforcement

Soldering loose solder joints: Use an electric soldering iron to reinforce the loose solder joints on the circuit board to ensure a firm connection.

Repair the open circuit point: If there is an open circuit in the line, the open circuit point needs to be located and re-welded.

Adjustment and Testing

Adjust the governor: If the internal contacts of the governor are adhered or the potentiometer is damaged, the adhered contacts need to be repaired or the potentiometer replaced.

Test the speed regulation function: After the maintenance is completed, power on and test the speed regulation function of the fan to ensure that the rotational speeds at all gears are normal.