Fault analysis of the fan suddenly stopping during operation

Fault analysis of the fan suddenly stopping during operation

The sudden stop of a fan during operation may be caused by various reasons such as circuit failure, mechanical jamming, overheat protection or external interference. The following is the systematic failure analysis and solutions, classified and explained by priority:

First, electrical system failure

Power supply problem

Reason:

Loose plug/poor contact: The power cord is loosely connected to the socket, causing a momentary power outage.

Power cord open circuit: The internal copper wire breaks (commonly seen at frequently bent areas).

Voltage sag: Voltage drops below the fan startup threshold (such as below 180V) caused by grid fluctuations or the startup of high-power appliances.

Handling:

Check whether the plug is firmly in contact with the socket. Replace the socket if necessary.

Measure the resistance of the power cord with a multimeter (normally it should be less than 1Ω). If it is infinite, the power cord needs to be replaced.

Use a voltage stabilizer or avoid using fans during peak electricity consumption hours.

Capacitor failure

Reason:

Starting capacitor breakdown: An internal short circuit in the capacitor causes the circuit to overload.

Capacity attenuation of the operating capacitor: When the capacity is less than 80% of the nominal value, the motor cannot maintain operation.

Phenomenon:

It makes a "buzzing" sound when starting up and then stops, or suddenly stops rotating during operation without any unpleasant smell.

Handling:

Measure the capacitance value with the capacitance range of a multimeter (for example, if the nominal value is 2μF, the actual measurement should be ≥1.6μF).

Replace the CBB60 type capacitor of the same specification (with a withstand voltage of ≥450V).

The motor winding is short-circuited/open-circuited

Reason:

The insulation layer of the winding is damaged (such as carbonization caused by long-term high temperature).

The wire broke (commonly at the root of the motor lead-out wire).

Phenomenon:

It suddenly stops rotating during operation and is accompanied by a burnt smell, or the fuse blows when restarting.

Handling:

Measure the resistance values among the three leads of the motor with a multimeter (the three-phase resistances should be balanced, with an error of less than 5%).

If the resistance is abnormal (such as infinite or short circuit), the motor needs to be replaced or the coil rewound.

Second, mechanical system failure

The bearing is stuck.

Reason:

The bearing seized up due to the drying up of lubricating oil or the intrusion of dust.

The deformation of the fan blades increases the rotational resistance (such as when hit by foreign objects).

Phenomenon:

Manual rotation of the fan blades is extremely resistant, or the motor makes a "clunk" sound when starting.

Handling:

Disassemble the motor, clean the bearings and add special lubricating oil (such as 3-in-1 engine oil).

Check whether the fan blades are deformed. Correct or replace them if necessary.

The rotating shaft is eccentric or broken

Reason:

Long-term use leads to wear of the rotating shaft, or breakage is caused by external force impact.

Phenomenon:

It stops rotating after severe vibration during operation, or the motor is blocked when restarted.

Handling:

Replace the rotating shaft or the entire motor assembly.

Third, overheat protection is triggered

The motor is overheating.

Reason:

Continuous high-load operation causes the motor temperature to exceed the safety threshold (usually 120℃).

The heat dissipation holes are blocked or the ambient temperature is too high (such as when used in a closed space).

Phenomenon:

It will automatically stop after running for a period of time and can be briefly restarted after cooling down.

Handling:

Clean the dust from the motor's heat dissipation holes to ensure good ventilation.

Avoid prolonged continuous operation or use fans with temperature control protection.

The temperature control switch has failed

Reason:

The contacts of the temperature control switch are stuck or malfunction.

Handling:

Replace the temperature control switch (it needs to match the disconnection temperature of the original fan).

Fourth, external interference and misoperation

Foreign object jamming

Reason:

Light objects (such as cloth strips, paper) are sucked into the fan blades, causing blockage.

Handling:

Cut off the power immediately, disassemble the fan blades and clean up any foreign objects.

Accidental touch of the governor/timer

Reason:

Set the governor to "0" or the timer time is exhausted.

Handling:

Check the gear position of the governor and the Settings of the timer.

Fifth, rapid diagnosis process

Basic inspection:

Observe whether the power indicator light is off → Manually rotate the fan blades (if they are stuck) → Smell if there is a burnt smell.

Step-by-step testing

Replace the power socket → Measure the capacitance → Check the resistance of the motor winding → Clean the bearing and lubricate it.

Verification effect:

After powering on, observe the startup speed (normally it should reach full speed within 3 seconds) → During operation, listen for abnormal sounds (normally it should be uniform wind sound).

Sixth, suggestions for prevention and maintenance

Regular maintenance

Clean the fan blades and heat dissipation holes every quarter and add lubricating oil every year.

Reasonable use:

Avoid prolonged high-load operation. It is recommended to use intermittently (for example, run for 2 hours and then shut down for 15 minutes).

Selection optimization

Choose a fan of appropriate power based on the usage scenario (for example, 30-50W for the bedroom and 60-100W for the living room).

Summary

When a fan suddenly stops, the electrical system (power supply, capacitor, motor) should be checked first, followed by mechanical components (bearings, rotating shaft) and overheat protection. For complex faults (such as short circuits in motor windings), it is recommended to contact professional maintenance personnel. Regular maintenance and reasonable loading during daily use can significantly reduce the failure rate. If the repair cost exceeds 50% of the price of the new fan, it is recommended to replace it directly.