Solutions To Inverter Overheating Fault

Overheating of the frequency converter is usually caused by factors such as heat dissipation system failure, poor environmental conditions, improper load, or incorrect parameters.

I. Check the Heat Dissipation System

1. Cooling Fan Failure:

Symptoms: Fan does not rotate, rotates slowly, and makes excessive noise.

Solution: Clean the fan of dust or replace it with a fan of the same model. Note that the fan power supply is connected to the internal circuit board of the frequency converter.

 

2. Blocked Airflow:

Symptoms: Heat sinks, airflow ducts, and dust filters are filled with dust, lint, and oil.

Solution: Thorough Cleaning: Use dry compressed air or a soft brush to carefully clean from the inside out. For oil stains, an electrical cleaner can be used.

Cleaning/Replacing Filters: If filters are installed, they must be cleaned or replaced regularly.

 

3. Installation Environment Issues:

Excessive Ambient Temperature: The frequency converter cabinet is installed in direct sunlight, near heat sources, or in a poorly ventilated space.

Solution: Improve the ventilation of the distribution cabinet by adding an exhaust fan or air conditioning. Ensure sufficient ventilation space around the inverter to prevent heat buildup from multiple inverters installed too close together.

Avoid direct sunlight.

 

4. Heat dissipation device issues:

Solution: Retighten the heat sink screws. For cases requiring power module disassembly, it is recommended to have a professional perform the work and reapply high-quality thermal grease.

 

II. Check Load and Operating Status

1. Overload Operation:

Symptom: The motor is overloaded, and the inverter continuously outputs current exceeding the rated value.

Solution: Reduce the load.

Inspect and repair mechanical faults.

If it is a process-related heavy load, consider replacing the inverter or motor with a higher-power one.

 

2. Operating Frequency Too Low:

Symptom: Long-term operation at low frequencies reduces the motor fan's cooling capacity, but the motor still generates significant heat, which is transferred to the inverter.

Solution: Avoid prolonged low-frequency operation.

For applications requiring low-speed operation, switch to vector control mode or install an independent cooling fan for the motor.

 

3. Insufficient Acceleration/Deceleration Time:

Symptom: Frequent starts and stops or rapid acceleration/deceleration lead to excessive instantaneous current and generate significant heat.

Solution: Appropriately extend the acceleration and deceleration times according to load inertia.

 

III. Check Electrical Connections and Hardware

1. Abnormal Input Voltage:

Voltage too high or too low: Both will increase inverter current and heat generation.

Solution: Use a multimeter to measure the three-phase input voltage and ensure it is within the inverter's rated voltage fluctuation range (usually ±10%).

 

2. Output Side Connection Problems:

Poor Contact: Loose screws at inverter output terminals, contactors, and motor junction boxes can cause localized overheating.

Cable Problems: Cables that are too long, too thin, or have damaged insulation.

Solution: Tighten all terminals after power off. Check that the cables meet specifications.

 

3. Carrier Frequency Setting Too High:

Symptom: Setting the carrier frequency too high to reduce motor noise increases switching losses and heat generation.

Solution: While maintaining quiet operation, lower the carrier frequency to the factory default value or a reasonable level.

 

4. Temperature sensor or detection circuit failure:

Symptom: The radiator temperature is not high, but the alarm continues to sound.

Solution: This is a hardware failure and requires a professional technician to inspect the temperature sensor, its connecting wires, and the detection circuit.