Maintenance and repair of inverters and soft starters - Database & Sql Blog Articles

Maintenance and inspection of inverters and soft starters are essential practices to avoid unexpected failures. To ensure effective maintenance, it's recommended to create an inspection checklist that records changes in the device’s characteristics and component stability. This helps prevent malfunctions and makes troubleshooting easier when issues occur. Maintenance can be categorized into daily inspections and periodic checks. During the initial installation phase, it's important to conduct more frequent inspections to identify and address early-stage problems. As the equipment operates over time, regular checks on component degradation become crucial.

1. Preparation Steps for Inspection and Maintenance:

• Turn off the device
• Switch off the main power supply
• Turn off the control power supply
• Confirm that the main circuit is fully discharged
• Perform a voltage check

2. Daily Inspection:

Frequency: Once a month.

Key Items to Check:

• Verify the installation environment—temperature, humidity, presence of gases or dust
• Listen for unusual noises from reactors, transformers, and cooling fans
• Check for any strange odors, especially from insulation materials
• Inspect internal contamination and adjust cleaning frequency based on dirt level

Visual checks are the main focus. If any abnormalities are found, they should be addressed immediately.

3. Periodic Inspection:

Frequency: Based on the unit’s minor repair schedule.

Items to Check:

• Clean the cabinet and internal components
• Check for discoloration, deformation, or leakage in circuit parts (capacitors, reactors, transformers)
• Inspect the substrate for damage, aging, or contamination
• Check wiring for discoloration or corrosion due to heat
• Ensure all fastening parts (bolts, nuts) are secure

When inspecting the main circuit, wait at least 5 minutes after power is turned off. Capacitors may still hold a charge, posing an electric shock risk. Never open the cabinet while the equipment is running.

4. Key Maintenance Focus Areas:

1. Cleaning and maintenance of both the main and control circuits. Start with cleaning, ensuring the power is off and the main circuit has no voltage. Use suction or air blowing to remove dust, but avoid high-pressure air to prevent damage. Wipe non-removable debris with a cloth. Begin from the top and work downward to avoid missing falling particles.

2. Cabinet and Structural Components:

• Cooling Fan: Check airflow and noise levels. After reassembly, ensure bolts are tightened to prevent vibration damage.
• Main Circuit Components: Inspect for dust, discoloration, heat, abnormal sounds, and damage. Verify wiring and connections are secure.

3. Printed Circuit Boards (PCBs):

PCBs with integrated circuits and components must be protected from dust, corrosive gases, and temperature fluctuations. Regular cleaning and maintaining a clean environment help reduce failure risks. When cleaning, use brushes to gently wipe surfaces. Avoid dropping PCBs or screws during handling.

Precautions for PCB Maintenance:

• Wait at least 5 minutes before starting work
• Remove all connectors and wires before taking out the board
• Handle carefully to avoid dropping
• Reinstall in reverse order of removal
• Store boards with the aluminum frame down to prevent short circuits

5. Step-by-Step Inspection and Maintenance Procedure:

1. Stop the unit and confirm the motor has stopped completely
2. Press the stop button on the operator panel
3. Disconnect the external main power supply
4. Confirm the control panel power indicator is off
5. Turn off the control power switch
6. Wait for more than 5 minutes
7. Open the inverter or soft starter cabinet door
8. Check the main input terminals for safe voltage levels
9. Ensure all LEDs on the unit are off
10. Verify there is no voltage on the external control cables
11. Ground the main circuit input
12. Begin inspection and maintenance

If replacing a unit, refer to the specific inverter or soft starter manual.

6. Recovery Steps:

1. Remove the ground wire from the main circuit
2. Turn on the control power and close the cabinet door
3. Power on the external main supply and confirm the control panel is lit
4. Conduct a final safety check before resuming operation