Over the past 3-5 days, South China has experienced severe "return to spring" weather, characterized by high humidity levels. This, combined with abundant spring and summer rainfall, results in extremely high air moisture. The combination of humid air and fluctuating temperatures increases the air's electrical conductivity, making machinery prone to malfunctions. This is especially true in dusty environments or those requiring strict dryness; dust combined with humid air can settle on electronic components, easily causing leakage or short circuits. This can easily lead to machine malfunctions, breakdowns, or even burnout. Therefore, we must attach great importance to equipment maintenance and inspection.
01 What are the main types of electrical equipment malfunctions that are prone to occur in humid weather?
Fault 1: Inverter trips, motor grounds.
Fault 2: Abnormal DC power supply, resulting in the inability to provide system control power and the inability of the equipment to work.
Fault 3: Short circuit in contactor contacts, short circuit in power supply causing arcing, short circuit in wiring terminals, circuit breaker tripping, and inability to start the machine.
Fault 4: The programmable logic controller (PLC) program is lost, or the PLC CPU is directly damaged. Dust and moisture increase conductivity, adhering to the battery terminals and causing a semi-short circuit and leakage.
02. How should equipment be maintained in humid weather?
Based on the cases above, how should we maintain our equipment in humid weather? If we carefully follow these points, the failure rate will naturally decrease gradually.
1. Regular Maintenance and Inspection: In some processing industries, dust is ubiquitous, especially fine dust that absorbs moisture and easily adheres to electrical components, posing a "hidden killer." Therefore, before powering on the equipment, check for moisture or condensation on the electrical components. If any is found, dry them with a hairdryer before powering on. It is recommended to use an air hose to clean the dust from all electrical components on the machine, such as PLCs and frequency converters, every two days on average.
2. Check the wiring and terminal screw connections to prevent arcing: Check the wiring for damage, short circuits, or leakage; tighten the contactor terminal screws and wiring terminal screws, and turn on the power only after troubleshooting to prevent poor contact, arcing, and short circuits.
3. Preheat the equipment before operation: It is recommended to run the equipment for at least 40-60 minutes before operation each day. This allows the machine to generate heat and dry the electronic components. Do not run the machine immediately after powering on the inverter; power it on for 20 minutes and observe for any problems before starting operation. Powering on the inverter helps dry the components and prevents malfunctions. This also serves to charge the PLC's CPU battery, which is especially important for older machines.
4. Take precautions against rust: Apply some machine oil to parts of the machinery that are prone to rust to prevent rusting.
5. Implement dust prevention measures: Ensure all electrical components are properly covered, such as the battery cover for the PLC and the outer cover of the frequency converter. Check the exhaust fan of the electrical cabinet for damage; replace it immediately if it is broken. Keep the electrical cabinet door closed and check the sealing gaskets for integrity. Minimize dust entry into the electrical cabinet.
6. Take precautions against moisture: Place desiccants in the electrical cabinets to reduce air humidity, and replace the desiccants frequently; if possible, install dehumidifiers in the workshop to reduce humidity and prevent condensation on electrical components.
03 Routine Inspection and Maintenance Items for Frequency Converters
