Step 1: Establish policies first and create maintenance records
1. Improve operating and maintenance procedures: Develop clear daily operating guidelines and maintenance roadmaps for operators to provide a solid foundation for maintenance work.
2. Establish equipment health records: Create individual maintenance records for each piece of equipment, detailing the "operating time," "abnormal conditions," "maintenance tasks," and "replaced parts" for each instance. This not only provides a clear record of maintenance history but also serves as a valuable database for "preventive maintenance," enabling accurate prediction of replacement cycles for wear-prone parts.
3. Implement a system of accountability for professionals: Clearly define the responsibilities of operators, maintenance technicians, and team leaders to establish a tiered management system where each role fulfills its specific duties, ensuring that maintenance tasks are effectively carried out.
Step 2: Drill down layer by layer to perform three-level maintenance
1. Basic Level: Daily Inspections and Cleaning (Recommended: Before and after each shift)
Core Principle: Ensure the basic safety of the electrical system environment through frequent, quick "look, listen, and check" procedures.
Key Procedures:
Environmental Monitoring: Ensure the ambient temperature inside the electrical control cabinet is ≤40°C and maintain dust protection. Listen for any unusual noises from the fans and check if the airflow feels normal to determine if heat dissipation is effective.
Visual Inspection: Check all indicator lights and touchscreens for fault alerts. Sniff for any unusual odors and inspect wiring for loose connections, damage, or signs of burning.
Cleaning and Maintenance: After disconnecting power, use a vacuum cleaner or soft-bristle brush to remove dust from the interior and exterior of the electrical control cabinet. Never use a damp cloth or high-pressure air gun.
2. Core Level: In-Depth Inspection and Prevention (Recommended: Weekly/Monthly/Quarterly)
Core Principle: Comprehensive coverage, thorough inspection, and prevention of potential issues.
Key Procedures:
Power Supply and Wiring: Check whether the voltage in the main and control circuits is stable, and inspect the status of protective devices such as fuses and circuit breakers.
Safety and Grounding: Test emergency stop buttons and safety interlock devices. Periodically inspect equipment grounding; standards require grounding resistance ≤4Ω.
Core Components: Check the status of the main PLC's I/O indicator lights and communication interfaces. Use an infrared thermometer to scan critical components such as contactors and variable frequency drives (VFDs). Inspect all sensors and calibrate temperature control instruments to match actual temperatures.
Scheduled Component Replacement: For "wear-and-tear parts" with a limited lifespan-such as relays, cooling fans, and heating coils-proactively replace them before the end of their service life based on operating hours and manufacturer recommendations to prevent unexpected downtime.
3. Professional Level: Troubleshooting and Diagnosis (When Anomalies Occur)
Basic Principle: Follow a troubleshooting approach that prioritizes external over internal components and power supply over load. At the same time, draw on the advanced concept of "condition-based maintenance" to use professional instruments to assess equipment health, rather than relying solely on fixed maintenance cycles, thereby improving maintenance efficiency and accuracy.
Thinking Framework:
Listen for sounds: Check for abnormal noises.
Look for signs: Check indicator light colors and look for burn marks.
Smell for odors: Check for the smell of burnt insulation.
Common Tools: Multimeter, clamp meter, infrared thermometer, oscilloscope.
Specific Methods: Narrow down the scope through logical reasoning; perform replacement tests on suspect components or isolate sections of the circuit to pinpoint the issue.
Troubleshooting Priority: Troubleshoot in the following order: 'Power Supply' ➜ 'External Wiring' ➜ 'Motor Load' ➜ 'Control Logic'.
Precautions: Always disconnect power and verify absence of voltage before repair; label components before disassembly; and maintain detailed repair records.
Step 3: Make safety the top priority
Standard Procedures to Be Followed:
Complete Power Shutdown: Before performing any inspection or maintenance involving the interior of the electrical cabinet, the main power supply to the equipment must be turned off, and the "Power Off – Test for Voltage – Tag – Lockout" procedure must be followed. Equipment such as variable frequency drives (VFDs) may retain residual high voltage after power is disconnected; wait at least 5 minutes or longer until the residual charge has fully dissipated.
Proper Handling: Do not touch electrical components with wet hands. When replacing components such as relays, use appropriate tools.
Personal Protective Equipment: Operators must wear safety workwear, safety shoes, and other protective gear. Dust generated during cleaning may also be harmful; it is recommended to wear a dust mask.
Follow the Correct Sequence: Strictly adhere to the startup sequence of "turn on the heater first, then start the main unit," and perform the warm-up step of "running the main unit at low speed for 5 minutes."