How should explosion-proof motors be properly maintained?

Proper maintenance of explosion-proof motors is a critical component of ensuring workplace safety in high-risk environments. The key lies in systematically conducting daily inspections and regular professional maintenance, with particular emphasis on the cleanliness of the explosion-proof surfaces and the compliance of bolt tightening torques.

I. Daily Operational Inspections: Timely Identification of Potential Hazards

This serves as the first line of defense in maintenance and is recommended to be performed daily. Key areas of focus include:

Visual Inspection: Check the housing for cracks, deformation, or corrosion; ensure the explosion-proof marking is clear and the junction box seal is intact.
Operational Monitoring: Listen for abnormal vibrations, friction noises, or a burning smell; shut down the motor immediately if any abnormalities are detected.
Cleaning: Use a dry, explosion-proof brush to remove surface dust, keep heat dissipation channels clear, and prevent excessive temperature rise caused by dust accumulation.
II. Regular Professional Inspections: Comprehensive Assurance of Explosion-Proof Performance

In accordance with the GB/T 3836.16-2017 standard, it is recommended to conduct a detailed inspection every quarter to once a year. The core requirements are as follows:

1. Cleaning and Condition Inspection of Explosion-Proof Joints
Cleaning Requirements: Wipe the explosion-proof joint surfaces with a lint-free soft cloth dampened with explosion-proof cleaning agent. Never use water or ordinary solvents for rinsing.
Damage Assessment:
The surface should be flat and smooth, free of scratches, dents, or corrosion;
If the corroded area exceeds 30%, the component must be replaced;
Gaps must comply with national standards (e.g., the gap at M20 threaded joints must be ≤0.3 mm).
Seal Integrity Test: The kerosene penetration method may be used for testing—if no leakage is detected 10 minutes after applying kerosene, the test is considered passed.
2. Torque Verification for Fastening Bolts
Inspection Frequency: Verification must be performed after every maintenance or operation in a vibrating environment.
Operating Procedures:
Use a digital torque wrench to tighten bolts evenly in a diagonal sequence, ensuring consistent force distribution;
Bolt insertion depth must be ≥1.5 times the diameter to prevent flange deformation;
Anti-loosening components such as spring washers and threadlocker must be intact.
Torque Standards: Set according to the equipment manual or industry standards. For example, the torque for explosion-proof flange bolts is typically no less than 50 N·m; specific values should be referenced in the original manufacturer’s technical documentation.
3. Other Key Items
Bearings and Lubrication: Monitor operating sounds and replenish specialized grease to fill 1/3 to 1/2 of the bearing cavity, avoiding overheating caused by excessive grease.
Electrical Performance Testing:
Winding insulation resistance: ≥5 MΩ for 660 V motors, ≥10 MΩ for 1140 V motors;
Three-phase current imbalance ≤10%;
Ground resistance ≤0.1 Ω.
Seal Inspection:
Aged or cracked seals must be replaced; oil-resistant and high-temperature-resistant materials (such as fluorocarbon rubber) are recommended.