Electric Motor Industry: Comprehensive Maintenance Guide for High-Voltage Motors
I. Introduction
High-voltage motors serve as the "heart" of industrial operations, driving critical processes from mining and steel production to petrochemical refining and power generation. Their reliable performance is essential for maintaining continuous production. For instance:
Mining Operations: Crushers and hoists rely on high-voltage motors for steady, robust power to ensure efficient ore extraction.
Steel Production: Rolling mills depend on precise motor drives to shape molten steel into high-quality products.
A single hour of motor downtime in large-scale production lines can incur direct economic losses of hundreds of thousands of yuan, with cascading impacts on supply chains and customer commitments. Ensuring motor reliability is thus paramount.
II. Daily Maintenance Protocols
(A) Thorough Cleaning
Dust and oil accumulation on motors act like a "dirty coat," reducing heat dissipation and risking electrical faults.
Body Cleaning:
Wipe motor surfaces daily with soft cloths in dusty environments (e.g., cement plants, mines).
Ensure cooling fins remain unobstructed for optimal "breathing."
Terminal Block Cleaning:
Brush terminals gently to remove dust.
Clean with isopropyl alcohol to eliminate oxidation, ensuring stable current transmission.
Starter Device Cleaning:
Remove dust from starters and inspect contacts for burn marks.
Verify grounding connections to guarantee safe startup.
(B) Component Inspections
Regular checks of critical components prevent minor issues from escalating.
Fastening Screws:
Tighten foundation, end cover, and bearing cover screws to specified torque.
Address loosening immediately to avoid vibration-induced damage.
Drive Systems:
Belt Drives: Adjust tension and inspect for wear/cracks.
Couplings: Check for misalignment or damage.
Terminal Boxes:
Inspect wiring screws for looseness or burns. Tighten or replace as needed.
Bearings:
Monitor for abnormal noises (e.g., grinding) or overheating.
Address issues promptly via lubrication or replacement.
III. Periodic Deep Maintenance
(A) Insulation System Evaluation
Insulation degradation accounts for >60% of motor failures. Key steps include:
Insulation Resistance Testing:
Use a 2500V megohmmeter for high-voltage motors.
Minimum resistance: 1 MΩ/kV (at 40°C ambient before commissioning).
Moisture Control:
Detect humidity via visual inspection or meters.
Dry windings using ovens or hot-air blowers (≤120°C).
Grounding Verification:
Ensure grounding resistance <4Ω for safety compliance.
(B) Bearing Care
Bearings require meticulous care to extend service life:
Lubrication Schedule:
Relube every 3–6 months; more frequently in dusty environments.
Fill bearing spaces 1/3–1/2 full with grease.
Replacement Criteria:
Replace if radial play exceeds limits or abnormal noise/heat persists.
Install new bearings with proper fits and end-cover seals to prevent lubricant leakage.
IV. Fault Diagnosis & Solutions
(A) Common Failure Modes
Cooling System Failures:
Leaky cooling pipes reduce heat dissipation, risking "cylinder burst" in high-temperature environments.
Rotor Defects:
Welding fractures in rotor bars cause vibration and current fluctuations.
Stator Winding Issues:
Mechanical vibrations wear insulation, leading to phase-to-phase discharge.
Bearing Failures:
Poor lubrication or misalignment results in overheating or seizure.
Insulation Breakdown:
Humidity or thermal aging degrades insulation, risking short circuits.
(B) Mitigation Strategies
Cooling System Repairs:
Weld cracked pipes and install filters to block debris.
Rotor Repairs:
Re-weld broken bars and clear debris from slots.
Stator Winding Fixes:
Re-insulate damaged sections using class-appropriate materials (e.g., mica tape).
Bearing Management:
Select bearings matching load/speed specs and ensure precision installation.
Insulation Restoration:
Dry moisture-affected motors or replace degraded insulation.
V. Conclusion
Proactive maintenance is the cornerstone of high-voltage motor reliability. By adhering to daily cleaning, component inspections, and periodic deep maintenance—coupled with swift fault resolution—industries can minimize downtime, extend motor lifespan, and safeguard production continuity. Partnering with motor experts ensures tailored maintenance strategies, optimizing performance in demanding industrial environments.
