Analysis and Treatment of Abnormal Noise and Vibration During Operation
Abnormal noise and vibration during elevator operation are the main issues affecting ride comfort, and the causes can be divided into mechanical and electrical categories. Mechanical causes and treatment: (1) Poor guide rail lubrication or worn guide shoes: check the lubrication condition of the guide rail surface, replenish guide rail oil (dosage 5-10 drops/m, cycle 1-2 months) or replace the guide shoe liner (replace when wear exceeds 1/3); (2) Guide rail joint steps: use a guide rail file or angle grinder to grind the joint to a smooth transition (treatment is required when step height >0.05mm); (3) Uneven wear of traction sheave grooves: apply red lead powder to the wire ropes and observe the contact marks in the sheave grooves after operation; if uneven, turn the sheave grooves (turning amount not exceeding 1/5 of the rope diameter); (4) Excessive clearance between the car guide rail seat and guide shoe: adjust the guide shoe spring pressure so that the clearance is controlled at 0.2-0.5mm. Electrical causes: (5) Improper inverter parameter settings (speed loop gain too high or too low) causing operational vibration; inverter parameter auto-tuning must be performed again; (6) Signal interference of the traction motor encoder: check the cable shielding layer grounding and cable routing (keep away from the inverter output cable).
Leveling Accuracy Out of Tolerance and Adjustment
Leveling accuracy is an important indicator of elevator comfort, and the standard requires leveling error not to exceed ±10mm (GB 10058-2009). Causes and treatment of inaccurate leveling: (1) Rotary encoder failure: encoder pulse loss or unstable signal leads to inaccurate speed feedback. Check encoder installation and connection cables (reliable shielding layer grounding), and replace the encoder if necessary (incremental encoder recommended, resolution 1024P/R or above); (2) Unstable brake braking torque: loose brake pull rod spring or improper adjustment causes stopping position deviation. Adjust the brake spring force to make the braking torque uniform, with clearance controlled at 0.1-0.3mm; (3) Wire rope slippage: insufficient friction between wire rope and traction sheave groove (mostly during startup or braking). Check rope groove wear and wire rope lubrication (excessive grease on the wire rope surface reduces friction), and clean the wire rope or machine the rope groove if necessary; (4) Floor sensor position deviation: position deviation of bistable magnetic switches or photoelectric switches. Readjust and secure the sensor position. Leveling adjustment should be performed under both no-load and full-load conditions, and the intermediate value should be used for setting.
Diagnosis and Elimination of Door Opening/Closing Faults
Elevator door opening/closing faults are the most common type of elevator fault, accounting for about 40%-50% of total elevator faults. Common faults and treatment: (1) Loose door operator belt: door opening/closing speed becomes slower or stops midway. Check belt tension (press the midpoint of the belt with a finger; a depression of 10-15mm is normal); if tension is insufficient, adjust the tension pulley or replace the belt; (2) Dust accumulation or poor lubrication on the door guide rail: abnormal noise or jamming during door opening/closing. Clean the guide rail (wipe with alcohol or neutral detergent), then apply a small amount of lubricating grease (molybdenum disulfide grease); (3) Light curtain safety edge failure: elevator door opens and closes repeatedly (cannot close). Check whether the light curtain transmitter/receiver tubes are blocked or damaged (use an infrared detection card), clean the photoelectric tube surface, and replace the light curtain if necessary (128-beam infrared light curtain recommended, detection distance 1.5-3.0m); (4) Poor contact of door lock contacts: door lock not engaged after the door is closed in position, and the elevator cannot run. Check the door lock contact spring position and contact resistance (should be <0.1Ω), adjust the contact position or replace the contact assembly. Most door opening/closing faults can be prevented through regular maintenance (recommended: clean the guide rail once a month, check the light curtain once a quarter).
Root Cause Analysis and Prevention of Entrapment Faults
Elevator entrapment is the most serious type of accident, and cause analysis should be carried out from multiple dimensions. Common root causes: (1) Door lock system failure (accounting for 35%-40% of entrapment faults): door lock contact oxidation, loose wiring, door lock circuit shorting, etc. Preventive measures: check door lock contact condition and wiring tightness every half month; (2) Safety circuit open circuit (accounting for 20%-25%): overspeed governor false operation, tension pulley switch false operation, emergency stop switch accidentally triggered, etc. Preventive measures: check the installation position and protection of each safety switch to prevent foreign objects from entering; (3) Inverter overload protection (accounting for 15%-20%): motor overload, poor heat dissipation, improper parameters, etc. Preventive measures: check the operating status of cooling fans and regularly clean the heat sink; (4) Power supply fluctuation (accounting for 10%-15%): voltage sag, phase loss, poor neutral wire contact. Preventive measures: install a power voltage stabilizer or UPS (uninterruptible power supply). Establish an entrapment fault database, conduct root cause analysis (RCA) for each entrapment accident, and formulate corrective and preventive measures, which can greatly reduce the incidence of entrapment faults.