Elevator Fault Categories
Design, Manufacturing, and Installation Faults
After an elevator fault occurs, maintenance personnel should first identify the affected component and determine the root cause. If the issue is related to design defects, manufacturing quality, or installation errors, the system should not be adjusted blindly. Contact the manufacturer or the installation and maintenance provider before corrective work begins.
Operational Faults
These faults result from improper operation or misuse. Common examples include unauthorized manipulation of safety devices, switches, or control functions.
Component Failure Faults
Component-related failures are among the most common elevator problems. Mechanical issues may involve friction, wear, or transmission damage. Electrical failures often include burned contactor contacts, damaged relays, overheated resistors, or failed electronic components.
Elevator Troubleshooting Guide
Elevator models and control systems vary by manufacturer. The following examples are based on common elevator configurations and are intended as general troubleshooting references.
1. Elevator Does Not Start
| Possible Cause | Corrective Action |
|---|---|
| Main power switch is not connected | Connect the power supply and restore three-phase AC power |
| Supply voltage is below 330V, preventing relay operation inside the control cabinet | Restore normal supply voltage and stabilize power quality |
| One phase of the 380V three-phase power supply is disconnected | Restore the missing power phase |
| Incorrect phase sequence prevents the phase relay from operating | Inspect and correct the phase sequence |
| Car door or landing door is not fully closed | Inspect and close all doors properly |
| Door interlock switch failure | Repair or replace the switch or contacts |
| Emergency exit door or safety door is open, or its safety switch has failed | Close the safety door and inspect or replace the safety switch |
| Safety switch or governor switch has not reset after activation | Reset the switch or replace defective components |
| Emergency stop button remains activated or damaged | Reset or replace the emergency stop switch |
2. Elevator Starts With Heavy Resistance and Reduced Speed
| Possible Cause | Corrective Action |
|---|---|
| Brake shoes do not release completely | Inspect the brake circuit and adjust the brake assembly |
| Brake clearance is too small | Adjust brake clearance to approximately 0.5mm |
| DC brake coil is damaged or disconnected | Inspect wiring or replace the coil |
| Brake DC power voltage is too low | Restore proper DC supply voltage |
| Poor contact in one phase of the traction motor power supply | Tighten wiring connections and eliminate poor contact |
| Motor contactor contacts are not engaging properly | Inspect or replace the contactor |
| Power supply voltage is too low | Restore voltage and limit voltage drop within 5% |
| Gear reducer lubrication failure or bearing clearance problem | Repair the reducer and replace lubricant |
| Guide rails are misaligned or loose | Realign guide rails and correct joint displacement |
3. Traction Rope Slippage and Overspeed Downward Movement
| Possible Cause | Corrective Action |
|---|---|
| Brake torque is insufficient | Inspect and readjust the brake system |
| Counterweight is too light | Rebalance the counterweight system |
| Counterweight is too heavy | Perform balance correction |
| Elevator car is overloaded | Reduce load and operate within rated capacity |
| Excessive lubrication on traction sheave or ropes | Remove excess lubricant |
| Insufficient rope wrap angle on the traction sheave | Adjust guide pulley position to increase wrap angle |
| Traction sheave groove wear or incorrect groove profile | Re-machine or replace the traction sheave |
| Governor or safety gear fails to operate | Repair or replace defective safety components |
4. Elevator Shows Upward Direction but Does Not Move Up
| Possible Cause | Corrective Action |
|---|---|
| Faulty floor selection button or up relay | Inspect and replace defective relays, switches, or wiring |
| Upward limit switch does not reset | Inspect directional contactors and limit switches |
5. Elevator Shows Downward Direction but Does Not Move Down
| Possible Cause | Corrective Action |
|---|---|
| Faulty floor selection button or down relay | Inspect and replace defective relays, switches, or wiring |
| Downward limit switch does not reset | Inspect directional contactors and limit switches |
6. Elevator Runs in the Opposite Direction After Power Restoration
| Possible Cause | Corrective Action |
|---|---|
| Incorrect external three-phase power sequence and no phase protection device installed | Correct the phase sequence or install a phase protection device |
7. Dual-Speed Elevator Cannot Operate at Low Speed
| Possible Cause | Corrective Action |
|---|---|
| Slow-speed contactor failure | Repair or replace the contactor |
| Switching distance between high and low speed is too short | Adjust switching distance and selector alignment |
| Reed switch failure | Replace the reed switch |
| Directional relay or floor relay does not release | Inspect and replace defective relays |
8. Friction Noise During Elevator Operation
| Possible Cause | Corrective Action |
|---|---|
| Guide shoe liner wear | Replace the liner and adjust guide shoe pressure |
| Foreign objects inside guide shoes | Remove debris |
| Safety gear clearance is too small | Adjust clearance according to manufacturer specifications |
| Door vane rubs against landing sill | Inspect car alignment and adjust if necessary |
| Uneven wear on traction sheave grooves | Re-machine or replace the sheave |
| Uneven tension among wire ropes | Replace damaged ropes and rebalance tension |
| Dirt or debris on guide rails | Clean and lubricate guide rails |
| Excessive clearance between guide rails | Adjust guide shoes to proper clearance |
9. Elevator Leveling Problems
| Possible Cause | Corrective Action |
|---|---|
| Insufficient braking force | Adjust brake spring pressure and brake clearance |
| Excessive braking force | Readjust brake spring pressure |
| Counterweight imbalance | Rebalance the counterweight system |
| Low leveling accuracy due to insufficient regenerative braking | Adjust low-speed switching settings |
| Incorrect leveling sensor position | Adjust sensor and leveling plate distance |
| Burned contactor contacts or residual magnetism | Replace contacts or coils |
| Elevator requires repeated re-leveling | Adjust brake torque and leveling sensor clearance |
| Reed switch failure | Replace the reed switch |
| Brake malfunction | Inspect and adjust the brake system |
10. Elevator Door Opening and Closing Problems
| Possible Cause | Corrective Action |
|---|---|
| Door operator motor failure | Repair or replace the motor |
| Door open limit switch fails to reset | Inspect and restore switch operation |
| Door contactor failure | Replace the contactor |
| Door relay does not energize | Inspect relays and control wiring |
| Door closing motor or contactor failure | Repair or replace defective components |
| Door closing limit switch does not reset | Inspect and correct switch operation |
| Door movement becomes slow or unstable | Adjust resistance value or inspect slipping belts and pulleys |
| Door rollers are worn | Replace rollers and adjust guide rails |
| Debris inside door sill track | Clean the sill track |
| Door safety edge fails | Repair or replace the microswitch or transmission mechanism |
11. Floor Selection Faults
| Possible Cause | Corrective Action |
|---|---|
| Elevator skips selected floors | Replace faulty selector relays or adjust selector contacts |
| Elevator stops at unselected floors | Inspect relay contacts inside the speed control circuit |
| Floor buttons fail or do not reset | Inspect wiring, relays, and button alignment |
| Isolation diode connection error | Correct or replace the diode |
12. Governor and Safety Gear Faults
| Possible Cause | Corrective Action |
|---|---|
| Governor activates unexpectedly | Inspect governor springs and rotating shaft lubrication |
| Safety gear activates below rated speed | Recalibrate governor activation speed |
| Guide rail displacement reduces safety gear clearance | Realign and correct guide rail installation |
| Safety gear does not activate during overspeed | Inspect governor, wire rope, and linkage mechanism |
13. Signal Lights Do Not Illuminate
| Possible Cause | Corrective Action |
|---|---|
| Burned lamp | Replace the lamp |
| Loose or disconnected wiring | Tighten and reconnect wiring points |
14. Main Fuse Frequently Blows
| Possible Cause | Corrective Action |
|---|---|
| Incorrect fuse rating | Replace with properly rated fuse |
| Contactor sticking or poor contact | Repair or replace the contactor |
| Excessive starting or braking time | Adjust acceleration and braking settings |
| Loose resistor or reactor terminals | Tighten terminal connections |
15. Partial Circuit Fuse Frequently Blows
| Possible Cause | Corrective Action |
|---|---|
| Circuit grounding fault | Inspect insulation and eliminate grounding points |
| Relay insulation breakdown | Improve insulation or replace the relay |
Three-Phase Induction Motor Troubleshooting Guide
1. Motor Does Not Start
| Possible Cause | Corrective Action |
|---|---|
| Overcurrent relay setting is too low | Increase the relay setting appropriately |
| Excessive load or mechanical blockage | Reduce the load and inspect the mechanical transmission system |
| Severe bearing wear causes uneven air gap and rotor locking | Inspect and replace bearings |
| Incorrect slot matching between stator and rotor | Adjust rotor diameter or rewind the rotor according to specifications |
2. Motor Speed Drops Under Load
| Possible Cause | Corrective Action |
|---|---|
| Excessive load | Reduce the operating load |
| Supply voltage is below the rated value | Inspect and restore the correct voltage |
3. Motor Housing Becomes Electrically Live
| Possible Cause | Corrective Action |
|---|---|
| Moisture inside motor windings or insulation aging | Dry the windings or replace severely aged insulation |
| Metal debris inside stator slots damages insulation | Remove debris and repair damaged insulation |
| Winding ends contact the motor housing | Apply insulation varnish and install insulating material |
| Slot insulation damage at stator core ends | Repair insulation and dry the windings |
4. Abnormal Motor Noise
| Possible Cause | Corrective Action |
|---|---|
| Rotor and stator rubbing against each other | Correct the air gap and inspect bearings |
| Single-phase operation causes humming noise | Inspect fuses and switch contacts |
| Rotor rubs against insulation paper | Trim damaged insulation paper |
| Bearing lubrication failure | Clean and lubricate bearings |
| Bearing damage | Replace bearings |
5. Motor Vibration
| Possible Cause | Corrective Action |
|---|---|
| Rotor imbalance | Rebalance the rotor |
| Bent shaft | Straighten or replace the shaft |
| Broken rotor conductor bars | Perform short-circuit testing and repair defects |
| Uneven air gap creates magnetic pull | Adjust the air gap evenly |
6. Bearing Overheating
| Possible Cause | Corrective Action |
|---|---|
| Bearing damage | Replace the bearing |
| Improper bearing fit on the shaft | Correct the shaft tolerance |
| Loose or slow oil ring movement in sleeve bearing | Repair or replace the oil ring |
| End cover or bearing cover misalignment | Reinstall and align the covers properly |
7. Excessive Motor Temperature or Smoke
| Possible Cause | Corrective Action |
|---|---|
| Cooling air passages are blocked | Remove dust and oil contamination |
| Supply voltage is too high or too low | Inspect and adjust the voltage |
| Incorrect winding connection | Check winding polarity and correct wiring |
| Excessive air gap between stator and rotor | Replace the rotor or correct the air gap |
| Bearing wear causes rotor misalignment | Replace worn bearings |
8. Severe Three-Phase No-Load Current Imbalance
| Possible Cause | Corrective Action |
|---|---|
| Unequal turns in rewound stator windings | Rewind the stator windings |
| Incorrect internal stator wiring | Inspect polarity and correct wiring |
9. Excessive No-Load Current
| Possible Cause | Corrective Action |
|---|---|
| Excessive motor air gap | Readjust the air gap |
| Insufficient winding turns | Rewind the stator with the correct number of turns |
| Improper motor assembly | Reassemble and correct rotor alignment |
| Lubricant has dried out | Replace the lubricant |
10. Low Insulation Resistance
| Possible Cause | Corrective Action |
|---|---|
| Moisture or water ingress | Dry the motor after insulation testing |
| Excessive dust and contamination on windings | Clean and re-varnish the windings |
| Damaged lead wire insulation | Re-insulate the wiring connections |
| Insulation aging caused by overheating | Re-varnish or replace the winding insulation |
DC Motor Troubleshooting Guide
1. Excessive Sparking at the Brushes
| Possible Cause | Corrective Action |
|---|---|
| Brushes are not positioned on the neutral line | Adjust the brush holder position |
| Poor contact between brushes and commutator | Grind the brush contact surface and operate under light load for proper seating |
| Loose or misaligned brush holder | Tighten or realign the brush holder |
| Brush fit inside the holder is too tight | Slightly reduce brush dimensions |
| Uneven or incorrect brush pressure | Adjust spring pressure or replace the brush holder |
| Rough commutator surface | Clean or polish the commutator |
| Mica insulation protrudes between commutator segments | Undercut and polish the commutator |
| Brushes are excessively worn or incorrect type is installed | Replace with the specified brush type |
| Excessive load causes commutating pole saturation | Restore normal operating load |
| Motor base is loose and causes vibration | Tighten anchor bolts |
| Commutating pole winding short circuit | Inspect and repair winding insulation |
| Armature overheating causes loose commutator connections | Inspect voltage balance between commutator segments and reweld loose connections |
| Commutating pole winding polarity is reversed after maintenance | Correct the winding polarity according to the wiring sequence |
| Uneven brush holder positioning causes unequal current distribution | Readjust brush holder spacing evenly |
| Rotor balance is incorrect | Rebalance the rotor |
2. Generator Voltage Cannot Build Up
| Possible Cause | Corrective Action |
|---|---|
| Residual magnetism has disappeared | Apply external DC excitation to restore magnetism |
| Incorrect rotation direction | Reverse the rotation direction |
| Field winding polarity is reversed | Correct the field winding connection |
| Open circuit in field winding | Inspect field winding and rheostat connections |
| Armature short circuit | Inspect commutator and armature winding for short circuits |
3. Generator No-Load Voltage Is Below Rated Value
| Possible Cause | Corrective Action |
|---|---|
| Field rheostat resistance is too high | Reduce the rheostat resistance |
| Excitation current is below rated value | Increase the excitation current |
| Partial short circuit in shunt field winding | Repair or replace the affected winding |
| Brushes are not positioned on the neutral line | Adjust the brush holder position |
4. Generator Voltage Drops Significantly Under Load
| Possible Cause | Corrective Action |
|---|---|
| Brushes are not positioned correctly | Adjust brush holder alignment |
| Commutating pole winding polarity is reversed | Reverse the winding connection |
| Incorrect installation sequence of main poles and commutating poles | Inspect magnetic pole sequence and correct installation |
5. DC Motor Does Not Start
| Possible Cause | Corrective Action |
|---|---|
| No current supply | Inspect wiring, controller connections, and fuses |
| Excessive load | Reduce the operating load |
| Poor brush contact | Inspect spring pressure and improve brush contact |
| Open circuit in excitation circuit | Inspect and replace damaged field windings |
| Excessive motor speed with severe sparking | Inspect field winding and speed controller connections |
6. Abnormal Motor Speed
| Possible Cause | Corrective Action |
|---|---|
| Brushes are not positioned on the neutral line | Adjust brush holder position |
| Short circuit in armature or field winding | Inspect winding resistance and repair short circuits |
| Excessive resistance in field circuit | Inspect rheostat and field winding connections |
| Long-term overload operation | Restore normal operating load |
7. Armature or Armature Winding Smokes
| Possible Cause | Corrective Action |
|---|---|
| Short circuit in commutator or armature | Inspect for short circuits or metal debris |
| Motor terminal voltage is too low | Adjust the generator output voltage |
| Rotor and stator rubbing against each other | Inspect bearing condition and air gap alignment |
8. Field Coil Overheating
| Possible Cause | Corrective Action |
|---|---|
| Motor speed is too low | Increase speed to rated value |
| Partial short circuit in field winding | Replace damaged winding |
| Terminal voltage exceeds rated value for extended periods | Adjust voltage to the rated value |
9. Electrical Leakage at the Motor Housing
| Possible Cause | Corrective Action |
|---|---|
| Low insulation resistance | Test insulation resistance and dry the motor if below specification |
| Lead wire contacts the housing | Repair the damaged wire |
| Damaged insulation on terminal board or windings | Restore insulation protection |
| Defective grounding system | Repair the grounding connection |
10. Abnormal Bearing Operation
| Possible Cause | Corrective Action |
|---|---|
| Excessive lubrication or incorrect lubricant type | Replace with suitable lubricant |
