EOT Crane Common Faults and Troubleshooting Methods

1. Brake Failure (Insufficient Braking Torque)

This may result in hook slipping in hoisting mechanisms or travel drifting in traveling mechanisms. Causes and solutions are as follows:

1. Oil contamination on the brake wheel surface reduces the friction coefficient and braking torque.

   → Clean the surface with kerosene or gasoline.

2. Severe wear of brake linings with exposed rivets, causing direct contact with the brake wheel. This reduces braking torque and damages the wheel surface.

   → Replace the brake linings.

3. Improper adjustment of the main spring (low tension), leading to insufficient braking torque.

   → Re-adjust the brake to increase spring tension.

4. Fatigue or aging of the main spring, resulting in reduced elasticity or cracks.

   → Replace and re-adjust the spring.

5. Incorrect brake installation (misalignment between brake frame and brake wheel).

   → Loosen anchor bolts, align the brake, ensure proper contact, then tighten bolts after filling gaps.

6. Improper electromagnet stroke adjustment or obstruction under the lever.

   → Re-adjust stroke or remove obstruction.

7. Hydraulic thruster impeller malfunction, reducing braking force.

   → Adjust and remove blockage to ensure smooth rotation.

2. Brake Cannot Be Released

Possible causes and solutions:

1. Excessive main spring tension exceeding electromagnetic force.

   → Reduce spring tension.

2. Jamming in the brake lever transmission system.

   → Inspect and remove obstruction.

3. Bent brake screw, preventing proper contact with the armature.

   → Straighten or replace the screw.

4. Brake lining sticking to a contaminated brake wheel surface.

   → Clean the wheel surface.

5. Burned electromagnet coil or broken wiring.

   → Replace coil or repair wiring.

6. Hydraulic thruster impeller jammed.

   → Remove blockage.

7. Excessive voltage drop, causing insufficient electromagnetic force.

   → Restore proper voltage.

3. Brake Lining Overheating (Smoking, Burning Smell, Rapid Wear)

1. Improper clearance between lining and brake wheel (too small) causing continuous friction.

   → Adjust clearance to ensure full disengagement during operation.

2. Failure of auxiliary spring (short-stroke brake) causing constant contact.

   → Replace spring and re-adjust.

3. Misalignment between brake frame and wheel.

   → Reinstall to ensure concentricity.

4. Rough brake wheel surface or mismatch with lining.

   → Re-machine or replace the brake wheel.

   
   

4. Unstable Braking Torque

1. Out-of-round brake wheel causing periodic impact.

   → Re-machine or replace.

2. Misalignment between brake frame and wheel.

   → Reinstall and adjust.

5. Gearbox Vibration on the Bridge

1. Loose foundation bolts.

   → Tighten bolts.

2. Misalignment between shafts (motor, gearbox, driven equipment).

   → Re-align components.

3. Insufficient rigidity of support structure causing deformation.

   → Reinforce the structure.

6. Trolley “Three-Wheel” Condition (One Wheel Suspended)

(1) Persistent suspension at all positions:

• Wheel diameter out of tolerance

  → Replace or adjust axle position

• Poor installation accuracy (axles not level)

  → Adjust axle alignment

• Frame deformation

  → Correct frame geometry

(2) Occurs only at certain positions:

• Height difference between main girders

• Poor rail installation (uneven rail height)

  → Adjust rails to meet tolerance

7. Trolley Slipping During Operation

1. Oil, sand, or ice on rail surface

2. Poor wheel installation or insufficient load on drive wheels

   → Adjust wheel position and increase load

3. Rail height difference causing uneven wheel load

   → Adjust rails

8. Trolley Vibration During Startup

Caused by squirrel-cage motor sudden starting, especially with uneven wheel load or suspended wheels.→ Improve wheel alignment or rail installation.

9. Crane Skewing and Rail Gnawing (Severe Wheel Flange Wear / Derailment)

Causes and solutions:

1. Unequal drive wheel diameters

   → Re-machine to equal size

2. Uneven transmission clearance on both sides

   → Adjust and eliminate excessive gaps

3. Poor wheel installation (horizontal misalignment)

   → Adjust to meet tolerance (≤ L/1000)

4. Bridge deformation (diagonal deviation)

   → Correct using flame straightening or wheel adjustment

5. Poor rail installation (height/span deviation)

   → Re-adjust rails

6. Improper brake adjustment on both sides

   → Ensure equal braking force and full release

7. Different motor speeds on both sides

   → Replace motor to achieve synchronization