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Overhead Crane Electrical System Maintenance and Troubleshooting Methods

February 02, 2024

Crane electrical systems is a more complex part of the overhead crane maintenance, electrical in the impact, vibration and oscillation of the working conditions of the operation, easy to eot crane electrical failure, especially in the high temperature, dusty, humid and other harsh environments, it is more likely to fail and may cause accidents. When maintaining the bridge crane electrical system, we need to pay attention to all aspects to ensure the reliability and safety of the equipment.

Crane electrical system failure causes and maintenance

Failure Phenomenon1: Close the power switch, press the button, the contactor is not absorbed, the crane can not be started

Cause of Failure:

  1. No power from power supply
  2. Fuse is blown
  3. Cam controller handle is not in the zero position, zero position protection contact broken
  4. Contactor itself is damaged
  5. Contacts of emergency switch are not closed.  
  6. Hatch switch, beam railing door switch disconnected not closed

Maintenance treatment:

  1. Use the AC voltage block of the multimeter to measure whether there is voltage at the inlet terminal of the power switch, and give treatment when the voltage is not normal.
  2. Replace the new fuse
  3. Put all three cam controller handles in zero position.
  4. Replace the contactor
  5. Operate to make it close
  6. Close the hatch and the railing door so that they are all in a closed state.
Maintenance measures:Check whether the contact of each electric appliance (cam controller or master command controller, linkage controller and contactor, etc.) is normal, whether the current passes normally, and whether the handle position is returned to the position.
Failure Phenomenon2: After closing the power switch, press the button, the contactor is absorbed, but the overcurrent relay operates

Cause of Failure:

Cam controller has a ground fault

Maintenance treatment:

Use a multimeter and megohmmeter to check cam controllers one by one, to find and eliminate ground faults
Maintenance measures:Check whether the cam controller contacts have burnt hair phenomenon, if necessary, must be timely with metallurgical sandpaper grinding and even replace the contacts after use.
Failure Phenomenon3: The power supply has been turned on, the contactor has been operated to absorb, but the motor does not rotate after the cam controller is awesome zero position.

Cause of Failure:

  1. The moving and static contacts of the cam controller are not in contact or have poor contact.
  2. Damage to the speed control resistor or motor rotor winding
  3. Brushes and sliding contact wires are not in contact or have poor contact.

Maintenance treatment:

  1. Adjust the contact of cam controller or replace cam controller.
  2. Repair or replace the speed control resistor or motor.
  3. Adjust the contact state of brush and slide contact wire to make it back to normal
Maintenance measures:Check whether the contacts of each electric appliance (cam controller or master command controller, linkage controller and contactor, etc.) have burnt hair phenomenon, if necessary, it must be promptly sanded with metallurgical sandpaper and even replace the contacts after use.
Failure Phenomenon4: Motor brushes produce sparks exceeding the specified level or the slip rings are burnt.

Cause of Failure:

  1. Poor brush contact or oil contamination
  2. Brush contact too tight or too loose
  3. Replacement of brush specification is not correct during maintenance.

Maintenance treatment:

  1. Repair the brushes to ensure good contact.
  2. Adjust the brush spring to make the brush have normal contact pressure.
  3. Replace the brushes
Maintenance measures:Regularly check the slip ring, carbon brush holder, long time use will appear collector ring or brush abnormal wear and tear, brush vibration and produce sparks and other ills
Failure Phenomenon5: High sparks and severe burns between the movable and static contacts of the cam controller

Cause of Failure:

Improper contact pressure or burrs on cam controller moving and static contacts

Maintenance treatment:

Adjust contact pressure, deal with burrs, or replace movable or static contacts.
Maintenance measures:Check whether the contacts of each electric appliance (cam controller or master command controller, linkage controller and contactor, etc.) have burnt hair phenomenon, if necessary, it must be promptly sanded with metallurgical sandpaper and even replace the contacts after use.
Failure Phenomenon6: Insufficient motor output, slow speed

Cause of Failure:

  1. Brake solenoid is not completely released
  2. Reduced grid voltage
  3. There is a mechanical stagnation phenomenon

Maintenance treatment:

  1. Check and adjust the brake solenoid
  2. Adjust the load or exclude the cause of low voltage
  3. Rule out mechanical problems
Maintenance measures:Check whether the dragging motor of each organization is overheated at any time, and observe the operation of the motor frequently to see if there is any abnormality.
Failure Phenomenon7: Armature does not reset after the solenoid is de-energized

Cause of Failure:

  1. Motor is stuck
  2. Iron core surface has oil sticking to it
  3. Lubricating oil freezes during cold season

Maintenance treatment:

  1. Refurbish the mechanism
  2. Remove the oil on the iron core surface
  3. Handle or replace the lubricating oil
Maintenance measures:Clean internal parts, observe wear and tear on motor parts (e.g., brush holders and slip rings), and check for abnormal sounds during operation. Check and repair controls and switch contacts as needed.
Failure Phenomenon8: Problems such as the crane not being able to stop during operation or swaying when stopped
Cause of Failure:Brake failure Maintenance treatment:Replacement of brakes
Maintenance measures:Check the working condition of the brake and replace it if there is any problem.

The above recommendations should be adapted to the specific bridge crane model and manufacturer’s recommendations. When carrying out maintenance, please ensure that the work is performed in accordance with the relevant safety regulations and standard operating procedures. Degong Crane has professional electrical engineers, so if you have any problems, you can seek help from us.

Zora Zhao

Expert in Overhead Crane/Gantry Crane/Jib Crane/Crane Parts Solutions

With 10+ years of experience in the Crane Overseas Export Industry, helped 10,000+ customers with their pre-sales questions and concerns, if you have any related needs, please feel free to contact me!

WhatsApp: +86 158 3611 5029
Email: zorazhao@dgcrane.com
bridge crane,eot crane,overhead crane,Overhead Crane Electrical System

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