Maintenance and Troubleshooting Techniques for The Electrical System of Overhead Cranes

The reason for the failure:

Maintenance methods:

1.Power Supply Inconsistent or inadequate power may hinder the proper functioning of the contactor.

1.Verify that the power supply to the crane is stable and within the specified voltage range.

2.Control Circuit Interruption of wiring signal transmission

2. Examine the control circuit for any loose or damaged connections. Ensure that wiring is intact and securely connected to prevent interruptions in the signal transmission.

3.Contactor Malfunction Any loose or damaged connections in the control circuit.

3.Ensure that wiring is intact and securely connected to prevent interruptions in the signal transmission.

4.Verify Control Signals Faulty switches or wiring issues in the control circuit may lead to a lack of signal transmission.

4. Confirm that the control signals from the button and power switch are reaching the contactor.

5.Safety Interlocks Faulty interlocks or sensors can hinder the initiation of crane operations.

5.Check for any safety interlocks that may prevent the contactor from closing.

6.Temperature and Humidity Evaluate the environmental conditions,especially in high-temperature,dusty,or humid environments. These conditions can affect the electrical components.

6.Implement measures such as insulation or environmental controls to mitigate adverse effects.

Maintenance procedures involve inspecting the normal functioning of various electrical components (such as cam controllers, master controllers, linkage controllers, and contactors) to ensure proper contact, normal current flow, and the correct return of handle positions.

The reason for the failure:

Maintenance methods:

The cam controller has a ground fault

Check the cam controller one by one with a multimeter and megger to find and eliminate ground faults.

Maintenance measures: Check whether the cam controller contacts are singed. If necessary, they must be polished with metallographic sandpaper or even replaced before use.

The reason for the failure:

Maintenance methods:

1.The moving and static contacts of the cam controller are not in contact or have poor contact.

1.Adjust the cam controller contact or replace the cam controller.

2.Damaged speed regulating resistor or motor rotor winding

2.Repair or replace the speed controller's resistor or motor.

3.The brush and grinding wire are not in contact, or there is only a poor contact.

3.Adjust the contact status between the brush and the sliding contact wire to return it to the normal state.

Maintenance measures: Check to see if there is any burnt hair on the contacts of each electrical device (cam control, main command control, connection control, contactor, etc.). If necessary, these must be sanded immediately with metal sandpaper and the contacts must also be replaced after use.

The reason for the failure:

Maintenance methods:

1.Poor contact or oil stains on brush

1.Repair brushes to ensure good contact.

2.Brush contact is too stiff or too loose

2.Adjust the brush spring so the contact pressure of the brush is normal.

3.It is incorrect to change brush specifications during maintenance.

3.Replace brushes

Maintenance precautions: Check the slip ring, carbon brush holder regularly, long-term use will cause abnormal wear and tear of the collector ring or brush, brush vibration will cause sparks and other disturbances.

The reason for the failure:

Maintenance methods:

There is insufficient contact pressure or burrs between the moving and stationary contacts of the cam switch.

The contact pressure or ridge between the movable and fixed contacts of the camera switch is insufficient.

Maintenance precautions:Check for burnt hair on the contacts of each electrical device (cam controller, main control controller, linkage controller, contactor, etc.). If necessary, they should be sanded immediately with metal sandpaper and the contacts should be replaced after use.

The reason for the failure:

Maintenance methods:

1.Brake solenoid valve not released completely

1.Inspection and adjustment of brake solenoid valve

2.lower the supply voltage

2.Adjust load or eliminate cause of under voltage

3.There is a mechanical stagnation effect

3.Fix mechanical issues

Maintenance measures: Regularly check the drive motor of each mechanism for overheating and constantly observe the operation of the motor and check for any abnormalities.

The reason for the failure:

Maintenance methods:

1.The engine is stuck

1.Refurbish the mechanism

2.The iron core surface has oil sticking to it

2.Remove oil stains on the iron core surface

3.Lubricant freezes in winter

3.Treat or replace lubricating oil

Maintenance measures: Clean internal parts, check the wear of motor parts (such as brush holders, slip rings), and check for any abnormal sounds during operation. Inspect and repair controls and adjust contacts as required.

The reason for the failure:Brake damage

Maintenance methods:change break

Maintenance measures:Check the working condition of the brake and replace it if there is any problem.