6 Harbour Portal Cranes Failure and Maintenance Manual

With the continuous expansion of the scale of construction of ports, docks, etc., the scope of application of harbour portal cranes in port operations is also increasing day by day.

To give full play to the functions of equipment and maintain the safety and reliability of operations, it is necessary to strengthen the maintenance and management of harbour portal cranes. During the daily operation of harbour portal cranes, wire rope pulleys, reducer gears, couplings, brakes, three-phase AC motors, high-voltage cabinets, transformers, etc. often fail. Effective maintenance measures need to be taken to minimize the probability of related harbour portal crane failures and keep the harbour portal cranes in good operating condition. On this basis, improve the efficiency of port operations and ensure production safety.

Harbour Portal Cranes Failure1:Wire rope pulley failure

In harbour portal cranes failure, wire rope pulleys are the main force components, and bearing damage, rim cracking, or thinning often occur during equipment operation. The root cause of the above problems is that the wire rope and the pulley are connected, and the two sides jointly produce extrusion force, and then the pulley will be affected by friction and gradually thinned. When the thinning reaches a certain extent, the pressure caused by the wire rope exceeds the pressure it can withstand and cracking problems occur.

Maintenance Manual 1

Maintenance of wire rope pulley blocks to ensure the stable and safe operation of the pulley blocks, first of all, it is strictly forbidden to overload the crane during use, so as not to increase the bearing capacity of the pulley blocks and cause bearing damage.

Secondly, the crane wire rope should be regularly lubricated and maintained to reduce the friction between the pulley and the wire rope and to avoid serious wear and tear of the pulley rim and wheel groove.

Finally, if there is serious wear and tear on the wheel groove, such as uneven wear rate of not less than 3 mm, cracks in the pulley, and the wall thickness wear value accounts for 1/5 of the original wall thickness, etc., the pulley needs to be scrapped and replaced with a new pulley.

Harbour Portal Cranes Failure 2:Reducer gear failure

In a harbour portal crane, the reducer is a basic transmission component that transmits torque during the gear meshing process and then adjusts the motor speed until it reaches the operating requirements. Gear failures, such as glued tooth surfaces, disconnected teeth, and severely worn tooth surfaces, often occur in this process.

Maintenance Manual 2

During the maintenance of the reducer gear, it is required that the crane is not overloaded during use and that it is smooth and slow during braking or start-up. It cannot be reversed directly without stopping the operation if it is not an emergency. Operation. During use, the reducer gear should be regularly supplemented with lubricating oil that meets the reducer’s operating conditions requirements, and the housing should be cleaned in time.

In addition, it is necessary to regularly inspect and analyze the oil quality of the lubricating oil, combine the inspection results to clarify the wear of the reducer gear, and take targeted maintenance measures to avoid increased wear and ultimately cause equipment accidents.

Harbour Portal Cranes Failure 3:Coupling failure

The meshing teeth of the harbour portal crane toothed coupling are prone to wear and tear, and even problems such as broken teeth and gnawing teeth may occur. If the harbour portal crane plum blossom elastomer coupling is used, the plum blossom elastomer is prone to wear, accelerated aging, or fatigue cracking during the long-term operation of the crane. In the long-term use of harbour portal cranes, the elastic ring of the elastic pin coupling will also be severely worn, and the pin is easy to lose so that the transmission noise and vibration emitted by the coupling during transmission will increase, affecting the normal operation of the equipment. In addition, the counterpart bolts of the coupling will also break and cause mechanical failure.

Maintenance Manual 3

During the long-term operation of the harbour portal crane gear coupling, the inner and outer teeth will be subject to certain wear and tear, so it is necessary to do a good job of lubrication and regular maintenance. At the same time, the elastomer coupling should be checked regularly, especially the use of elastic elements and pins. Once the elastic elements are found to be damaged, they need to be replaced in time.

During regular inspections, attention should also be paid to regular tightening of bolts to prevent loose bolts from affecting the normal operation of the equipment.

In the process of installing the coupling, the alignment must be corrected to avoid reducing the service life of the equipment due to improper combination methods.

At the same time, grease should be filled regularly to ensure that the meshing gap between the inner and outer teeth has good lubrication performance and reduces wear. Attention should be paid to the smooth and slow operation of the crane.

During the operation of the harbour portal crane coupling, regular inspections should be strengthened. In the event of abnormal conditions such as vibration or excessive abnormal noise, it is necessary to stop for inspection and maintenance in time.

Harbour Portal Cranes Failure 4:Brake failure

In actual production, the harbour portal crane brakes of in actual production, the brakes of gantry cranes often fail, including：

• The brake pads are worn abnormally, which reduces the service life of the brake pads and requires frequent replacement；
• The braking clearance exceeds a certain standard, thereby reducing the braking effect and even the inability to brake；
• It is easy to make the temperature of the brake wheel exceed a certain standard during braking, and then the elastic rubber ring of the connecting pin dissolves and ages under the influence of high-temperature factors；
• The joints of the brake arms are stuck and the brakes cannot be stretched smoothly. This kind of phenomenon will cause the lifting, loading and unloading production to face huge safety risks.
• The brake pads are worn abnormally, which reduces the service life of the brake pads and requires frequent replacement；
• The braking clearance exceeds a certain standard, thereby reducing the braking effect and even the inability to brake；
• It is easy to make the temperature of the brake wheel exceed a certain standard during braking, and then the elastic rubber ring of the connecting pin dissolves and ages under the influence of high-temperature factors；
• The joints of the brake arms are stuck and the brakes cannot be stretched smoothly. This kind of phenomenon will cause the lifting, loading and unloading production to face huge safety risks.

Maintenance Manual 4

To effectively prevent brake failure, it is necessary to check related equipment regularly and pay attention to the following 4 problems at the same time：

• The focus is on checking whether the hinge part of the pin shaft is severely worn or stuck and whether the relevant connection position is loose；
• Comprehensively inspect and scientifically verify whether the gap between the brake pads and the brake wheels is up to standard；
• Check whether the hydraulic system is in normal working condition；
• The brake pads and brake wheels should be checked for wear and tear, and the surface should be free of dirt.

Through the above inspection, the operating state maintained by the brake can be mastered. In addition, the lubrication and maintenance of each joint position of the brake should be strengthened, and the braking stroke should be adjusted appropriately under the actual situation to ensure that the brake is effective and safe.

Harbour Portal Cranes Failure 5:Three-phase AC motor failure

In harbour portal cranes, three-phase AC motors play an energy conversion role, which can convert electrical energy into mechanical energy, but they are often affected by various factors in the operation of the equipment and fail.

When the power supply voltage is too high, the excitation current will rise, causing the motor to heat up excessively. When the heating temperature exceeds a certain standard, the motor insulation will be damaged and the risk of breakdown will be increased.

If the power supply voltage is too low, the electromagnetic torque will be significantly reduced.

If the load torque is not reduced synchronously at this time, the overall rotor speed will be too low, and excessive deviation will cause motor overload problems, further increasing heat generation.

If this problem cannot be solved in time for a long time, it will be disturbed by external moisture factors, affecting the normal operation of the three-phase AC motor, and will accelerate the aging of the insulating layer and reduce the service life of the three-phase AC motor.

Maintenance Manual 5

During harbour portal crane daily maintenance and maintenance of three-phase AC motors, the power supply must be cut off in advance to maintain the safety of equipment and operators. After the operation of the motor is over, the maintenance operation should be carried out. It should be noted that some parts may have high-temperature conditions. It is necessary to cool down reasonably before performing maintenance operations to maintain the safety of personnel. If the gantry crane is in a state of shutdown for a long time, to avoid motor failure, it usually has to be operated at least once a month to ensure that the motor heater remains in normal working condition and check the motor for damage to parts in time to avoid damage at the beginning of the later motor use.

During the use of the motor, the odor, sound, and vibration amplitude and frequency in the operation of the motor should be dynamically observed. Once the smell of burning is found, it is necessary to stop work in time and strictly inspect the winding and other parts to prevent key parts from being burned.

Harbour Portal Cranes Failure 6:Abnormal noise at the hinge point of the boom

During frequent operations, because of the large impact force, harbour portal cranes often experience ageing and damage to parts, and then abnormal noises occur during luffing operations.
For example, during the operation of a harbour portal crane, the lower hinge point of the lifting arm is due to the presence of powdered or granular foreign objects, and the shaft end baffle screws are cut off or loose, which causes abnormalities and affects the normal operation of the crane, and lays certain safety risks.

Maintenance Manual 6

During the use of harbour portal cranes, to prevent abnormal noise and other failures at the lower hinge point of the boom, it is necessary to strengthen daily inspections, tighten the shaft end baffle screws in time and clean up foreign objects.

If harbour portal crane has been an abnormal noise, the force calculation and analysis can be performed first, and then the rolling bearing can be replaced. During the period, it should be noted:

• First keep the crane amplitude at a balance point of about 25 m, and the live counterweight of the boom system is passed through 2 wire ropes (Φ32 mm), which are closely connected with the lifting hole behind the herringbone frame by means of a chain hoist, and the pressure of the boom and the hinge shaft is adjusted; 
• In front of the lower corner of the boom, the steel plate (20 mm) is welded to the support, and the steel plate and vertical ribs are welded at the lower corner of the boom facing up about 60 mm to maintain a relative relationship with the support; Place a 25 t jack above the process support for support .

Kwa muhtasari

In the process of cargo loading and unloading at ports and terminals, harbour portal cranes play an important role, but their operating environment has high air humidity and dust, and they are often affected by external environmental factors and fail. Coupled with the irregular operation of the staff, the equipment will be seriously damaged. Therefore, the equipment management party should comprehensively analyze the common failures of harbour portal cranes during use, formulate targeted maintenance plans, take effective maintenance and maintenance measures, and check the operating status of equipment components on time to reduce the probability of equipment failures and ensure safe, efficient and reliable operation of equipment.

Cindy

WhatsApp: +86-19137386654

Barua pepe: cindywang@hndfcrane.com

Mimi ni Cindy, nina uzoefu wa miaka 10 katika tasnia ya kreni na nimekusanya maarifa mengi ya kitaaluma. Nimechagua korongo za kuridhisha kwa wateja 500+. Ikiwa una mahitaji yoyote au maswali kuhusu cranes, tafadhali jisikie huru kuwasiliana nami, nitatumia ujuzi wangu na uzoefu wa vitendo kukusaidia kutatua tatizo!