Mantenimiento e inspección esenciales de polipastos eléctricos de cable para un rendimiento superior

Date: 12 Sep, 2024

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Like all mechanical equipment, wire rope hoists are subject to wear, and tear, and occasional breakdowns. Recognizing the early signs of trouble and knowing how to address them can mean the difference between making minor adjustments facing costly and time-consuming repairs, or worse, a complete operational shutdown.

The importance of electric wire rope hoist maintenance and inspection cannot be overstated. It not only ensures the longevity and optimal performance of the hoist but also guarantees the safety of operators and the workplace. This article aims to equip wire rope hoist users with the knowledge needed for wire rope hoist maintenance and inspection.

Electric Wire Rope Hoist Basic Components

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Wire Rope: The wire rope is the lifeline of the crane, made from multiple strands of metal wires twisted together, providing strength and flexibility. The structure of the wire rope affects its strength, flexibility, and resistance to bending fatigue and wear.
Drum: The wire rope is wound around this cylindrical component. The drum rotates to wind or unwind the rope, facilitating the lifting or lowering of loads.
Motor: Powers the hoist by driving the drum to wind the wire rope. The motor’s specifications determine the maximum load capacity and lifting speed.
Gearbox: Connected to the motor, the gearbox reduces the motor’s speed to provide the torque needed for lifting loads. This component is crucial for maintaining control over the lifting and lowering speeds.
Rope Guide: Ensures the wire rope is evenly wound on the drum, preventing tangling and wear. Proper adjustment and maintenance of the rope guide are essential for the smooth operation of the hoist.
Hook Block: Attached to the end of the wire rope, it includes a hook for securing loads, often equipped with a safety latch to prevent the load from slipping off.
Control System: Allows the operator to control the movement of the crane. This could be a pendant controller, a wireless remote, or a cab controller in more complex systems.
Limit Switches: Safety features that prevent the hook block from over-traveling, protecting the crane and load from damage.
Brake System: Ensures that the crane can hold the load stationary when lifting power is not applied, which is crucial for operational safety.

Electric Wire Rope Hoist Maintenance

Preventive wire rope hoist maintenance is the cornerstone of ensuring the longevity and reliability of wire rope hoists. This proactive approach involves regular inspections, lubrication, timely repairs, and adherence to a wire rope hoist maintenance plan tailored to the hoist’s operational requirements and environmental conditions. It aims to prevent common issues like wire rope wear, misalignment, and mechanical failures. Proper upkeep can identify signs of wear or damage in advance, allowing for timely repairs and significantly reducing the likelihood of unexpected breakdowns and costly downtime. Here are key strategies for implementing a robust preventive wire rope hoist maintenance program.

Regular Wire Rope Hoist Inspections

Daily Inspections

Operators should perform a visual wire rope hoist inspection daily to check for any signs of wear or damage on the wire rope, hook, and other visible components. Ensure that all controls are functioning properly and that the hoist operates smoothly without any unusual noises.

Inspection Items	Requirements
Work Location	Ensure there are no obstacles within the operator’s walking area.
Running Tracks	From the ground, observe that there are no abnormalities on the tracks.
Button Controls	The lifting, lowering, and lateral movements should be responsive and accurate. Pressing a group of buttons simultaneously should not cause the hoist to operate.
Interruptores de límite	When the hook is unloaded and reaches the limit position, the limit switch should be accurate and reliable.
Hook Assembly	The hook should rotate freely within a 360° horizontal and 180° vertical range. Ensure that the pulley rotates smoothly without jamming or rubbing, the hook nut has no abnormality, and the groove lock device functions properly.
Wire Rope	Inspect visible sections of the wire rope daily for any signs of damage or deformation. Pay special attention to the points where the wire rope is secured on the machinery. Report any noticeable changes to a supervisor, who should inspect according to ISO4309:2017, section 5.2.
Frenos	The brakes for lifting, lowering, and operation should be responsive and reliable.
Guide Rollers and Other Safety Devices	Ensure that they operate normally and are safe and reliable.

ISO-4309-2017 Descargar

Regular Detailed Inspections

Schedule comprehensive wire rope hoist inspections at intervals recommended by the manufacturer, typically every six months or annually. These wire rope hoist inspections should be conducted by trained personnel who can identify signs of wear, corrosion, or damage to mechanical and electrical components.

Monthly Inspections

The frequency of monthly wire rope hoist inspections is determined based on the importance of each component for safe operation, the frequency of use, and whether the part is considered to be prone to wear. Generally, inspections are categorized into three levels:

Level I: Must be inspected monthly.
Level II: Must be inspected every three months.
Level III: Must be inspected every six months.

The wire rope hoist inspection items, requirements, and levels are outlined in the table below:

Inspection Items		Requirement	Level
Running Tracks (I-Beam)	Obstacles within Running Range	The minimum distance from buildings and other equipment should be no less than 100mm.	I
	Track End Stops and Connection Bolts or Welds	No deformation or damage; bolts should not be loose; welds should be free of cracks.	I
	Connection Bolts for Fixed Tracks	Bolts should not be loose.	III
	Track Joint Welds	Welds should be free of cracks or defects.	III
	Track Wear	No abnormal deformation or wear at the contact points with wheels.	III
Hook Assembly	Pulleys	Pulley grooves should not have abnormal wear; rims should be intact and undamaged.	I
	Appearance	Pulley covers should not be damaged; shaft covers and pins should not be loose; hook locking device should operate normally.	I
	Working Condition	Pulley rotation should be smooth and flexible.	III
Balance Pulley	Appearance	The pulley should be undamaged and connections should be secure.	III
	Wall Plates	Bolts should not be loose.	III
	Wheels	Tread and rims should not have abnormal wear or damage.	III
Wire Rope	End Fixation	Wire rope ends should be securely fixed and free from abnormalities.	I
	Appearance	No kinks, burns, significant looseness, or corrosion; rope should be lubricated.	I
	Safety Standards (Discard Criteria)	Follow ISO4309:2017 section 6.	I
Gears	Lubrication	Open gears should be regularly greased; enclosed gears should be regularly oiled.	II
Cables	Appearance	Cables should be free of external damage, abnormal bending or twisting, and aging.	II
Cables	Assembly Condition	Connections to switches should be secure; central ring should not be detached from the slide; support wires at both ends should not be loose.	III
Collector	Working Condition	Collector rollers should rotate smoothly and without noticeable wear.	II
Collector	Appearance	Connection bolts should not be loose; insulators should not be loose or damaged; springs should not have lost their elasticity.	III

Annual Inspection

Electric hoists that are in normal operation should undergo a comprehensive safety inspection once a year. The items and requirements for the annual wire rope hoist inspection are outlined in the table below:

Inspection Items		Requirement
Tracks (I-Beam)	Surface Cleanliness	No oil stains or excessive dust.
	Inclination	Should not exceed 1/1000.
	Joints	No cracks in welds or tracks; vertical and horizontal offsets should not exceed 1mm.
	Wear Condition	Wear on the surface should not exceed 10% of the original size; width wear should not exceed 5% of the original size.
Wheels	Rim	Wear on the rim thickness should not exceed 50% of the original thickness; the lateral total gap between the rim and track should be less than 50% of the wheel tread width.
	Tread	Wear on the tread diameter should be less than 5% of the original size; diameter difference should be less than 1% of the nominal diameter; roundness difference should be less than 0.8mm.
	Appearance	No cracks or damage.
Frenos		Repeat checks as per monthly inspection requirements.
Wire Rope		Repeat checks as per monthly inspection requirements.
Gears	Lifting Mechanism Gears	Wear on the first-stage gear should be less than 10% of the original tooth thickness; other gears should be less than 20%.
	Running Mechanism Gears	Wear on the first-stage gear should be less than 15% of the original tooth thickness; other gears should be less than 25%; open gears should be less than 30%.
	Tooth Surface Defects	No cracks or broken teeth; pitting damage should not exceed 30% of the mating surface, and depth should not exceed 10% of the original tooth thickness.
Gancho	Appearance	Surface should be free of cracks; no plastic deformation at threaded parts, danger sections, or neck; defects should not be repaired by welding.
	Danger Section Wear	Wear should not exceed 5% of the original size.
	Opening Degree	Should not exceed 10% of the original size.
	Twisting Deformation	Should not exceed 10.
Pulleys		Uneven wear should be less than 3mm; wall thickness wear should be less than 20% of the original wall thickness; bottom wear should be less than 25% of the wire rope diameter; no other defects that damage the wire rope.
Shafts	Gear Shaft Wear	Wear should not exceed 1% of the original shaft diameter.
Shafts	Other Shafts	Wear should not exceed 2% of the original shaft diameter.
Tambor		No cracks; wall thickness wear should be less than 10% of the original wall thickness.
Keys		Keys and keyways should not have looseness, deformation, or abnormal wear.
Splines		No abnormal wear or deformation.
Rolling Bearings		No damage or cracks.
Oil Seals		No cracks on the mating surface.
Cables		Repeat checks as per monthly inspection requirements.
Collector		Repeat checks as per monthly inspection requirements.
Insulation Resistance		Insulation resistance to ground should be no less than 1.5 MΩ.
Resistance Between Live Parts and Grounding Screws		Should not exceed 0.19 Ω.

Lubrication

Regular lubrication of the wire rope and other moving parts is crucial for minimizing friction, wear, and corrosion. Use lubricants specified by the manufacturer and apply them according to the recommended schedule.

Cuerda de alambre:

The wire rope must be kept clean and well-lubricated to maintain optimal performance.
Lubricate the wire rope every 3 months (more frequently if usage is heavy or conditions are harsh).
To lubricate the wire rope, first remove any dust, dirt, moisture, or other accumulations. Then apply lubricating oil or a similar product to the wire rope.
Ensure the lubricant covers the entire surface and length of the wire rope.
In dusty environments, it is advisable to use a dry lubricant.
For environments where lubricant loss from the wire rope is not acceptable, consider using a non-drip motorcycle chain lubricant.

Wire Rope Drums, Hook Blocks, Pulleys, Trolley Wheels, and Gears:

Lubricate these components every 3 months (more frequently if usage is heavy or conditions are harsh).
In dusty environments, use a dry lubricant.
For situations where lubricant loss from drums, hook blocks, pulleys, trolley wheels, and gears is not acceptable, consider using a non-drip motorcycle chain lubricant.

Load Testing

Conduct a load test annually or according to local regulations and manufacturer requirements. This ensures that the crane can safely handle its maximum rated load and helps identify potential issues under operational stress.

Record Keeping

Maintenance Log: Keep detailed records of all wire rope hoist inspections, maintenance activities, and repairs. This document helps track the crane’s long-term performance, making it easier to anticipate and prevent future issues.
Compliance Documents: Ensure that all maintenance and repair activities comply with local safety regulations and industry standards. Accurate record-keeping will also support warranty claims and regulatory inspections.

Training

Operator Training: Ensure that all operators receive training on the proper use of the crane, including daily inspection procedures and correct operating practices to minimize wear.
Maintenance Training: Maintenance personnel should receive specific training for the crane models they are responsible for, enabling them to perform inspections and routine maintenance effectively.

Environmental Considerations

Prevent Adverse Conditions: If the crane is used in harsh environments, such as those with high humidity, dust, or corrosive substances, increase the frequency of wire rope hoist inspections and maintenance to counteract these conditions.

cristal

Experto en OEM de grúas

Con 8 años de experiencia en la personalización de equipos de elevación, he ayudado a más de 10 000 clientes con sus preguntas e inquietudes de preventa. Si tiene alguna necesidad relacionada, no dude en ponerse en contacto conmigo.

WhatsApp: +86 199 1373 9708

Correo electrónico: krystalli@kscranegroup.com

ETIQUETAS: wire rope hoist inspection,wire rope hoist maintenance