ingiant technology | Industry new | April 19.2025
In the steel torrent of modern industry, cranes are like tireless mechanical arms, shouldering the heavy task of material handling. As the "nerve hub" of this huge machine, the performance of cable drum slip rings is directly related to the operating efficiency and safety of the crane. Faced with a wide range of slip ring products on the market, how to choose the appropriate "golden partner" for the crane? Through this article, we will help you answer the questions in your mind.
Ⅰ. Explain the working characteristics of cranes and determine the direction of adaptation
There are many members in the crane family, and gantry cranes, bridge cranes, and tower cranes each have their own "specialties". Gantry cranes are like "steel giants" in the operation scenes of port terminals and large logistics warehouses, shuttling between containers and cargoes every day. They not only have to deal with heavy loads of frequent take-off and landing, but also have to resist the erosion of salt spray and dust carried by sea breeze, as well as the "baptism" of sudden rainstorms; tower cranes are the "Optimus Prime" on the construction site. As the floors continue to rise, they need to frequently perform lifting, rotation and luffing operations, and each rotation is accompanied by severe vibration and impact. These unique working characteristics determine that they have completely different requirements for the protection level, load-bearing capacity and durability of the cable drum slip ring. Therefore, before selecting a slip ring, a comprehensive and detailed investigation of the crane's working environment, operating frequency, and load conditions is like drawing an accurate "navigation map" for subsequent selections.
Ⅱ. Focus on electrical parameters and keep a good current and voltage safety
(I) Current parameters
Current carrying capacity is the core electrical indicator of the slip ring. Generally, for small electric hoist cranes, the rated current of 50-100A can meet the basic operation requirements; while for large port gantry cranes, due to the large total power of the lifting motor, trolley running motor, and trolley running motor, the required slip ring rated current is usually 200-630A. If the actual working current of the slip ring exceeds the rated value for a long time, the heating of the conductive parts will increase. For example, for copper brushes, when the temperature exceeds 80℃, its conductivity decreases, the contact resistance increases, and electric sparks may be caused, accelerating the wear of the brushes and conductive rings.
(II) Voltage parameters
The common power supply voltages for cranes are 380V, 400V, 690V, etc. In the industrial power grid environment, the voltage fluctuates within a range of ±10%, so the slip ring needs to have a wide voltage adaptability. For example, cranes used in the metallurgical industry have large harmonic interference in the working environment. It is necessary to select a slip ring with a rated voltage of 690V and surge protection function, which can withstand an instantaneous 1.2 times rated voltage shock to ensure stable power transmission.
(III) Insulation resistance and withstand voltage
Insulation resistance reflects the electrical insulation performance of the slip ring, which is generally required to be above 500MΩ; the withstand voltage test must meet the power frequency voltage of 1500V, and there must be no breakdown or flashover for 1 minute to ensure the safe operation of the slip ring in a complex electrical environment.
Ⅲ. Combination of slip ring and cable specifications
The relationship between the cable reel slip ring and the cable is like "gear and chain". Only with close cooperation can efficient operation be achieved. When selecting a slip ring, the outer diameter of the cable, the number of cores and the material are the primary considerations. The aperture of the slip ring needs to be 1-2mm larger than the outer diameter of the cable to ensure smooth cable installation; the number of channels is determined according to the number of cable cores, and generally 1-2 spare channels are reserved.
For multi-core control cables, if the core cross-sectional area is 0.75-2.5mm², the slip ring contact resistance should be controlled within 50mΩ to ensure that the signal transmission is not distorted. Taking YC heavy-duty rubber-sheathed cable as an example, it is often used for crane motor connection. Its bending radius is generally 6-8 times the outer diameter of the cable. Therefore, it needs to be matched with a slip ring with a highly flexible brush. The brush contact pressure is maintained at 0.15-0.25N/cm² to reduce the wear between the cable and the slip ring.
Ⅳ. Strengthen the protection level and improve environmental adaptability
The working environment of cranes is often full of challenges, and high temperature, low temperature, humidity, dust, corrosive gas invasion and other situations are common. These harsh environmental factors, like "invisible enemies", always threaten the performance and life of cable drum slip rings. Therefore, choosing a slip ring with a suitable protection level according to the actual working environment is like putting on a solid "protective armor" for the slip ring.
At outdoor docks with howling sea breezes and waves, it is necessary to choose a slip ring with a protection level of IP67, which can completely prevent dust from entering and can be immersed in 1 meter deep water for 30 minutes without water ingress; in hot steel mills and foundries, the temperature in the workshop can reach above 60℃, and high-temperature resistant slip rings should be selected, whose operating temperature range is -40℃-120℃, and silicone rubber sealing materials are used, which have excellent aging resistance.
V. In-depth evaluation of mechanical properties to ensure stable operation
(I) Speed and torque
When the crane is running, the speed range of the slip ring varies greatly. The speed of the slip ring of a bridge crane is generally 10-30r/min; the speed of the slip ring driven by the slewing mechanism of a tower crane can reach 50-80r/min. When selecting a slip ring, its rated speed must be 20% higher than the actual operating speed to ensure a safety margin. At the same time, the starting torque must be considered. Generally, the starting torque of the slip ring is required to be no more than 1.5 times the rated torque to avoid damage to the internal structure due to excessive torque at the moment of starting.
(II) Mechanical life and wear resistance
The mechanical life of the slip ring is measured by the number of rotations, and high-quality products can reach 50 million to 100 million times. Its internal bearings use high-precision deep groove ball bearings with a rated dynamic load of 10-50kN; the brush material is mostly made of carbon-graphite alloy, and its hardness is controlled at 40-60HA Shore hardness to ensure good wear resistance and reduce maintenance cycles.
(III) Vibration and shock parameters
At construction sites, the vibration acceleration generated by tower cranes during operation can reach 5 - 10m/s², and the shock acceleration can reach 50 - 100m/s². Slip rings must pass vibration tests (frequency 10 - 500Hz, amplitude 0.75mm) and shock tests (half-sine wave, peak acceleration 50g, duration 11ms) to ensure stable operation under harsh working conditions.
Ⅵ. Choose a slip ring manufacturer with high-quality brands and after-sales service capabilities
In the market ocean of cable reel slip rings, product quality varies. Choosing a reliable brand is like finding a bright lighthouse in the vast ocean. Ingiant Technology has a good reputation, rich experience and professional technical strength in the cable reel DHK038 series slip ring industry, and often has strict production standards and a complete quality control system. From the procurement of raw materials to the control of production processes, to the factory inspection of products, every link is refined to ensure that every slip ring can meet high quality requirements. The perfect after-sales guarantee service is a "reassurance" that ingiant provides to users. During the use of the slip ring, once a fault occurs, the professional after-sales team can respond quickly and provide technical support and services in a timely manner, just like "timely rain", minimizing the downtime of the equipment and reducing the economic losses caused to the enterprise by equipment failure.
VII. FAQ
Q1.What causes sparks in slip rings?
A1. Poor contact: The brush is severely worn, and the contact area with the conductive ring is reduced, resulting in increased contact resistance and sparks. At this time, new brushes need to be replaced to ensure that the fit between the brush and the conductive ring is more than 80%.
Current overload: The actual working current exceeds the rated current of the slip ring, causing the conductive parts to heat up and sparks to occur. The current needs to be recalculated and the slip ring of appropriate specifications needs to be selected.
Environmental factors: In dusty and humid environments, the surface of the conductive ring is contaminated, affecting electrical contact. The slip ring should be cleaned regularly to keep it clean and dry.
Q2: How to determine whether the slip ring needs maintenance?
A2: Operating noise: If the slip ring makes an abnormal and harsh noise during operation, it may be due to bearing wear or loose internal components, and the machine needs to be stopped for inspection.
Abnormal temperature: When the surface temperature of the slip ring exceeds 70℃, it indicates that there may be poor heat dissipation or excessive contact resistance, which needs to be checked in time.
Abnormal signal transmission: If the control signal is delayed or lost, or the power transmission is unstable, it is necessary to check whether the electrical connection of the slip ring is normal.
Q3:How to choose slip rings of different materials?
A3: Aluminum alloy slip ring: light weight, good heat dissipation, suitable for small cranes with weight requirements, but relatively weak corrosion resistance.
Stainless steel slip ring: has excellent corrosion resistance and strength, suitable for use in humid and corrosive environments, such as cranes in ports and chemical industries.
Engineering plastic slip ring: good insulation performance and low cost, often used for control signal transmission of cranes with high electrical insulation requirements and small loads.
In summary, the selection of cable drum slip rings for cranes requires a "precision engineering" that comprehensively considers working characteristics, electrical parameters, cable adaptation, environmental protection, mechanical properties, product after-sales and other factors. Only after comprehensive and detailed analysis and evaluation can the most suitable slip rings be selected for the crane, so that this industrial "giant" can be more powerful in operation, operate efficiently, stably and safely, and inject continuous power into industrial production.
Post time: Apr-19-2025