Assembling and detecting integrated method of electric cabinet for double-electric-frequency ship

Abstract

The invention discloses an assembling and detecting integrated method for a double-electric-frequency marine electric cabinet, and relates to the technical field of marine electric equipment. According to the method, five modules including adaptation preprocessing, independent assembly, standard wiring, graded detection and customized packaging are sequentially and cooperatively operated, the whole process of assembly and detection of the marine electric cabinet is comprehensively covered, core operation requirements and adaptation standards of all the modules are defined, and through detail optimization and performance enhancement, the assembly and detection efficiency of the marine electric cabinet is improved. The anti-vibration, anti-corrosion and anti-interference performance and the operation stability of the electric cabinet are synchronously improved, the double-electric-frequency switching response is rapid, the impedance index reaches the standard, and the high-reliability use requirement of a ship in a complex environment is completely met.

Description

Technical Field

[0001] This invention relates to the field of electrical equipment assembly and testing technology, and in particular to an integrated method for the assembly and testing of a dual-frequency marine electrical cabinet. Background Technology

[0002] Dual-frequency marine electrical cabinets are the core control unit of a ship's power system, playing a crucial role in providing stable frequency conversion power to the ship's propulsion equipment and auxiliary devices. Their assembly quality and operational reliability directly affect the ship's navigation safety. The ship's navigation environment is unique, constantly facing severe vibrations, salt spray corrosion, high humidity, and complex electromagnetic interference, and with limited installation space, stringent requirements are placed on the electrical cabinet's environmental adaptability, anti-interference capabilities, and structural stability. Existing technologies for dual-frequency marine electrical cabinets suffer from numerous defects: components lack marine-grade specific compatibility, and the cabinet's anti-corrosion and sealing treatment is inadequate; the installation of dual-frequency modules lacks clear isolation distances and seismic fixing standards, easily leading to mutual interference; wiring processes lack unified specifications, with strong and weak current crossings causing severe electromagnetic interference, and wiring is prone to loosening due to vibration; testing procedures lack specific parameter standards, especially impedance-related testing data is unclear, and there are no unified requirements for dual-frequency module switching response time and voltage fluctuation control; the packaging method is simple, making the equipment susceptible to damage during transportation due to vibration and moisture.

[0003] Therefore, those skilled in the art provide an integrated assembly and testing method for dual-frequency marine electrical cabinets to solve the problems mentioned in the background art. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing an integrated assembly and testing method for dual-frequency marine electrical cabinets. Through the coordinated operation of five major modules, it simultaneously achieves standardized assembly, reliable performance, and safe transportation, fully meeting the usage requirements in complex marine environments.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: An integrated assembly and testing method for dual-frequency marine electrical cabinets includes: Adaptation to preprocessing module: This module ensures the marine compatibility of electrical cabinets and components from the outset. Key operations include verifying the electrical cabinet's dimensions, opening locations, and surface anti-corrosion coating to ensure precise matching with the ship's mounting base and avoid installation deviations; checking the marine-grade certifications of components such as dual-frequency modules and transformers to ensure they possess the core marine performance characteristics of vibration and moisture resistance, and are free from damage or deformation; scraping off paint and applying marine-grade anti-rust grease to the bolted connections of the cabinet to enhance their resistance to salt spray corrosion and prevent loosening due to corrosion during long-term use; and retaining all component accessories and instruction manuals to provide complete technical support for later installation, commissioning, and maintenance, thus mitigating various malfunctions caused by incompatibility from the outset.

[0006] Independent assembly modules: This module adopts an isolated, shock-resistant assembly design. Marine-grade flame-retardant cable trays and guide rails are installed, with flexible two-point or three-point fixing methods depending on the guide rail length (two-point fixing for lengths ≤50cm, three-point fixing for lengths >50cm), ensuring stable installation and providing a stable mounting foundation for components. The dual frequency modules are installed in isolated areas on the left and right sides of the cabinet, with a minimum spacing of 15cm and ample space for heat dissipation, effectively preventing electromagnetic interference and heat accumulation between modules. The transformer is secured with anti-loosening screws, and the braking resistor box is installed in a dedicated position on the right side panel. The touchscreen and protective cover are installed by two operators to ensure installation accuracy. Simultaneously, a shock-absorbing bracket is added to the bottom of the dual frequency modules, with compression controlled at 5-8mm. Combined with anti-vibration rubber pads at both ends of the guide rails, this effectively buffers the impact of ship vibrations on components. Marine-grade explosion-proof cooling fans are installed within the heat dissipation channels, with fan start / stop linked to the operating status of the dual frequency modules, ensuring the modules remain within a safe temperature range and significantly improving the cabinet's shock resistance and heat dissipation stability.

[0007] Standardized cabling module: This module adheres to the principles of "anti-interference, vibration prevention, corrosion resistance, and easy maintenance," selecting marine-grade flame-retardant, oil-resistant, and salt-spray-resistant cables to ensure the weather resistance and service life of the wiring. A multi-level grounding system is constructed using yellow-green dual-color grounding wires, with reliable connection between the cabinet grounding busbar and the ship's grounding system to ensure grounding safety and reduce the risk of leakage. Strong and weak current wiring is separated to avoid cross-interference, and a 15-20cm allowance is reserved for wiring inside the cabinet door to prevent pulling on the wiring when opening and closing the door. All wires are equipped with number tubes in the same direction, and communication lines are secured with vibration-damping cable ties at intervals not exceeding 20cm, improving wiring neatness and facilitating future maintenance. Terminal blocks are strictly matched to wire specifications, and dual-frequency modules and transformers are equipped with dedicated terminals. PLC signal sampling lines use shielded cables with both ends of the shield grounded, further enhancing the line's anti-interference capability and ensuring stable signal transmission and power supply.

[0008] Graded detection module: This module undergoes a comprehensive three-tier testing system to verify the cabinet's performance. Internal testing includes component label verification, wiring tightness checks, grounding system verification, gland seal checks, short-circuit troubleshooting, and power-on testing to ensure assembly quality and basic functionality meet standards. Marine-specific testing includes vibration testing, salt spray testing, and electromagnetic compatibility testing to specifically verify the cabinet's adaptability to the complex marine environment. IEC standard five tests (voltage drop test, continuity test, insulation test, discharge test, and withstand voltage test) and dual-frequency module collaborative switching tests precisely control electrical performance and core functional reliability. The dual-frequency module supports both manual and automatic switching modes, with manual switching response time ≤0.5s and automatic switching response time ≤0.3s. Voltage fluctuation during switching is ≤±5%, fully meeting the continuous operation requirements of marine power systems. All tests are meticulously recorded and standardized reports are generated to ensure product traceability and verification, guaranteeing 100% product qualification upon leaving the factory.

[0009] Custom-packaged modules: This module is designed with the characteristics of ship equipment transportation in mind, employing a multi-layered protective design. First, the electrical cabinet is wrapped in moisture-proof bubble wrap and shock-absorbing stretch film, forming a basic protection against shock and moisture. Differentiated solutions are used based on the transportation distance: dedicated shock-resistant vehicles are used for short-distance transport, while reinforced wooden crates filled with cushioning materials are used for long-distance transport to effectively absorb vibrations and impacts during transportation and prevent equipment damage. Marine equipment transportation markings and warning labels for moisture resistance, shock resistance, and prohibition of inversion are affixed to the exterior to remind transport personnel to operate the equipment correctly. Upon shipment, a certificate of conformity, test report, component manuals, and assembly drawings are delivered with the product to ensure users have complete technical information, facilitating later installation, commissioning, and maintenance, and comprehensively guaranteeing the safety and standardization of product transportation from factory to delivery.

[0010] Compared with the prior art, the beneficial effects of the present invention are: 1. High degree of standardization: The five modules fully cover the entire assembly and testing process, with clear operation requirements and parameters, strong assembly consistency, good operability, and easy mass production; 2. Excellent environmental adaptability: Targeted anti-corrosion, anti-vibration, and anti-interference design enables the electrical cabinet to withstand ship vibration, salt spray, humidity, and electromagnetic interference, reducing the failure rate by more than 95%. 3. High operational reliability: The dual-frequency modules are isolated and have independent heat dissipation, resulting in rapid switching response, small voltage fluctuations, and compliance with core electrical indicators such as impedance, ensuring stable operation of the ship's power system; 4. High ease of maintenance: Standardized wiring labels, complete test reports and delivery documents greatly reduce the difficulty and cost of later maintenance. Attached Figure Description

[0011] To illustrate the technical solutions in the embodiments of the present invention or the prior art more specifically and intuitively, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0012] Figure 1 This is a flowchart illustrating the collaborative process of the five modules proposed in this invention. Figure 2 This is a schematic diagram of the graded detection module proposed in this invention. Detailed Implementation

[0013] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0014] Reference Figure 1-2 An integrated assembly and testing method for dual-frequency marine electrical cabinets, the specific implementation steps of which are as follows: Step 1: Adaptation Preprocessing 1. Select electrical cabinets that meet marine standards, verify their compatibility with the ship's mounting base, ensure that the opening position deviation is ≤±2mm, and that the surface surface has a marine-grade double-layer anti-corrosion coating thickness of not less than 80μm, and that there is no peeling or flaking after salt spray pretreatment test; the bottom gland should be a marine-specific waterproof and sealed type with an IP54 or higher protection rating, and the mounting hole position should match the marine cable specifications, with a hole diameter deviation of ≤±1mm.

[0015] 2. Select dual-frequency modules, transformers, relays, and other components with CCS or ABS marine-grade certification. Check that the appearance is undamaged and undeformed, the pins are free of oxidation, and the initial performance is normal after power-on testing. Core components must meet the requirements of vibration resistance (frequency 10-150Hz, acceleration 5g) and moisture resistance (relative humidity 95%±3%).

[0016] 3. Scrape off the paint from the bolted connections of the cabinet to expose the metal contact surfaces, apply marine lithium-based rust-preventive grease, and then tighten with lock nuts. The bolt torque should be controlled at 25-30 N·m.

[0017] 4. Organize and store the components, accessories, instruction manuals, and marine certification certificates, and deliver them with the product upon shipment.

[0018] Step 2: Independent Assembly 1. Install marine flame-retardant PVC cable trays, arranged horizontally and vertically, with smooth, burr-free cut surfaces after grinding. Use stainless steel screws for fastening, with uniform spacing and not exceeding 50mm. Cut the guide rails, using two-point fixing when the length is ≤50cm, with a fixing point spacing of ≤30cm. Use three-point fixing when the length is >50cm, with the two fixing points ≤10cm from the end of the guide rail and the middle fixing point located at the midpoint of the guide rail. Add 5mm thick anti-vibration rubber pads to both ends of the guide rail.

[0019] 2. Install the dual frequency modules in the independent areas on the left and right sides of the cabinet, with a module spacing of 15cm and a module-to-cabinet side panel spacing of 10cm, leaving sufficient space for heat dissipation; keep the modules horizontal and vertical during installation, hang the mounting screws on the upper part of the mounting holes, and tighten them with spring clips, flat washers and anti-loosening nuts, with the bolt torque controlled at 15-20 N·m; add marine rubber shock-absorbing brackets to the bottom of the modules, with the compression of the shock-absorbing brackets controlled at 5-8mm.

[0020] 3. Install a marine explosion-proof cooling fan in the heat dissipation channel. The fan has a rated voltage of 220V and a power of 30W. It is linked to the operation status of the dual-frequency module and will automatically start when the module temperature exceeds 60℃ and automatically stop when the temperature is below 40℃.

[0021] 4. The transformer is fixed to the bottom of the cabinet with four stainless steel anti-loosening screws. The screws are symmetrically distributed with a spacing of ≤20cm and the bolt torque is controlled at 20-25N·m. The braking resistor box is installed in a dedicated mounting position on the right side panel of the cabinet, isolated from the heat dissipation channel of the dual frequency module. Two operators work together to install the touch screen and protective cover. First, fix the protective cover frame, then embed the touch screen, and evenly tighten the 6 fixing screws around the perimeter. The torque of each screw is controlled at 8-10N·m. The two ends of the rail-type components are fixed with fixed terminals and anti-vibration loosening buckles are installed. The buckle clamping force is ≥5N.

[0022] Step 3: Standardize cabling 1. Marine flame-retardant, oil-resistant, and salt spray-resistant cables are selected, conforming to GB / T9330 standards. The conductor is oxygen-free copper, the insulation layer is cross-linked polyethylene, and the sheath is polyvinyl chloride. The PLC signal sampling line adopts shielded RV cable with a shielding coverage of ≥90% and grounding at both ends of the shielding layer.

[0023] 2. Construct a multi-level grounding architecture. A dedicated copper grounding busbar (thickness ≥ 5mm, width ≥ 30mm) is installed inside the cabinet. Equipment such as CPU, transformer, and power socket are connected to the grounding busbar through a 1.5 square millimeter bicolor grounding wire. The dual-frequency module is connected to the grounding busbar through a 3 square millimeter grounding wire. The cabinet doors are bridged with 2.5 square millimeter bicolor grounding wires. The grounding busbar is reliably connected to the ship's grounding system through a marine-grade grounding terminal. The paint on the grounding bolts is scraped off, and flat spring washers and anti-loosening nuts are installed. The grounding resistance is tested to be ≤ 0.05Ω.

[0024] 3. Strong and weak current wiring must be strictly separated. Strong current wiring should be routed through the left-side cable tray, and weak current wiring through the right-side cable tray. A 3mm thick metal partition should be installed between the cable trays. All wires should be equipped with wear-resistant and high-temperature resistant polyolefin tubing with the identification format of "component number + terminal number" and the direction should be uniformly "from bottom to top". A 18cm allowance should be reserved for wiring in cabinet doors, and an elastic protective sleeve should be used. The inner diameter of the sleeve should be ≥ 1.5 times the outer diameter of the wire. Communication lines should be fixed with marine-grade anti-vibration nylon cable ties at 20cm intervals.

[0025] 4. Marine-grade corrosion-resistant brass terminals are used with tin plating. The terminals are strictly matched with the wire specifications: 1.5 square millimeter wires correspond to 1.5 square millimeter terminals, and 2.5 square millimeter wires correspond to 2.5 square millimeter terminals. When two wires are connected in parallel, marine-grade parallel terminals are used, and the number of parallel wires shall not exceed three. Dual frequency modules, transformers, grounding bars, etc. are equipped with O-type marine-grade terminals.

[0026] Step 4: Grading and Testing 1. Internal Testing: Verify the consistency of component labels, ensuring no mislabeling or omissions; gently pry terminals with a screwdriver to check wiring tightness, ensuring no loosening or detachment; verify grounding system connection specifications, ensuring no crossovers; check gland seals for reliability, ensuring no loosening; use a multimeter in resistance mode to test point by point, checking for short circuits between phases and ground, and between phases; perform graded power-on tests, ensuring components and modules operate normally independently; conduct dual-frequency module collaborative switching tests, with manual switching response time of 0.4s, automatic switching response time of 0.25s, and voltage fluctuation of ±3%.

[0027] 2. Marine-specific tests: Vibration test (frequency 10-150Hz, acceleration 5g, duration 60min) was conducted according to IEC60945 Class 3 standard. No components were loose or wiring was disconnected after the test. Salt spray test (neutral salt spray, concentration 5% NaCl, temperature 35℃, duration 48h) was conducted according to ASTMB117 standard. No peeling or flaking of the cabinet coating and no corrosion of components were observed. Electromagnetic compatibility test was conducted according to IEC61000-6-2 standard. Radiated disturbance was ≤30dBμV / m, and electrostatic discharge immunity was ±8kV.

[0028] 3. IEC standard five tests and impedance-related tests: (1) Voltage drop test: threshold 1.0V, test time 10s, PE-frame voltage drop 0.07V, PE-mounting plate 0.05V, PE-door 0.10V, all meet the requirements; (2) Continuity test (impedance related): resistance threshold 0.10Ω, test time 10s, PE-frame continuity resistance 0.011Ω, PE-mounting plate 0.008Ω, PE-door 0.010Ω, all meet the standard; (3) Insulation test (impedance related): Test voltage 500V, resistance threshold 1MΩ, insulation resistance of L1-L2 28.99MΩ, L1-L3 29.99MΩ, L2-L3 24.99MΩ, L1-PE 74.99MΩ, L2-PE 69.99MΩ, L3-PE ≥19.99MΩ, N-PE 21.99MΩ, all of which meet the standards; (4) Discharge test: voltage threshold 60V, time threshold 5s, discharge time of L1-PE 3.5s, L2-PE 3.4s, L3-PE 3.2s; (5) Withstand voltage test: voltage 2500V, leakage current ≤10mA, test time 10s, no breakdown or flashover phenomenon.

[0029] 4. Inspection Records: All inspection items are recorded in detail to form a standardized marine inspection report, which includes information such as the container number, inspection date, test parameters, test results, and the signature of the inspector.

[0030] Step 5: Custom Packaging 1. Qualified electrical cabinets should first be fully wrapped in 5mm thick moisture-proof bubble bags, and then tightly wrapped with 3 layers of shockproof wrapping film; additional 20mm thick foam buffer blocks should be installed on precision components such as dual frequency modules and touch screens inside the cabinet.

[0031] 2. For short-distance (≤500km) transportation, dedicated shockproof vehicles are used, with 10mm thick shockproof rubber pads laid inside the cargo box, and the electrical cabinet is fixed inside the cargo box with steel straps; for long-distance (>500km) transportation, reinforced wooden crates are used. The wooden crates are made of multi-layer plywood with a thickness of ≥15mm, and are filled with pearl cotton cushioning material. A 5-10cm buffer space is reserved between the electrical cabinet and the wooden crate. The wooden crate is reinforced with steel straps with a spacing of ≤30cm.

[0032] 3. The exterior of the wooden crate shall be affixed with special markings for marine equipment transportation, as well as warning labels for moisture protection, shock resistance, and prohibition of inversion; when shipped, the product shall be accompanied by a certificate of conformity, various test reports, component manuals and marine certification certificates, assembly drawings, maintenance manuals, etc., all of which shall be bound into a booklet and sealed in a waterproof document bag.

[0033] Working principle: This invention controls the marine compatibility of the electrical cabinet and components from the source through an adaptation preprocessing module, laying the foundation for subsequent assembly; the independent assembly module enables isolated and shock-resistant installation of the dual-frequency module and other components, avoiding mutual interference and vibration damage; the standardized wiring module constructs a stable and interference-resistant wiring system, ensuring reliable signal and power supply; the graded testing module comprehensively verifies product performance through multi-dimensional testing (including key impedance indicators and dual-frequency switching performance), ensuring qualification; and the customized packaging module ensures that the product is not damaged during transportation. The five modules form a complete closed loop, ultimately achieving stable, safe, and continuous operation of the dual-frequency marine electrical cabinet in the complex environment of a ship.

[0034] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for assembling and testing an integrated marine electric cabinet of dual electric frequency, characterized in that, It comprises five modules which are operated in sequence, and each module has the following features: (1) Adaptation and pretreatment module: used for checking and pretreating the marine environment adaptability of electrical cabinet and double-frequency module, transformer and other components to meet the basic requirements of ship use; (2) Independent assembly module: used for realizing isolated and shock-resistant installation of double-frequency module and other components to ensure independent operation of each module without interference; (3) Standard wiring module: used for completing cable selection, grounding connection and wiring arrangement to improve the anti-interference, anti-vibration and corrosion resistance of the line; (4) Grading detection module: used for verifying the electrical performance, marine environment adaptability and safety reliability of the electrical cabinet through multi-level detection to ensure product qualification; (5) Customized packaging module: used for shockproof, moistureproof and corrosion-resistant packaging of qualified electrical cabinet to protect the product from damage during transportation.

2. The method according to claim 1, wherein, The adaptation and pretreatment module includes checking the external dimensions, opening position and surface coating of the electrical cabinet, checking the marine level certification qualification of components, checking the appearance of components without damage and deformation, scraping the paint on the bolt connection part of the cabinet body and applying marine anti-rust grease, and retaining the factory accessories and instruction manual of components.

3. The method according to claim 1, wherein, The independent assembly module includes installing marine flame-retardant wire slot and guide rail, using two-point fixation when the length of guide rail is less than or equal to 50 cm, using three-point fixation when the length of guide rail is greater than 50 cm, installing double-frequency module in the left and right isolated areas of the cabinet body, ensuring the distance between modules is not less than 15 cm and reserving space for heat dissipation, fixing the transformer by anti-loose screws, installing the braking resistor box on the right side plate, and installing the touch screen and protective cover by two operators.

4. The method according to claim 1, wherein, The independent assembly module further includes adding shock-absorbing supports at the bottom of the double-frequency module, controlling the compression amount of the shock-absorbing supports within 5-8 mm, adding marine explosion-proof cooling fans in the heat dissipation channel, linking the start and stop of the fans with the operating state of the double-frequency module, and fixing the guide rail components at both ends by fixed terminals and adding anti-vibration buckles.

5. The method of claim 1, wherein the method further comprises: The standard wiring module includes selecting marine flame-retardant, oil-resistant and salt mist-resistant cables, constructing a multi-level grounding system by using yellow and green double-color grounding wires, reliably connecting the cabinet grounding bar with the ship grounding system, separating the strong and weak current lines to avoid cross interference, and reserving a 15-20 cm margin for the wiring of the cabinet door.

6. The method of claim 1, wherein the method further comprises: The standard wiring module further includes configuring number tubes with a unified direction for all wires, fixing communication lines by anti-vibration straps with a fixed interval not exceeding 20 cm, matching the wiring terminals with the wire specifications, providing special terminals for the double-frequency module and the transformer, and using shielded cables for PLC signal sampling lines with the shielding layer grounded at both ends.

7. The method according to claim 1, wherein, The grading detection module includes internal detection, which covers component label checking, wiring tightness checking, grounding system verification, gland seal checking, short circuit checking and power-on testing.

8. The method according to claim 1, wherein, The grading detection module further includes marine special testing, IEC standard five-item testing and double-frequency module cooperative switching testing. The marine special testing includes vibration testing, salt mist testing and electromagnetic compatibility testing. The IEC standard five-item testing includes voltage drop testing, continuity testing, insulation testing, discharge testing and voltage resistance testing. All testing data are recorded and standardized reports are formed.

9. The method of claim 1, wherein the method further comprises: The customized packaging module comprises wrapping the electric cabinet with a moisture-proof bubble bag and a shockproof wrapping film, using a special shockproof vehicle for short-distance transportation, using a reinforced wooden box for packaging and filling with a buffer material for long-distance transportation, so as to ensure shockproof and moistureproof during transportation.

10. The method of claim 1, wherein the method further comprises: The customized packaging module further comprises pasting a marine equipment transportation identification and moistureproof, shockproof and anti-inversion warning labels on the outside, and delivering a certificate of quality, a detection report, a component specification and an assembly drawing and other documents with the product when the product is shipped.

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