Overhead Crane Installation & Commissioning Guide
Key Points The three critical engineering standards for overhead crane installation and commissioning are: track accuracy (span deviation ≤±3mm, rail top elevation difference ≤±5mm/10m, joint gap 1–2mm, misalignment ≤0.5mm), limit switch calibration (hoisting limit trigger point must maintain ≥2 safety wraps on the drum, crane bridge travel limit set at ≥1.5m from the rail end or 1.25× braking distance), and electrical wiring (main circuit insulation ≥1MΩ/500V, control circuit ≥0.5MΩ, grounding resistance ≤4Ω). Load test: no-load at 100%, static load at 125%, dynamic load at 110%, with staged acceptance.
The installation and commissioning of an overhead crane (bridge crane) is the most technically critical phase before the equipment enters service. Kelude Heavy Industry provides on-site installation services nationwide, with certified installation crews equipped with a full set of inspection and detection instruments. The process covers six major procedures: civil foundation acceptance, crane rail installation, main girder hoisting, electrical wiring, limit switch calibration, and load testing. The precision and workmanship of each step directly determine the equipment's service life, operational safety, and compliance with acceptance standards. This article uses the LD Type single-girder and QD Type double-girder bridge cranes as examples to systematically outline the engineering standards, construction requirements, and acceptance methods for the entire process, along with recommended tools, consumables, and solutions to common issues.
For detailed answers to frequently asked questions during installation and commissioning, refer to Overhead Crane Installation & Commissioning Q&A. For guidance on configuring the safety protection system, see Intelligent Safety Protection System Configuration Guide for Overhead Cranes.
Standardized overhead crane installation and commissioning process
Foundation Acceptance and Site Survey
Before installation begins, the factory building's crane runway girders or gantry crane foundation must be inspected and accepted. Verify that the concrete strength has reached 100% of the design value (after 28 days of standard curing), the crane runway girder span deviation is ≤±5mm, and the elevation deviation is ≤±10mm (≤±5mm between adjacent columns). Use a level instrument to measure the full-length elevation of each crane runway girder and a theodolite to measure the span. Embedded parts (anchor bolts) must have a position deviation of ≤±2mm, with bolt perpendicularity within 1/100. All acceptance data must be recorded and signed off by both parties, serving as the baseline for subsequent procedures.
Crane Rail Installation and Alignment
Rail installation is performed in accordance with ISO 12480 and FEM 1.001 standards:
| Inspection Item | Bridge Crane / Overhead Crane | Gantry Crane | Detection Tool |
|---|---|---|---|
| Span Deviation | ≤±3mm | ≤±5mm | steel coil Ruler+Spring Scale |
| Rail Top Elevation Difference | ≤±5mm/10m | ≤±5mm/10m | Level Instrument |
| Straightness | ≤1mm/m | ≤1.5mm/m | Wire Stretching Method |
| Joint Clearance | 1~2mm | 1~2mm | Feeler Gauge |
| Joint Misalignment | ≤0.5mm | ≤0.5mm | Straightedge+Feeler Gauge |
Rail clamps are arranged at the design spacing (standard ≤700mm), with buffer stops installed at both ends of each rail. Rail joints on the same span must be staggered, with adjacent joint offsets ≥500mm. Rail grounding is achieved by welding 40×4 galvanized flat steel to the rail, with weld length ≥100mm and grounding resistance ≤4Ω. P38/P43 rail welding requires preheating to 200–300°C, followed by slow cooling after welding.
Main Girder Hoisting and Assembly
Main girder hoisting is the highest-risk step in the installation process and requires a dedicated lifting plan that must be reviewed and approved. Before lifting, verify that the crane's rated load is at least 1.5 times the main girder weight, and position the lifting points based on the girder's center of gravity (typically at L/4 from each end). After the main girder is lifted to its installation height, it is connected to the end carriages using high-strength bolts (grade 10.9), tightened in two passes to the specified torque: an initial tightening to 50%–60% of the final torque, followed by final tightening to the design value (M20 bolts: approximately 400–500 N·m). The electric hoist is then mounted on the I-beam rail of the main girder, with the clearance between the travel wheels and the rail set to 1–2 mm (too tight causes binding; too loose results in sway).
Electrical Wiring and Insulation Testing
Electrical wiring is verified circuit by circuit against the design drawings, starting with the control circuits before the main circuits. The insulation resistance of the main circuits must be ≥1MΩ (measured with a 500V megohmmeter), control circuits ≥0.5MΩ, and phase-to-phase insulation on the conductor rail ≥0.5MΩ. Grounding resistance must be ≤4Ω (measured with a ground resistance tester). The grounding busbar uses 40×4 galvanized flat steel or copper-core wire of at least 16mm².
Before energizing, complete the following checks: power supply phase sequence matches motor rotation direction, terminal blocks in the control cabinet are tightened (torque per manufacturer's specifications), and all wire numbers are clearly marked. After energizing, operate in jog mode to verify that the travel directions of the crane bridge, trolley, and hoist match the markings on the operator controls (if not, adjust the VFD parameters or swap phases). Run a no-load test for at least 30 minutes, monitoring motor temperature rise (≤80K), VFD fault codes, and contactor operation sounds.
Limit Switch Calibration
Hoisting height limit switch: With an empty hook, raise at slow speed. The limit switch must trip when the top of the hook block sheave is at least 2 turns of wire rope from the drum, with an upward tolerance of ≤20mm at the trip point. The heavy hammer limit switch must swing freely, with the actuating rod perpendicularity within 5°. For the crane bridge and trolley travel limit switches: set the trip positions at both ends of the rail, with a buffer distance of ≥1.5m after tripping, or calculated as braking distance v²/(2a) × 1.25. All limit switches must undergo three repeated trip tests, with each trip position deviating no more than 10mm from the set value. The overload limiter must trigger an alarm at 110% of rated load and operate normally below 100%.
Load Testing
| Test Item | Load | Operating Requirements | Acceptance Standard |
|---|---|---|---|
| No-Load Test | 0% | Three Mechanisms Full Travel Round Trip Each3Times | None Abnormal noise, No Jamming, No Creeping, No Abnormal Vibration |
| rated load | 100% | Lifted Off Ground100mm Static Measurement Deflection | Main Girder Deflection≤L/700(A4), Braking Drop Amount≤v/100(m) |
| Static load test | 125% | Minutes4Step Loading(25%~50%~75%~100%~125%), Hold Load at Each Step5min | Hold Load at Each Step10min No Permanent After Deformation, Weld Seam No Cracking, No Abnormal Noise |
| Dynamic Load Test | 110% | Hoisting / Lifting/Lowering/Crane Bridge / Long Travel/Trolley Interlocking Operation, Repeated Operation15min | All Mechanisms Operate Normally, Braking Reliable, No Abnormal Temperature Rise |
For load testing, standard weights (Grade M1) or calibrated steel ingots are the preferred counterweights. Hydraulic jacks or hand chain hoists must never be used as substitutes for test weights during static load tests. Upon completion of the test, a formal Load Test Report is issued and submitted as a mandatory document for TSG Q7016-2016 supervision inspection.
Related Standards & References
• TSG 51-2023 Crane Safety Technical Supervision Regulation
• ISO 4301 Crane Design Standard — Key Provisions Explained: Loads, Structures, Mechanisms, Electrical Systems & Safety
Frequently Asked Questions
Q: How do I correct an out-of-tolerance runway span deviation?
A: Deviations within ±5 mm can be corrected by adjusting the rail clamp positions (each clamp provides approximately 3 mm of adjustment travel). For deviations exceeding ±5 mm, the crane runway girder must be repositioned or the foundation concrete reworked. Compensating for rail misalignment through eccentric wheel block adjustment is not recommended, as it leads to wheel rail gnawing and abnormal noise. Kelude's installation team uses laser distance sensors for runway surveys to ensure first-pass acceptance.
Q: What should I do if insulation resistance measures below 1 MΩ?
A: Use a sectional troubleshooting approach — disconnect the main power supply, measure the total resistance first, then isolate and test each branch circuit sequentially. Common causes and remedies: moisture in the motor (remove and bake in an oven at 80°C for 8 hours), water ingress in the junction box (dry thoroughly and replace the gasket), carbon buildup on the conductor rail (clean with an alcohol-dampened cloth), and damaged cable (replace or wrap with self-bonding rubber tape).
Q: How do I design a counterweight plan for a 125% rated load static load test?
A: Standard procedure: use calibrated steel ingots or concrete test blocks, each weighing no more than 50% of the rated load to allow incremental loading. Loading sequence: 25% → 50% → 75% → 100% → 125%, holding each step for 5 minutes while measuring main girder camber changes. Hold the 125% load for 10 minutes, then unload and measure residual deformation. Hydraulic jacks must not be used to simulate the load, as jack-applied forces do not meet the free-hanging condition required by the standard.
Q: Which documents must be archived after installation and commissioning?
A: The mandatory handover documentation includes: 1) Installation contract and Technical Agreement; 2) Product Certificate and Factory Acceptance Test Report (FAT); 3) Quality certificates and certificates of conformity for major purchased components (electric hoist, motor, reducer, brake); 4) Runway installation survey records (span, elevation, straightness); 5) Electrical insulation resistance test records; 6) Load Test Report (including deflection measurement data); 7) TSG Q7016 supervision inspection report (for cranes with lifting capacity ≥ 3 t); 8) Operator training records and signed handover forms. All documents must be prepared in triplicate: one set for the user's archive, one for the contractor's records, and one for the special equipment inspection authority.
