Double Girder Underhung Crane 3 Ton S19m H7m M5

A double girder underhung crane is chosen over a single girder when the following benefits matter:

• Higher rigidity: Two girders resist bending better than one, especially at wide spans like 19m
• Larger hook lift: The crab trolley runs on top of the two girders, so the hook can be raised closer to the bridge — maximizing the 7m lifting height
• Better stability: The crab trolley runs on two rails (1.4m gauge), reducing load swing compared to a single-rail trolley
• Higher duty capability: Double girder cranes handle more cycles per hour at M5 duty than single girder cranes at the same capacity
• Wide span suitability: At 19m span, the double girder design provides the rigidity needed to prevent excessive deflection
• Easier maintenance: The crab design allows easier inspection and servicing of the hoist, motor, and brake

The trade-off is higher initial cost and a slightly taller crane profile — but for wide spans and higher duty, the double girder design is usually the right choice.

A crab trolley is a hoisting mechanism that runs on top of the two girders (rather than hanging below a single girder). Key features:

• Frame design: The crab has a welded steel frame that carries the hoist motor, brake, drum, and rope guide
• Two-rail travel: The crab runs on two parallel rails (1.4m gauge in this model) along the top of the two girders
• Hook lift advantage: Because the crab sits on top of the girders, the hook can be raised closer to the bridge — maximizing the usable lifting height
• Better stability: Two-rail travel reduces load swing and provides more stable trolley travel than a single-rail trolley
• Higher capacity: The crab frame distributes load across both girders, allowing higher capacities than a single girder trolley
• Maintenance access: The crab is easier to inspect and service because the hoist is on top, not underneath

The crab trolley is the standard hoisting mechanism for double girder underhung cranes and is essential for the 3t capacity and 19m span of this model.

On this double girder underhung crane, only the hoisting motion uses variable frequency drive (0.8~5.0 m/min), while trolley travel (2.0~20.0 m/min) and long travel (2.0~20.0 m/min) use dual-speed control. This is chosen because:

• Hoisting precision matters most: The VFD on the hoist gives smooth acceleration and deceleration for precise load placement — protecting the load and the crane
• Travel speeds are already sufficient: Dual-speed trolley and travel (2.0 and 20.0 m/min) provide adequate control for most workshop handling
• Cost efficiency: Hoist VFD alone is more economical than full VFD across all motions
• Proven reliability: Dual-speed travel motors with contactor control are simple, reliable, and easy to maintain
• Standard configuration for wide-bay cranes: Many wide-bay double girder underhung cranes use hoist VFD only, as the travel speeds are low enough that VFD is not essential for travel precision

If your workshop needs full VFD on all motions (e.g., for very delicate loads or anti-sway requirements), it can be specified — contact Yuantai for a full VFD double girder underhung crane.

Eight numbers on this double girder underhung crane drawing must match your workshop, or the crane will not fit or operate correctly:

If any of these differ from your workshop, tell Yuantai before ordering — each change affects price and lead time on the double girder underhung crane.

350~1500mm rail width is specified for this double girder underhung crane because:

• Wide range covers multiple rail options: The 350~1500mm range allows the crane to fit various runway rail widths, from narrow 350mm to very wide 1500mm — giving flexibility in the runway design
• 40.2 kN max wheel load: The wheel load from the double girder crane plus the crab trolley requires a robust rail section within this range
• 19m span load moment: The wide span creates a significant load moment at the end carriages, requiring appropriate rail width for stability
• Double girder weight: The two girders plus crab trolley are heavier than a single girder, contributing to the wheel load
• Standard availability: Rail widths within the 350~1500mm range are common and easy to source or replace

Do not substitute a narrower rail outside the specified range without recalculating the wheel load and dynamic forces. The 40.2 kN wheel load and 19m span require a rail within the 350~1500mm range or equivalent.

No — this double girder underhung crane is configured for indoor workshop use as a double girder underslung crane, double girder bridge crane, or double girder ceiling mounted crane. The crane runs on elevated runway rails supported by the building structure. Outdoor use would require:

• Different crane type: A gantry crane with ground rails and A-frame legs is usually more suitable for outdoor use
• Weather protection: Outdoor-rated electrical enclosures (IP55+) and anti-corrosion treatment — especially important for the VFD panel
• Wind load design: Anti-wind devices and anchoring — critical at 19m span where wind loads are greater
• Rain cover: Protect the crane, crab trolley, and electricals from rain and snow

For outdoor applications, consult Yuantai Cranes for a suitable gantry crane or a weather-protected double girder underhung crane solution.

To avoid surprises at installation, these items are outside the double girder underhung crane supply scope unless you specifically add them:

• Runway rail (350~1500mm) and rail fasteners
• Runway beam and building column reinforcement
• Building structural support for the 40.2 kN wheel load — especially important at 19m span
• Site power supply up to the crane isolator
• VFD panel installation space and cable routing
• Square bar 40×40 trolley rail (if not included in the crane package)
• Erection crane and site lifting equipment for the double girder bridge
• Local electrical connection and permits

Because the double girder underhung crane is heavier than a single girder crane and runs on elevated runway rails at a wide 19m span, the building structure and installation access are critical — the runway beam and columns must support the 40.2 kN wheel load, and the installation must be planned for the double girder bridge weight. Yuantai can provide runway load drawings and installation guidance as optional items.

Send these eleven items and Yuantai will issue a free custom double girder underhung crane CAD drawing and proposal within 24 hours:

1. Required lifting capacity (t) — e.g., 3t
2. Crane span (m) — e.g., 19m
3. Required lifting height (m) — e.g., 7m
4. Trolley rail gauge (m) — e.g., 1.4m
5. Long travel rail width (mm) — e.g., 350~1500mm
6. Number of double girder underhung cranes required (e.g., 1 unit)
7. Building clear height and roof structure capacity
8. Power supply (V / Hz / Ph) — e.g., 380V 50Hz 3P
9. Duty class — e.g., M5
10. VFD scope — hoist only or full VFD
11. Control requirement — e.g., pendant + remote

The more complete the list, the faster and more accurate the double girder underhung crane drawing and quote.

This published double girder underhung crane drawing and 3D rendering are a free technical reference — you may use them to plan your workshop and check fit. A project-specific double girder underhung crane GA drawing and 3D model are also free for standard configurations. A design fee may apply only for complex workshop conditions, non-standard spans, specialized crab trolley designs, or customized VFD and control requirements. The double girder underhung crane drawing remains the property of Yuantai Cranes: unauthorized copying, use, or manufacturing without written authorization is strictly prohibited.