Underhung Overhead Crane 3 Ton - S17.5m - A5 × 2 Units for Tandem Lifting

Tandem lifting with two underhung overhead cranes on the same span means the two cranes work together to lift one load that is too long or too heavy for a single crane. In this configuration:

• Two 3t underhung overhead cranes work together to lift up to 6t (2 × 3t)
• Tandem control synchronization is required — both hoists must lift and travel at matched speeds
• Anti-collision protection is critical — the two cranes share the same span and runway
• Load distribution must be calculated — the load must be rigged so both hooks share the weight evenly
• Certification and inspection may be required for tandem lifting depending on local regulations

Tandem lifting is ideal for long loads (e.g., long pipes, beams, or fabricated sections) or heavy loads up to 6t that exceed a single 3t crane. Tell Yuantai your tandem lifting requirement — load length, load weight, and lift points — for a proper tandem lifting calculation.

The 2 units configuration is chosen for this existing workshop with 4 cross beams at 10m spacing and a 40m runway length for one of two reasons:

• Tandem lifting operations: Two 3t underhung overhead cranes can lift a 6t load together (with proper tandem control and certification) — ideal for long or heavy loads
• High-throughput handling: Two cranes on the same span allow one to handle loading while the other handles unloading, doubling handling capacity across the 40m runway

When two underhung overhead cranes share the same span and runway:

• Each crane has its own control station — pendant + remote control for each crane
• Anti-collision protection is critical — the two cranes must not collide during travel along the 40m runway
• Runway rail length must be sufficient — the 40m runway must be long enough for both cranes to operate independently or in tandem
• The 4 cross beams and runway beam must support both cranes — the structural load is higher when two cranes share a runway, with 28.3 kN max wheel load per end carriage

If your workshop has only occasional high-throughput needs, one crane with faster travel may be more economical than two. Tell Yuantai your throughput and tandem lifting requirements for the best configuration.

On this underhung overhead crane with hoist VFD, only the hoisting motion uses variable frequency drive (0.8~5.0 m/min), while crane travel (2.0~20.0 m/min) and hoist travel (1.0~10.0 m/min) are dual-speed. This configuration is chosen because:

• Hoisting precision matters most: The VFD on the hoist gives smooth acceleration and deceleration for precise load placement — critical for synchronized tandem lifting
• Travel speeds are already sufficient: Dual-speed crane travel and hoist travel provide adequate control for most workshop handling across the 40m runway
• 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

If your workshop needs full VFD on all motions (e.g., for very delicate loads or anti-sway requirements during tandem lifting), it can be specified. Contact Yuantai for a full VFD underhung overhead crane.

An NR electric hoist is the standard hoisting mechanism for this 3t underhung overhead crane because:

• Compact design: The NR hoist is compact and fits the underhung bridge crane envelope, maximizing hook height in the existing workshop
• Hoist VFD precision: The hoist VFD (0.8~5.0 m/min) gives smooth, stepless lifting for precise load placement — essential for tandem lifting synchronization
• Higher duty capability: NR electric hoists handle more cycles per hour than basic hoists at the same capacity
• Easy maintenance: The NR design allows easier inspection and servicing of the hoist, motor, and brake
• Proven reliability: NR hoists are widely used in underhung overhead cranes and under running cranes for light-to-medium duty

The NR electric hoist with hoist VFD is matched to the 3t capacity, 6m lifting height, and 1.0~10 m/min hoist travel speed for this application.

Eight numbers on this underhung overhead crane drawing must match your existing workshop, or the cranes 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 underhung overhead crane.

250~450mm rail width is specified for this underhung overhead crane because:

• Wheel diameter Ø160mm — the wheel is designed to run on 250~450mm rail width
• 3t capacity and 17.5m span: The load moment requires a rail with sufficient head width and web thickness
• Underhung crane design: The rail must support the end carriage running on the bottom flange
• Two cranes on same runway: The rail must support the combined load of both cranes, especially during tandem lifting
• Standard availability: 250~450mm rail width is common for underhung overhead cranes, easy to source and replace

Do not substitute a narrower rail without recalculating the wheel load and dynamic forces. The Ø160mm wheel and 3t capacity require 250~450mm rail width or equivalent.

No — this underhung overhead crane is configured for indoor workshop use as an underhung bridge crane or under running crane. The crane runs on elevated runway rails supported by the building structure (the existing 4 cross beams). Outdoor use would require:

• Different crane type — a gantry crane with ground rails and A-frame legs is more suitable for outdoor use
• Weather protection — outdoor electrical enclosures (IP55+) and anti-corrosion treatment
• Wind load design — anti-wind devices and anchoring for outdoor wind exposure

For outdoor applications, consult Yuantai Cranes for a suitable gantry crane solution.

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

• Runway beam reinforcement and building column reinforcement (the 4 existing cross beams must be verified for 28.3 kN wheel load per end carriage, with both cranes considered)
• Building structural support for the underhung overhead crane wheel load
• Site power supply up to the crane isolator
• Erection crane and site lifting equipment
• Local electrical connection and permits
• Anti-collision system between the 2 underhung overhead cranes (optional, recommended for tandem lifting)
• Tandem control synchronization system (optional, required for tandem lifting)

Because the underhung overhead cranes run on elevated runway rails with 2 cranes sharing the same span, the building structure, anti-collision protection, and tandem control synchronization are critical — the runway beam and the 4 cross beams must support the combined wheel load, and the 2 cranes need anti-collision protection and tandem control for safe tandem lifting. Yuantai can provide runway load drawings, anti-collision specifications, and tandem control specifications as optional items.

Send these eleven items and Yuantai will issue a free custom underhung overhead crane CAD drawing, 3D model, and proposal within 24 hours:

1. Workshop width and runway rail center-to-center distance (span) — e.g., 17.5m
2. Required lifting height (m) — e.g., 6m
3. Required lifting capacity per crane (t) — e.g., 3t
4. Required tandem lifting capacity (t) — e.g., 6t
5. Number of underhung overhead cranes required (e.g., 2 units same span)
6. Workshop length / crane travel distance — e.g., 40m runway
7. Building cross beam spacing and capacity — e.g., 4 cross beams at 10m spacing
8. Power supply (V / Hz / Ph) — e.g., 3P 380V 50Hz
9. Lifts per hour or hours per day (duty) — e.g., A5
10. Longest load length and weight for tandem lifting
11. Control preference: pendant, wireless, cabin, or both

The more complete the list, the faster and more accurate the underhung overhead crane drawing, 3D model, and quote.

This published underhung overhead crane drawing and 3D rendering are a free technical reference — you may use them to plan your workshop and check fit. A project-specific underhung overhead 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, or specialized customization engineering (e.g., tandem lifting calculations and anti-collision integration). The underhung overhead crane drawing remains the property of Yuantai Cranes: unauthorized copying, use, or manufacturing without written authorization is strictly prohibited.