LH vs QD Bridge Crane: Which Fits Your Workshop?
The fundamental difference between an LH-type overhead crane with electric hoist and a QD-type double-girder bridge crane lies in the hoisting mechanism—the LH uses a lightweight electric hoist design, while the QD employs a trolley-mounted winch system. Choosing the wrong model means either overspending or significantly shortening the equipment's service life.
Why LH and QD Cranes Are Often Confused—and the Key Difference
Many first-time buyers of overhead cranes find themselves torn between the LH and QD models—both feature a double-girder configuration, yet their price tags differ dramatically. The real distinction lies in the hoisting mechanism: the LH uses an electric hoist as its lifting device, delivering a compact, lightweight design, while the QD employs a trolley-mounted winch system built for heavy loads and high-frequency duty cycles. In short, the LH is the "light-duty option" and the QD is the "heavy-duty workhorse." Picking the wrong one means either paying for capacity you don't need or watching the equipment fail well before its time. This article breaks down the differences across five key dimensions—hoisting mechanism, lifting capacity, price, work duty classification, and maintenance costs—to help you make the right call.
LH-Type Overhead Crane with Electric Hoist: A Closer Look
2.1 Structural Features
The LH-type overhead crane with electric hoist—often shortened to LH crane or electric hoist bridge crane—consists of five main assemblies: twin main girders, end carriages, an electric hoist hoisting mechanism, a crane travel mechanism, and an electrical control system. Unlike the LD single-girder design, the LH features a box-type structure with two main girders. The electric hoist is mounted on a trolley frame that travels along rails on top of the twin girders, offering greater load capacity and stability than the LD type. Compared to the QD double-girder crane, the LH's hoisting mechanism uses a standard electric hoist (CD1/MD1 series) rather than a trolley-mounted winch, making it more lightweight and cost-effective.
| Component | LH Type Configuration | Description |
| Hoisting mechanism | CD1/MD1Electric Hoist | Hoist Mounted on Trolley Frameon, Trolleyalongtwin main girders Crane Railtravel |
| Main Girder | box-typedouble girder | two-girder Main Girder, lower steel consumption than QDbut higher than LD |
| Long Travel / Bridge Travel | Geared Motor Unit (All-in-One) | Variable Frequency Drive (VFD)/Two-Speedoptional |
| Operation Mode | Pendant Control+remote control | Standard Configuration |
2.2 Application Scenarios
The LH Type overhead crane with electric hoist typically offers a lifting capacity range of 5t to 50t with spans from 7.5m to 31.5m, and a work duty classification of A3 to A4. Thanks to its lightweight construction and cost-effectiveness, it is ideally suited for the following applications:
- Warehouses & Transfer Stations: Low-frequency cargo handling with individual loads ≤20t
- Light Industrial Facilities: Machinery processing, assembly workshops, and maintenance bays
- Small-to-Medium Workshops: Lifting frequency ≤30 cycles/hour with average daily operation ≤4 hours
Kelude's LH series overhead crane with electric hoist features a Q235B (≈S235JR) main girder and integrally heat-treated end carriages. Standard equipment includes an anti-skew limit device and an audible and visual alarm, with optional remote control and variable-frequency speed control to ensure safe, efficient operation under light-duty conditions.
QD Type Double-Girder Bridge Crane: A Comprehensive Overview
3.1 Structural Features
The QD type double-girder bridge crane—commonly referred to as the QD bridge crane or simply the double-girder crane—is the workhorse of the overhead crane family. It employs a box-type twin main girder design combined with a trolley-mounted hoisting mechanism, where the hoist winch is installed on the trolley frame, allowing the trolley to traverse along rails atop the main girders. This configuration delivers significantly greater structural rigidity and stability compared to electric hoist designs, making it well-suited to withstand the repeated impact loads of high-frequency lifting operations.
| Component | QD Type Configuration | Description |
| Hoisting mechanism | Trolleytype Hoist Winch(YZRMotor+Gearbox / Reducer+Drum) | independent Trolley Frame, Dual Brake |
| Main Girder | box-typedouble girder, stiffener plate | high steel consumption, high load capacity |
| Long Travel / Bridge Travel | YZRMotor+Gearbox / Reducer+Brake | hardened tooth flank Deceleration, impact-resistant |
| Operation Mode | Operator Cabin+remote control | standard Operator Cabin |
3.2 Application Scenarios
The QD Type double-girder bridge crane offers a lifting capacity from 5t to 500t with spans ranging from 7.5m to 35.5m, and is available in work duty classifications from A5 to A7. Typical applications include:
- Steel Mills & Metallurgical Workshops: Ladle handling and continuous casting slab loading, requiring hoisting mechanisms with high-temperature resistance and radiation protection.
- Heavy Machinery Manufacturing: Lifting large machine tool workpieces and assembling heavy equipment.
- Hydroelectric & Nuclear Power Plants: Installation of generator rotors and other large components.
- Ports & Storage Yards: High-frequency loading/unloading operations with daily duty cycles of 8 hours or more.
Kelude's QD series double-girder bridge cranes feature a Q345B (≈S355J2) main girder and hardened gear reducer. The hoisting mechanism is equipped with a dual-brake system (electro-hydraulic plus mechanical) for enhanced safety redundancy. Custom configurations are available upon request, including explosion-proof, insulated, and metallurgical-duty versions.
LH vs. QD: Key Comparison
| comparison item | LH Type Electric Hoistoverhead | QD Typedouble girderoverhead |
| Hoisting mechanism | CD1/MD1Electric Hoist, Hoistalong I-Beamtravel | Trolleytype Hoist Winch(Motor+Gearbox / Reducer+Drum+Pulley Block), Trolleyalong Crane Railtravel |
| Lifting Capacityrange | 5t~50t | 5t~500t |
| Spanrange | 7.5m~31.5m | 7.5m~35.5m(customizable for larger) |
| Work Duty / Classification | A3~A4(light-medium) | A5~A7(medium-extra heavy duty) |
| Lifting Speed | Single-Speed8/Two-Speed8+0.8m/min | multi-level adjustable, commonly used5~20m/min |
| price comparison | base price(100%) | price comparison40%~80% more expensive than LH |
| structure Weight | light(low steel consumption, Factory buildinglow load capacity) | heavy(high steel consumption, high foundation requirements) |
| maintenance cost | low(Electric Hoist Standard-ized, readily available parts) | high(Trolleycomplex system, professional Maintenance) |
| Factory buildingrequirement | rail height can be as low as6m | rail height typically≥9m, requires large column spacing |
| typical service life | 10~15years(light-duty application) | 20~30years(including Overhaulrotation) |
Note: The price ratios above are market reference prices based on LH=100%. The actual premium for QD models may vary depending on lifting capacity, span, and special configurations (explosion-proof, insulated, or metallurgical). We recommend requesting a detailed quotation from Kelude Heavy Industry.
Selection Guide: Two Key Criteria to Consider
Criterion 1: Evaluate Lifting Capacity
| condition | recommended Model | rationale |
| Lifting Capacity≤20t | LH Type Electric Hoistoverhead | LH's electric hoist hoisting system fully meets light-duty requirements up to 20t, compact design, low cost |
| Lifting Capacity>20tand<50t | requires evaluation Work Duty / Classification | infrequent operation LHcapable of handling; for frequent operation, recommended QD |
| Lifting Capacity≥50t | QD Typedouble girderoverhead | 50tabove this tonnage, must use QD Type Trolleytype Hoist Winch, LHof Electric Hoistcannot handle |
Standard 2: Check the Duty Cycle
| light-duty application | daily operating time | per hour Liftingcycles | recommended Model |
| intermittent duty | ≤2per hour | ≤10cycles | LH |
| normal duty | 2~4per hour | 10~30cycles | LH(low tonnage)/ QD(high tonnage) |
| high-frequency duty | 4~8per hour | 30~60cycles | QD |
| continuous heavy-duty | ≥8per hour | ≥60cycles | QD(A6/A7Level) |
Quick Selection Guide
Up to 20 tons with light duty? Choose LH Type to save cost and weight.
Heavy loads and high frequency? QD Double-Girder is the safe choice.
Not sure? Send us your parameters and Kelude will tailor the right solution.
Two Solutions from Kelude Heavy Industry
Henan Kelude Heavy Industry Co., Ltd. operates a 50,000 m² production base and holds a Class A crane manufacturing license. We produce both LH Type electric hoist overhead cranes and QD Type double-girder bridge cranes, covering a full range of lifting capacities from 1t to 300t.
Whether you run a light-duty factory, a warehouse transfer hub, a steel mill, or a power plant installation site, Kelude Heavy Industry can deliver a solution matched to your actual lifting capacity, span, and work frequency — complete with structural calculation reports and factory inspection certificates.
Consultation hotline: You're welcome to visit our plant or send us your workshop parameters. The Kelude engineering team will provide free drawings and quotations.
To compare parameters and pricing across the full range of overhead crane models, check the Complete Overhead Crane Selection Comparison Table — a single page that explains the differences between LD, QD, LH, LB, and LDY models.
Related Standards
• JB/T 3695 — Electric Hoist Overhead Crane
• GB/T 6974.7-2008 — Cranes — Terminology — Part 7: Floating Cranes
• ISO 12480-2:2008 — Cranes — Safe Use — Part 2: Mobile Cranes
Frequently Asked Questions
Q: Which is more cost-effective — LH Type or QD Type?
A: It depends on the application. For lifting capacities up to 20t with intermittent duty (4 hours or less per day), the LH Type is the right choice — it costs roughly 30–40% less than the QD Type. For capacities above 20t or high-frequency heavy-duty operation, the QD Type is required — it costs more upfront but delivers a longer service life and lower maintenance costs. Kelude Heavy Industry offers both options for side-by-side comparison.
Q: What is the maximum work duty for the LH Type?
A: The LH Type is rated for standard work duty of A3 to A4, with certain configurations reaching A5. The QD Type, by comparison, can achieve A5 to A7 and even A8. If your operation requires more than 8 hours of daily use with frequent full-load lifts, the QD Type is the only viable option — the electric hoist hoisting mechanism on the LH Type experiences a significantly higher failure rate under heavy-duty conditions.
Q: Which model suits a low-headroom factory building?
A: The LH Type uses an electric hoist for lifting, which occupies significantly less headroom than the QD Type — making it the preferred choice for low-headroom retrofit projects. The LH Type can operate with a rail height as low as 6 m, while the QD Type typically requires a minimum rail height of 9 m. If your workshop height is constrained, the LH Type is the more practical solution.
Q: What advantage does the dual-brake configuration on the QD Type offer?
A: The QD Type hoisting mechanism is equipped with dual brakes (electro-hydraulic plus mechanical). If one brake fails, the other can still reliably hold the rated load. This is an essential safety feature for applications with extremely high safety requirements, such as metallurgical plants and power stations. The LH Type comes with a single brake (the cone brake built into the electric hoist), which provides adequate safety for light-to-moderate duty applications.
