Introduction
Most facilities buying their first overhead crane focus on capacity and price, then discover the equipment doesn’t match their building height, bay width, or duty pattern. The single girder EOT crane—Electric Overhead Travelling—solves light to moderate material handling requirements at 30-40% lower cost than double girder alternatives, but only when specified correctly. Here’s the uncomfortable truth: most buyers underestimate how much component quality determines long-term reliability, not just purchase price. This guide covers every major component, the features that separate well-built systems from budget ones, technical specifications, and the applications where single girder design delivers optimal value.
Main Structural Components
The bridge girder is a single horizontal beam of fabricated steel, typically box-section construction. Grade IS 2062 or equivalent structural steel, stress-relieved after welding, resists deflection under repeated loading.
End carriages attach to both ends of the girder and carry the wheel assemblies that travel along runway rails. Drive end trucks include geared motors; non-drive end trucks use passive wheels. Alignment between end trucks determines travel straightness and wheel wear.
Runway beams and support columns form the fixed infrastructure. These carry all dynamic and static loads from the crane system and must be structurally verified before installation.
Lifting and Hoisting System
The electric wire rope hoist is the core lifting unit. It consists of a drum motor, gear reducer, rope drum, wire rope, and hook block assembly mounted on the trolley.
The trolley travels along the bottom flange of the bridge girder on precision-machined wheels. Cross-travel speed typically runs 2-20 metres per minute depending on application requirements.
Hook blocks include safety latches, swivel bearings, and forged-steel hooks rated to the crane’s working load limit. The sheave arrangement determines load travel ratio and lifting speed.
Electrical and Control Components
Bridge and trolley drive motors typically use AC squirrel cage or variable frequency drive (VFD) systems. VFD controls allow stepless speed adjustment from near-zero to full speed, cutting load swing and improving positioning accuracy.
Control panels house motor starters, overload relays, and protection circuits. Pendant controls hang from the bridge for operator use at floor level. Radio remote controls add mobility for complex multi-point lifts.
Power delivery uses either a conductor busbar system or cable festoon along the runway. Busbar suits permanent high-use installations; festoon suits shorter spans and lower duty cycles.
Safety and Limit Devices
Every properly built single girder EOT crane includes a defined set of protection devices:
- Overload protection relay: cuts power when load exceeds rated capacity
- Upper and lower limit switches: prevent hoist over-travel in both directions
- Bridge and cross-travel limit switches: stop movement at runway and girder ends
- Emergency stop: accessible from pendant and remote controls
- Electromagnetic brakes: hold loads during power interruption
- Slack rope detection: protects wire rope from coiling damage
These are not optional extras. Missing any one of them creates liability and operational risk.
Key Features
Single girder design concentrates key advantages in three areas:
Space efficiency: The hoist runs on the bottom flange of the girder, keeping the overall crane height lower than double girder alternatives. Facilities gain 300-500mm of additional hook height from the same building envelope.
Lightweight construction: The single beam weighs 30-40% less than a comparable double girder bridge. Lighter runway beams, simpler support columns, and reduced foundation loads follow.
Modular assembly: Sections bolt together on site rather than requiring heavy lifting equipment for installation. A 10-ton crane with 15-metre span typically assembles in 2-3 days.
Technical Specifications
Standard single girder EOT crane parameters:
- Capacity: 1-20 tons (most applications use 1-10 tons)
- Span: 7.5-31.5 metres
- Lifting height: 3-30 metres depending on hoist and building height
- Lifting speed: 0.5-12 metres per minute
- Bridge travel speed: 20-80 metres per minute
- Duty class: A3-A5 (light to moderate use cycles)
- Work environment: -20°C to +40°C standard
Benefits and Advantages
Cost advantages extend beyond purchase price. Installation runs 40-50% faster than double girder systems, reducing labour and downtime costs.
Maintenance access is simpler. Fewer structural components mean fewer inspection points. Annual maintenance costs run 20-30% lower than double girder systems for equivalent capacity.
The 25-35% lower purchase price versus double girder at equivalent tonnage recovers in under two years for facilities with moderate duty cycles.
One underappreciated advantage: single girder cranes suit retrofit projects in buildings with limited structural capacity. The lighter weight fits buildings that would require reinforcement for double girder systems.
Applications and Use Cases
Single girder EOT cranes work across a wide industrial range:
- Warehousing and logistics: pallet handling, loading dock operations, storage retrieval
- Manufacturing: component assembly, machine loading, work-in-process movement
- Automotive: sub-assembly handling, parts feeding to production lines
- Pharmaceuticals and food processing: clean-room compatible variants with sealed electrical systems
- Light fabrication and maintenance: workshop bays, equipment service areas
The 10-ton capacity threshold covers approximately 80% of light manufacturing material handling requirements, making single girder the dominant crane type in these sectors.
FAQs
What’s the maximum practical span for single girder EOT cranes?
Standard designs handle up to 31.5 metres. Beyond 25 metres, girder deflection becomes a design constraint and engineers specify heavier section beams. Above 31.5 metres, double girder construction becomes structurally and economically preferable.
How long does installation take?
A standard 5-10 ton single girder crane with 15-metre span installs in 2-4 days including runway installation, crane assembly, electrical connection, and load testing. Larger spans or complex buildings extend this to 5-7 days.
Can single girder cranes handle continuous shift operations?
Yes, within their duty class. A3 suits 8-hour intermittent use. A5 handles moderate continuous cycles. Beyond A5, double girder design provides the structural durability heavy-duty continuous operations demand.
What’s the difference between wire rope and chain hoists?
Wire rope hoists suit heavier capacities (1 ton upward) and longer lift heights with higher speed. Chain hoists suit lighter loads (up to 5 tons) in compact applications with lower lift heights. Wire rope systems are standard for most industrial single girder EOT applications.
How do VFD drives improve performance?
Variable frequency drives allow smooth acceleration and deceleration, cutting load swing on every move. They extend motor and brake life by reducing mechanical stress. Positioning accuracy improves from ±50mm on standard contactors to ±5mm with VFD control.
Conclusion
Single girder EOT cranes cover 1-20 ton capacities with lower purchase cost, faster installation, and simpler maintenance than double girder alternatives. Component quality—girder fabrication, hoist selection, safety devices, and control systems—determines whether that cost advantage holds across 15-25 years of service.
Contact us to specify a single girder EOT crane matched to your capacity, span, duty cycle, and building constraints.
Heben Cranes manufactures single girder EOT crane systems from 1 to 20 tons with complete in-house fabrication, quality-controlled component selection, and engineered specifications matched to your facility. Our team verifies building structural capacity, designs runway systems, selects hoists and control configurations for your duty requirements, and manages complete installation with load testing and operator training. Every crane includes overload protection, limit devices, emergency stop systems, and full documentation to IS 3177 compliance standards. We back every installation with scheduled maintenance programmes and regional technical support for 15-25 year service lives. Visit hebencranes.com to discuss your material handling requirements and receive a detailed specification and quote for your application
