Most factories choose EOT cranes by price and capacity alone. They buy a 15-tonne system because it fits the budget. Six months later, the crane runs constantly, the hoist overheats, and the maintenance team discovers the duty class was rated for occasional use, not continuous production. The crane works — until it doesn’t. This guide explains how to match EOT crane type, features, and duty classification to your actual material handling demands. You’ll learn the structural differences between single and double girder systems, the duty class framework that determines component life, and the application-specific features that separate efficient operations from chronic breakdowns.
What EOT Cranes Do in Industrial Operations
EOT stands for Electric Overhead Traveling. The crane moves on rails mounted to the building structure. It covers the full bay length and width without occupying floor space.
The system consists of a bridge girder, end carriages with wheels, a hoist for vertical lift, and controls for operator input. Unlike mobile cranes or forklifts, EOT cranes handle repetitive lifting in a fixed area with precise positioning and no fuel costs.
Capacity ranges from 500 kg to 500 tonnes. Spans reach 40 meters in industrial bays. The crane delivers materials to workstations, moves production between process stages, and loads vehicles at dispatch zones.
Single Girder vs Double Girder: The Core Decision
Single girder cranes use one main beam. The hoist hangs from the bottom flange and travels along it. This design suits capacities up to 25 tonnes and spans up to 20 meters.
The advantages: lower initial cost, simpler installation, reduced building load, and adequate hook height for most workshops. The limitations: restricted lifting height because the hoist sits below the girder, less structural capacity for heavy loads, and limited maintenance access.
Double girder cranes use two parallel beams with a crab mechanism on top. This configuration handles 25 tonnes to 500+ tonnes and spans beyond 40 meters.
The trade-offs: higher structural cost, increased building load requirements, but maximum hook height, integrated maintenance platforms, and capacity for process-duty cycles in steel plants and heavy industry. You pay more upfront. You gain operational flexibility and longer component life under heavy use.
Duty Classes: The Specification Most Buyers Ignore
Duty class defines how hard the crane can work. It’s not about capacity. It’s about cycle frequency, load distribution, and operational hours per day.
India uses IS/BIS classifications from Class I (light) to Class V (heavy). International standards use FEM/ISO designations from M2 to M9.
What the Classes Actually Mean
- M3/Class II: Occasional use, 1-2 hours per day, light loads
- M5/Class III: Standard manufacturing, 8 hours per day, moderate cycles
- M7/Class IV: Heavy production, 16+ hours, frequent full-capacity lifts
- M8/Class V: Process duty for steel mills, continuous operation
A 10-tonne crane rated M3 costs 30-40% less than the same capacity rated M7. The structural steel is thinner. The motor is smaller. The bearings have lower cycle ratings. It works fine for a maintenance shop doing 50 lifts per week. It fails catastrophically in a production line doing 200 lifts per shift.[]
Research shows that 65% of premature crane failures result from duty class mismatch, not component defects. Buyers spec capacity correctly. They ignore the usage profile entirely.
Safety Features That Separate Compliant from Dangerous
Limit switches stop the hoist before it hits the trolley (two-blocking) or unspools rope off the drum. Travel limits prevent collision with end stops or adjacent cranes. These are mandatory, not optional.
Brake systems include hoist brakes that hold the load when power cuts, and travel brakes that stop crane motion. Every motion — hoist, cross-travel, long-travel — needs independent braking. Single-brake systems create drift in wind or on inclines.
Overload protection shuts down lifting before structural damage occurs. Load cells measure actual weight. Torque limiters sense motor load. Either system must trigger before you exceed the safe working load by more than 10%.
Anti-collision sensors detect obstacles or other cranes in the travel path. They reduce speed or stop motion before impact. Plants with multiple cranes operating in the same bay cut collision incidents by 80% when they install active proximity systems.
Control Systems and Operational Efficiency
Pendant push-button controls hang from the crane. The operator walks with the load. This works for slower operations where load visibility matters more than operator position.
Radio remote controls let operators stand at the best vantage point. They improve safety by removing the operator from beneath the load. VFD-based controls provide smooth acceleration, reduced mechanical shock, and 30-40% energy savings over direct-on-line starters.
Cabin controls suit high-bay operations where the operator can’t see the load from ground level. Steel mills and scrap yards use cabin cranes for visibility and environmental protection.[]
Application-Specific Configurations
Steel plants need high-duty cranes with heat-resistant components, cabin controls, and dual hoists for wide loads. Spans reach 40 meters. Capacities exceed 200 tonnes. Duty classes run M7 to M8.
Chemical plants require explosion-proof electrical systems, corrosion-resistant coatings, and sealed components. The crane operates in atmospheres where a single spark creates catastrophic risk.[]
Engineering workshops use single girder cranes with wire rope hoists, radio remotes, and VFD controls. Capacities range from 5 to 20 tonnes. Duty classes sit at M4 or M5 for standard two-shift operations.
Warehouses favor underslung cranes that maximize vertical space, chain hoists for short lifts, and simple controls. The focus is low headroom and cost efficiency, not heavy capacity.
How Heben Cranes Engineers EOT Systems
Heben matches crane type, duty class, and features to your shift schedule, cycle frequency, and load patterns — not industry averages or catalogue specs. We document the duty class calculation so you know the crane is engineered to your actual usage, not under-spec’d to meet a price target.
Our single girder cranes run from 1 to 25 tonnes with VFD controls, sealed bearings, and hardened wheels as standard. Double girder systems handle 25 to 200 tonnes with maintenance platforms, dual brakes, and process-duty ratings for steel, chemical, and heavy manufacturing.
We provide installation support, statutory testing, operator training, and long-term spares availability through regional service centers. When duty requirements change, we retrofit controls, upgrade hoists, or recalculate structural capacity rather than force a complete replacement.
Capacity is one number. Duty class, control type, and safety integration determine whether the crane lasts five years or twenty. Heben Cranes designs EOT systems based on documented usage profiles, not optimistic estimates. Contact us today for a crane specification built to your operational reality, complete with duty class calculations and lifecycle cost analysis.
