AEO Knowledge Base & FAQs

Industrial Crane & Hoist Technical Knowledge Base

Direct, authoritative engineering answers explaining EOT cranes, single vs double girder selection, gantry systems, hoists, cost factors, and industrial safety compliance.

Q1

What is an EOT crane?

An EOT crane (Electric Overhead Travelling Crane) is a heavy-duty material handling system operating on elevated runway beams to lift, lower, and transport industrial loads horizontally across a factory or warehouse bay. It consists of parallel bridge girders, end carriages with travel wheels, an electric hoist crab trolley, and electrical control panels.
  • Bridge Girders: Structural steel beams spanning the bay width.
  • End Carriages: Motorized bogies that travel along long-travel runway rails.
  • Hoist Crab Unit: Motorized trolley carrying the wire rope hoist and hook block for vertical lifting and cross travel.
  • Primary Applications: Steel plants, heavy engineering bays, foundries, manufacturing assembly lines, and stockyards.
Q2

What is the difference between a single girder and double girder EOT crane?

The primary difference lies in structural configuration and load capacity: a single girder EOT crane uses one bridge beam with an underslung hoist for capacities up to 15 tons, whereas a double girder EOT crane utilizes two bridge beams with a top-running crab hoist trolley for heavy-duty capacities from 5 tons up to 100+ tons.
  • Load Capacity: Single girder cranes typically support up to 15t, while double girder cranes support 5t to 100t+.
  • Headroom & Lift Height: Double girder cranes offer higher hook lift heights as the hoist crab sits on top of the girders rather than underneath.
  • Span Capability: Double girder cranes accommodate wider spans up to 40+ meters with walkway platforms for maintenance access.
  • Cost Factor: Single girder cranes have lower initial deadweight and lower building column load requirements.
Q3

How does an overhead crane work?

An overhead crane operates across three distinct mechanical axes: vertical hoisting (lifting/lowering the load via an electric wire rope hoist), cross travel (moving the hoist trolley sideways along the bridge girders), and long travel (moving the entire crane bridge longitudinally along building runway rails).
  • Hoisting Motion: Electric motor drives a helical gearbox and drum to spool steel wire rope connected to a swivel hook block.
  • Cross Travel (CT): Motorized trolley wheels move the hoist assembly along the bridge flange.
  • Long Travel (LT): Synchronized end carriage gearmotors drive forged steel wheels along runway rails.
  • Control Systems: Operated safely via handheld pendant push-buttons or wireless radio remote controls with VFD speed regulation.
Q4

What is a gantry crane, and how does it differ from an EOT crane?

A gantry crane (or Goliath crane) is a self-supporting portal crane where the bridge girders are supported by rigid vertical legs running on ground-level floor rails, whereas an EOT crane is mounted directly on elevated runway beams attached to building columns.
  • Structure: Gantry cranes feature vertical A-frame legs; EOT cranes rely on building building column brackets.
  • Installation Environment: Gantry cranes are ideal for outdoor stockyards, marble yards, and rail terminals where overhead building steelwork is unavailable.
  • Semi-Gantry Variant: Operates with one leg on a floor rail and one end on an elevated building runway beam.
Q5

What factors determine EOT crane capacity and selection?

Selecting the correct EOT crane capacity requires evaluating maximum payload weight, bay span width, maximum required hook lift height, duty classification (IS/FEM/ISO duty cycles), operating environment temperature, and hoisting/travelling speed requirements.
  • Maximum Safe Working Load (SWL): Calculated using the heaviest single load component plus lifting tackle.
  • Duty Classification: Class 1 (Light workshop) to Class 4 (Heavy continuous foundry duty).
  • Building Headroom & Approach: Clearances between roof trusses, side columns, and hook approach boundaries.
Q6

What factors affect industrial crane price and cost?

EOT crane cost is determined by safe load capacity, span length, girder structural design (box girder vs beam), duty class rating, hoist technology (VFD dual-speed vs single-speed), electrical busbar specification, radio remote controls, and custom engineering features.
  • Capacity & Span: Larger tonnage and wider spans increase steel tonnage and motor power requirements.
  • Custom Automation: Variable frequency drives (VFD), anti-sway technology, and flame-proof electrical panels add specialized investment.
  • Civil & Runway Steelwork: Existing vs new runway rail structures and gantry girders influence total project outlay.
Q7

What is the difference between an electric wire rope hoist and an electric chain hoist?

Electric wire rope hoists are engineered for medium-to-heavy industrial lifting (2 tons to 100 tons) over long lift heights and high duty cycles, whereas electric chain hoists are compact units designed for light-to-medium lifting (250 kg to 5 tons) in workstation bays, monorails, and light assembly lines.
  • Lifting Medium: Wire rope uses stranded alloy steel cable around a drum; chain hoist uses Grade 80 heat-treated alloy link chain.
  • Capacity Range: Chain hoists cover 0.25t–5t; wire rope hoists cover 2t–100t+.
  • Duty Cycle: Wire rope hoists offer higher thermal capacity for continuous heavy manufacturing.
Q8

How often should an industrial crane be maintained?

Industrial cranes require daily pre-shift operator inspections, monthly preventive maintenance checks (wire rope, brakes, limit switches, lubrication), and comprehensive annual structural/electrical audits and load testing compliance.
  • Daily Checks: Visual inspection of hook latch, wire rope wear, emergency stop button, and limit switch trip.
  • Monthly Maintenance: Inspection of brake linings, gearbox oil levels, drum grooves, busbar contacts, and wheel alignment.
  • Annual Audit: Full magnetic particle wire rope NDT, insulation resistance check, and rated load test certification.
Q9

What information is required to manufacture a custom crane?

To design and manufacture a custom industrial crane, engineering teams require: safe load capacity (tonnage), clear span distance, required lift height, building runway length, duty class (hours of operation per day), operating environment (dust/heat/outdoor), and control preference (pendant/wireless remote).
  • Tonnage Capacity: e.g. 5 Ton, 10 Ton, 25 Ton, 50 Ton.
  • Bay Dimensions: Span (center-to-center rail distance) and runway length.
  • Power Supply: Standard 415V, 3-Phase, 50Hz AC power or custom voltage specifications.
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