Understanding overhead cranes
An overhead or bridge crane is a type of lifting equipment that runs on elevated runways to move heavy goods through a facility. The bridge spans the runway beams and carries a trolley and hoist. The Mazzella Companies, a U.S. crane manufacturer, notes that the bridge is the primary structural component that connects the runways and moves the hoist forward and backward. Two main bridge designs dominate the market: single‑girder and double‑girder cranes. The choice between them determines the crane’s capacity, cost, hook height and ease of installation. In addition to these overhead designs, gantry or goliath cranes run on ground‑level tracks and are commonly used outdoors.
Loadmate Industries Private Limited designs and manufactures electric overhead travelling (EOT) cranes tailored to Indian industry standards. This article explores how to select a suitable EOT crane by examining the differences between single‑ and double‑girder designs, reviewing Loadmate’s product features and highlighting key decision factors such as duty class, capacity and maintenance. By understanding these elements, business owners and engineers can ensure their investment delivers maximum productivity and safety.
Single‑girder EOT cranes: economical and versatile
A single‑girder crane uses one bridge beam supported on end trucks. The hoist and trolley typically run on the underside of the girder, making the system compact. Single‑girder cranes are popular because of their lower cost: the Mazzella article explains that they require less material and are lighter, resulting in cost savings in material, freight and installation. Because they place a smaller load on the building structure, they often can be installed using the existing roof framework rather than adding new columns. The same article lists several advantages:
Economical for light‑to‑medium duty: Single‑girder cranes are the most cost‑effective solution for lighter applications and are ideal for workshops, warehouses, material yards and production facilities.
Better hook approach: With only one girder, the trolley can travel closer to the runway beams, providing a better hook approach for both the trolley and bridge travel. This maximizes the useful lifting area.
Ease of installation and maintenance: Their simpler design makes them quicker to install and easier to maintain than double‑girder systems.
Low headroom: Single‑girder cranes are suitable for facilities with limited vertical clearance.
The main limitations are reduced lifting capacity and lower hook height. The article notes that single‑girder cranes typically are not rated higher than 15 tonnes. Because the hoist runs beneath the girder, they offer less hook height than double‑girder cranes. Specialized features such as walkways, operator cabs or magnet reels can be difficult or expensive to incorporate. Nevertheless, for small to medium factories and warehouses, a single‑girder EOT crane is often the best balance of cost and performance.
Loadmate’s single‑girder design
Loadmate’s single‑girder EOT cranes build on these general advantages while complying with Indian Standards IS‑807 and IS‑3177. The company offers capacities up to 20 tonnes and spans up to 50 metres. Key features include:
Crane‑duty motors and variable speed drives: High‑efficiency motors with dust‑proof enclosures and class‑F insulation provide reliable performance. Inverter‑based drives allow stepless speed variation for smooth acceleration.
Electromagnetic brakes: Dual disc brakes automatically engage during power failure, enhancing safety.
Modular electrical panel: The control panels use reputable components and include overload protection. Their modular layout simplifies troubleshooting and expansion.
Limit switches and travel safety: Over‑hoist and over‑travel limit switches prevent the hook from travelling beyond safe limits, while buffer stops and anti‑collision devices safeguard against collisions.
These features, combined with the inherent advantages of single‑girder design, make Loadmate’s cranes suitable for small production units, warehouses and assembly lines. Optional extras such as radio remote controls, pendant stations and flame‑proof enclosures enable customization for different working environments.
Double‑girder EOT cranes: power for heavy industry
A double‑girder crane employs two bridge beams connected by cross‑bracing, creating a rigid box structure. The trolley rides on rails mounted on top of the girders, allowing for higher hook height. The Mazzella article highlights that double‑girder cranes provide an extra 18–36 inches of hook height because the trolley and hoist are placed between or on top of the girders. They are recommended for heavy‑duty applications with large capacities and long spans. Advantages include:
Unlimited capacity and span: There are essentially no limits to the maximum span or lifting capacity when properly engineered.
Greater hook height: A higher hook position makes it easier to lift bulky equipment and allows stacking or positioning loads at greater heights.
Support for special features: Double girders can accommodate walkways, operator cabs, maintenance platforms, lights and magnet reels.
Indoor and outdoor applications: They are common in mining, iron and steel production, railyards and shipping ports.
The main disadvantages are cost and structural requirements: double‑girder cranes require more material, weigh more and may need extra support columns or tie‑backs. The hoist and trolley are more complex, and installation is longer and costlier. However, when lifting heavy loads is critical to production, the benefits often outweigh the higher initial investment.
Loadmate’s double‑girder engineering
Loadmate’s double‑girder EOT cranes are designed for capacities up to 200 tonnes and come in duty classes M3–M8 to suit everything from light assembly to continuous hot‑metal handling. The bridges are fabricated from box plate or rolled sections, and butt welds can be fully radiographed to guarantee weld integrity. Additional engineering features include:
Walkways and maintenance platforms: A platform along the bridge allows safe access for inspection and maintenance.
Forged steel wheels on anti‑friction bearings: These provide long service life and smooth travel.
Helical and spur gear reducers: Precision‑machined gears run in an oil bath for efficient, low‑noise power transmission.
Microdrive gearboxes: Optional planetary gear arrangements allow slow speeds (5–20 % of main speed) for precise positioning.
Advanced controls: Regenerative braking systems, overload limiters and anti‑collision devices can be added to enhance safety and efficiency.
With these features, Loadmate’s double‑girder cranes are well suited to heavy fabrication, steel mills, shipbuilding and power plants. Custom designs can include auxiliary hoists, tandem operation and remote diagnostics via IoT‑enabled control systems.
Factors influencing crane selection
Selecting the right EOT crane requires evaluating several technical and operational factors. According to a Loadmate blog on efficiency and safety, the crane’s load capacity should match the heaviest load to be lifted and account for dynamic forces. Engineers must also determine the span, lifting height and travel speed appropriate for their facility. Additional considerations include:
Duty class: Loadmate offers categories M3, M5, M7 and M8; choosing the right class ensures the crane’s mechanical parts are rated for the expected frequency and duration of use.
Power and control: Decide whether to use single‑speed or variable‑frequency drives and whether the crane will be controlled via pendant, radio remote or an operator cabin. Modern cranes often incorporate programmable logic controllers (PLCs) and diagnostics.
Environment: For hazardous or explosive atmospheres, flame‑proof motors and non‑sparking components are essential. Outdoor cranes require weatherproof enclosures and corrosion protection.
Building structure: Assess whether the existing building can support the crane’s loads. A double‑girder crane may need additional columns or runway reinforcement.
Installation and service: Plan for the time and cost of installation, and ensure access to maintenance services and spare parts. Loadmate provides installation support and ongoing service contracts.
By analysing these factors alongside budget and production needs, businesses can select a crane that meets performance requirements without overspecifying.
Safety and maintenance considerations
The safe operation of EOT cranes depends on proper training, regular inspections and compliance with regulations. Loadmate’s blog emphasises that operators should be trained in crane operation, safety procedures and emergency protocols. They need to understand the crane’s controls, recognise potential hazards and follow proper rigging practices. Routine maintenance tasks—lubricating moving parts, checking electrical connections, tightening bolts, and inspecting limit switches—are vital for reliability. Detailed inspections should assess the crane’s structural integrity, electrical systems, brakes and control mechanisms.
Loadmate offers maintenance manuals and periodic inspection services. Customers can also purchase annual maintenance contracts for regular check‑ups. Adopting a preventive maintenance schedule reduces downtime and prevents costly repairs. Documenting all maintenance and repairs ensures traceability and helps meet regulatory requirements.
The future of overhead cranes
EOT cranes continue to evolve as manufacturers integrate new technologies. Loadmate’s blog predicts that advancements such as artificial intelligence and the Internet of Things (IoT) will enhance crane performance and safety. IoT sensors can monitor vibration, temperature and load data to detect potential issues before failure. Automated systems can optimise travel paths, reduce energy consumption and improve cycle times. Augmented reality (AR) may assist in maintenance by overlaying digital instructions on physical components.
Customers should also consider sustainability. Modern motors and regenerative braking systems reduce energy usage. Lightweight bridge designs lower the deadweight, which decreases power consumption and wear on runway structures. Using eco‑friendly paint systems and recyclable materials can further reduce the crane’s environmental footprint.
Conclusion
Electric overhead travelling cranes are indispensable tools for material handling across industries. The choice between a single‑girder and double‑girder crane hinges on capacity, span, hook height and budget. Single‑girder cranes offer an economical and versatile solution for light‑to‑medium duty work, delivering cost savings, better hook approach and ease of installation. Double‑girder cranes support heavy loads and large spans, offering greater hook height and the ability to incorporate special features, though they come with higher upfront costs. Businesses should assess load requirements, duty class, building structure and environmental factors when selecting a crane.
Loadmate Industries provides a full range of overhead cranes designed to Indian standards and backed by engineering expertise. Their single‑girder cranes handle up to 20 tonnes and incorporate features such as dust‑proof motors, electromagnetic brakes and modular electrical panels. Double‑girder cranes scale up to 200 tonnes and employ box‑girder construction, forged wheels and microdrive gearboxes for heavy‑duty performance. By offering customized solutions, comprehensive installation support and ongoing maintenance services, Loadmate ensures that customers receive reliable cranes tailored to their operations.
In summary, selecting the right EOT crane is a strategic investment. By understanding the differences between single‑ and double‑girder designs, evaluating operational requirements and partnering with a trusted manufacturer like Loadmate, businesses can secure a lifting solution that boosts productivity, enhances safety and supports future growth.