Why energy chains are better for power supply in overhead cranes

Reliable and dynamic cable management is one of the greatest challenges
in modern crane technology. Virtually all modes of crane applications are
facing intensifying requirements regarding travel distances, speeds and
precision. In the international overhead crane market where various standards
come into play, manufacturers and end-users seek electrification solutions that
can be adapted to the respective scenario. While the components must be modular,
they should also be consistently easy to install, low maintenance and
cost-effective. Engineers often turn to two power supply variants to try and
meet these demands: festoons and energy chains.

Festoon systems are designed to provide direct electrification with flat
or round cables. The cables in festoons are hung from trolleys that stack
together at the end of the crane rail. While this structure provides defined
linear guidance, it consumes space on the crane rail, limiting the amount of
crane travel that can be accomplished in a given dimensional window. As the
cables are essentially clamped in bunches, it makes replacement or addition of
cables a time-consuming process. The festoon design also incorporates a variety
of linked components, including wheels, tow cables, shock cords and bearings.
Each individual part requires regular maintenance and lubrication, especially
when exposed to rough operating environments.

In festoon systems, cables and hoses hang loose while guided.
Unprotected, the lines can swing, become tangled and get caught in the crane
structure, especially during harsh weather, which leads to costly repairs.
Often, festoons use flat composite cables consisting of multiple conductors in
a single jacket. When these cables are used, the entire composite cable may
need to be replaced if one conductor becomes damaged. For instance, ship-to-shore
cranes are often found to be equipped with festoons. As this application
environment is exposed to high winds, heavy rain, ice and other barriers,
festoon users face high costs for repairs caused by wear and weather. This
means further downtime wasted on maintenance and inspections. The hanging
cables and steel-dominated structure of festoons also requires ample space for
setup.

To avoid the maintenance and costs that come with festoons, users are
increasingly using an alternative electrification system – the energy chain.
The high performance plastic e-chain can take on demanding operating
environments with its corrosion and wear resistant features, yet it has a
simple design and is very easy to install.

The energy chain is designed for optimal efficiency. Cables are securely
guided in the system with interior separators, so cables can never cross over
one another and become tangled. For strain relief, cables are tightly clamped
and can be easily and individually released for repair or replacement. While in
festoons an entire composite cable may need to be replaced if one conductor is
damaged, with e-chains, only the one damaged cable would have to be swapped.
Since the e-chain does not require a loop parking station, a centre-mounted
e-chain system requires approximately 50 percent less cable than a festoon
system. This considerably reduces mechanical stress, system weight and
acquisition costs. With no hanging loops, the required operating window is also
considerably less than festoon systems, noteworthy for applications with
restricted space.

Installation is truly simplified with the e-chain; a guide trough is
installed on the crane girder, and the e-chain is populated with cables and
then installed into the trough. The moving end is attached to the trolley and
the cables are routed to their connection points. Energy chains can be
pre-populated with cables by the energy chain manufacturer, making installation
even more straightforward. Horizontal, vertical, rotary and three-dimensional
movements can also be achieved. While festoon wheels, shock cords and bearings
are marked for wear and require replacement or lubrication, the chains are
maintenance-free, only needing basic visual inspections to ensure the system is
in good working order.

The e-chain is engineered to protect cables from debris and extreme
weather conditions. Due to the clean and durable design, the e-chain is proven
to withstand the most demanding environments. Wind is no match for the system,
as cables are securely guided and cannot get caught at any point. The
predefined bending radius also prevents the cables from being bent below the
manufacturer’s recommended bend radius, which sometimes occurs with
free-hanging festoons. For additional protection, the chains are available with
integrated rollers for extremely long travel distances, as well as special
materials for chemical resistance. The rugged energy chain can be configured in
many different ways, from use on hoist trolleys at high speeds to managing long
runway travels with special requirements. This modularity can be applied to a
wide variety of applications, including both outdoor gantry cranes and indoor
bridge cranes.

The entire range of igus e-chains with over 90,000 variations is available
from Treotham. Most often utilised for crane technology are the heavy-duty E4.1
series chains and the cost-effective E2/000 chains. Crane manufacturers are
progressively reaping the benefits of e-chain solutions, as the carriers are
compliant to standards yet universally applicable – over 30,000 cranes,
worldwide, have been equipped with igus energy chains.

For more information,
please visit the Treotham Automation website www.treotham.com.au or call 1300 65 75
64.

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