Some of the latest green cable management systems can
provide up to 57% energy consumption savings compared
with traditional systems, says Justin Leonard, director at
igus UK. Here, he reviews the latest polymer energy chain
technologies and advises how engineers can reduce energy
loss and operate machinery cost effectively

With demand for manufacturers to
increase energy efficiencies and
reduce costs of their operations,
plant managers and engineers are reviewing
all aspects of their facilities to identify where
energy savings can be made. A key aspect of
machines are the energy chains used to carry
cables for power transmission, electricity and
fluids, as well as sensitive bus, data and fibre
optic cables.

Reducing drive power
Energy chains are an important part of many
machines, being the principle method of
carrying, guiding and protecting moving
cables and hoses. Lubricant-free plastic
energy chains can be used unsupported for
shorter travels or gliding for longer travels.

Despite being made from lightweight but
robust technical plastics, they still have a
direct influence on how much energy is used
in the plant. How much push-pull force, in
other words drive power, is required at a
given speed to move an energy chain affects
how energy efficient it is. The more power
that is required, the more energy is required,
and therefore it will cost more to operate.

Thus, by reducing drive power, energy usage
and costs can be reduced. Friction, size and
weight of the overall system all determine
how much drive power is required and how
much energy is used.

For shorter unsupported travels, lighter
cable management systems mean less energy
required. This in turn means that smaller
motors, drive control and frequency
converters can be used. Newer energy
chains, such as the igus E4.1 system have
various design features which add strength
without adding weight, so in many cases a
smaller, lighter size of energy chain can now
be used for the same application
requirements. This means up to 17% drive
power can be saved.

Traditionally gliding energy chains, i.e.

where the upper run slides on the lower run,
are used on longer machine axes. These
modular systems have been used effectively
for many years, however, as the top run
moves over the bottom run, extra friction is
incurred.

In recent years, energy chains have been
developed that incorporate rollers, which
significantly reduce friction and therefore
energy loss. Tests at igus have proven that for
the same application conditions (fill weight,
chain length, speed and acceleration) it has
been possible to reduce the friction factor
from 0.3 to less than 0.1. On travel distances
of 40 to 50m and more, that reduces the
electricity and operating costs significantly.

In this way, the igus rol e-chain provides a
reliable solution for long travel lengths of up
to 800m, speeds to 6m/s and for cable loads
up to 50kg/m. The steady rolling resistance
in machine applications, even in dusty and
dirty conditions, means users can realise
energy savings of up to 37%.

The energy chain system P4 from igus, for
example, takes this further. It also features
rolling technology and has been developed
for plant and machinery manufacturers on
applications such as loading gantries for
automated production processes, where
speeds are getting even higher, (up to 10
m/s) and travel lengths longer (to 800m and
more). In this way the energy consumption
saving can be even greater.

Cable selection
Having chosen an energy efficient cable
carrier, other aspects to consider are the
quality of the cables themselves as cables
especially designed for energy chains can
also help directly in reducing energy
consumption. Optimised sheathing mixtures,
matched to the energy chain application, can
achieve low abrasion resistance. High-quality
sheathing materials can be extruded with an
extremely thin wall, which saves up to 18%
in weight compared with conventional
cables.

Cable insulation materials should also be
considered. With high-quality materials,
significantly higher currents can be carried
through the same electric cross-sections, or
vice versa, the cross-sections can often be
reduced without the electrical performance
being diminished. This allows weight
reductions of up to 30%.

The use of the correct cable sheathing and
insulating materials can ultimately save drive
power requirements by up to 17%.

By understanding all aspects for reducing
the driving power, energy efficiency of a
plant can be increased significantly. Through
installing high quality energy chains and
flexible cables from a supplier that can
provide sound advice and guidance,
engineers can make energy consumption
savings of up to 57% in total.