e-spool – the alternative to a cable drum
Lifting devices often require their own power and control supply. To carry out the lifting movement, the energy cables must either be coiled up on a cable drum or stowed away safely in an energy chain and usually in a special basket, such as an igus® “Zig-Zag” system.
However, there are several applications where there is not sufficient installation space to mount a collection basket for an energy chain. In these instances, customers may consider the use of a classic motorised drum solution, but this isn’t necessarily the best solution.
In order to identify the key elements of a corresponding chain solution, it is important to initially understand the fundamental workings of a motorised cable drum.
Motorised cable drum:
A cable guidance system on a drum requires regular maintenance work, which consequently equates to downtime of whatever is being driven by the power source. A motorised cable drum system may contain a slip ring or an integrated motor. Each drive type ensures that the cable is kept under constant tension during the winding and unwinding process. The tensile stress puts a strain on the cable(s) used and has a negative impact on the cable lifetime.
When comparing the two, the e-spool uses an energy chain to absorb any tensile stress. The cables guided inside the chain are therefore protected and not exposed to tensile loads, which is obviously positive when it comes to the life of the cables. Secondly, the e-spool system is completely slip ring- free therefore eliminating the use of maintenance-intensive components, whilst retaining an end-to-end connection. The e-spool is also capable of supporting other media such as air or liquid hoses within the energy chain.
The system is, however, limited to cable or hose diameters of 17mm maximum. As no sliding contact is used with the e-spool, cables or hoses are routed through the system without any interruption. This allows for cable or hose modifications or exchanges at any time. There is some common ground between the e-spool and motorised cable drum types and this is the retention spring. This ensures the constant retention force on the chain.
The motor-driven e-spool is identical to the standard e-spool system described above, with one difference, the retention spring has been replaced by a motor. This as standard, includes all maintenance steps and intervals that are necessary for a trouble-free operation of the electrical motor. The motorised version enables increased travel lengths of up to 25 metres and more, from 14 metres with the spring based system.
As with all energy chain applications, but especially for e-spool applications, only cables specifically designed for use inside an energy chain should be used. The igus® chainflex product line has been designed for such uses and is the perfect accompaniment for the e-spool. For e-spool applications we recommend the use of cables with a TPE outer jacket and for shielded cables even the use of our torsion approved cable line CFROBOT.