Calculation of e-chain® lengths and pre-load

How to calculate energy chain length for linear motion

First determine the fixed end – the position of the energy chain connection that does not move. We recommend placing the fixed end in the centre of the travel. This gives you the most cost-effective solution because it requires less energy chain and less cable. The fixed end can also be located away from the travel centre, of course. Chain length is calculated as follows:

The fixed end in the centre of the travel
is always the most cost-effective solution

For unsupported applications

For unsupported applications, the energy chain's upper run moves parallel to the lower run across the entire horizontal travel.

For fixed ends in the centre of the travel

L_k = ^S/₂ + K

Abbreviations	Meaning	Unit
L_K	Energy chain length	[mm]
^S/₂	Half length of travel	[mm]
K	Add-on for bend radius (K is taken from the data tables of the individual series)	[mm]
R	Bend radius	[mm]

For fixed ends off the centre of the travel

L_k = ^S/₂ + ∆M +K

Abbreviations	Meaning	Unit
L_K	Energy chain length	[mm]
^S/₂	Half length of travel	[mm]
K	Add-on for bend radius (K is taken from the data tables of the individual series)	[mm]
∆M	Deviation of the centre point	[mm]
R	Bend radius	[mm]

For gliding applications

On a gliding energy supply, the energy chain glides for one half on the lower run and for the other half on a glide bar.

A = Moving end
B = Fixed end
C = Guide trough with glide bar
D = Guide trough without glide bar
E = Total guide trough length

L_k = ^S/₂ + K₂

Abbreviations	Meaning	Unit
L_K	Energy chain length	[mm]
^S/₂	Half length of travel	[mm]
K₂	Add-on for bend radius if the mounting point height is lowered	[mm]
∆CL	Offset fixed end	[mm]
R	Bend radius	[mm]
D₂	Over length for long travels gliding	[mm]
H₂	Installation height with lowered mounting	[mm]
H_Ri	Inner trough height	[mm]

Pre-load

Pre-load is the curve of the upper run along its unsupported length. Without pre-load, the upper run would sag along the unsupported length under the weight of the inserted cables and hoses. Above a critical value, the energy chain could no longer be guaranteed to operate reliably. That is why igus manufactures all energy chains with pre-load.

Advantages of pre-load:

Longer unsupported lengths
Longer service life and better operating reliability

The required installation height depends on the pre-load of the energy chain with the total value H_F. You can find the dimension H_F on the product pages.