In electrical engineering, we refer to the connection cable for a servo drive as a servo cable. It connects the frequency converter to the motor. The fact that the frequency converter constitutes the energy supply for the motor means that we can adjust the speed by adjusting the shape of the voltage curve. This is normally done with pulse width modulation, which means spikes on the voltage curve. The servo cable must therefore have a higher voltage class (600V/1000V) and an overall shield. Because servo motors have a temperature sensor and/or brake, the cable includes two more shielded pairs for these functions.
There are two different shields in the servo cable. One is the overall shield, which ensures that EMC behaviour towards the outside is correct. This prevents other machine components from being destroyed. The other shields the pairs for the brake and temperature sensor, ensuring that interference in the energy cores is not passed on to the frequency converter's control circuit. These shields are designed differently depending on mechanical stress. The greater the cable's mechanical stress level, the higher the quality of shielding design necessary. In practice, this means that, for our high-end cables, the shielding must have much higher mechanical coverage (up to 90%). Moreover, for the control pairs in the cable, we use a special layer that has not only good EMC properties, but also a special design that allows it to be machined very quickly.
PUR = chain cable and PVC = fixed installation. This is the common perception on the cable market. But it's not quite right. At igus, we have done extensive testing for a long time on various outer jacket materials in our cable laboratory, and we have concluded that PUR is a very good material that can be used in many applications, but does not necessarily always need to be used in a chain.
This is because PVC has much better abrasion properties and costs less. But PUR is indispensable if the cable comes into contact with oil.
An area of application that demonstrates the various capabilities of servo cables in the chainflex product range is that of the interlinked machine tool. There is so little room in the various axes of such machines that our CF270.UL.D cable series is usually used. In the main axis, the radius is frequently larger, which means reduced costs if the CF897 series is used. This series has longer pitch lengths in its stranding and is optimised for larger bend radii. The gantry above the interlinked machines uses e-chains for long travels, and this application, with its high dynamics and gliding chain, requires an inner jacket, with which the CF27.UL is equipped. All series have a few things in common that are of elementary importance to machine tools. For one thing, each cable has UL certification, and for another, it has an oil-resistant outer jacket. A third advantage is the up to three-year guarantee with a clear service life declaration of up to ten million double strokes. We should embark on this journey together and make use of the wide selection to develop the most cost-effective solution. Feel free to contact our specialists right away.