Servo Motor Cable

June 2000

For power, signal feedback and control cabling within a servo system look no further than Lapp Cable's ÖLFLEX-SERVO®range designed as a rationalised, space-saving solution for the supply and control of such components.

Lapp Cable's flexible servo motor cables offer many advantages. In the main these are: the rationalisation of cable runs on process lines and machinery; reduced space and weight requirements due to smaller diameters and the combination of power and feedback cores within one cable;and, consequently, installation cost savings.

The first of three basic types of servo cable offered is for DNC motors on frequency converters, an example being the PVC sheathed ÖLFLEX-SERVO®700. This cable comprises four conductors for power and two double screened, twisted pairs of conductors for the NTC resistor and e-brake. An overall screened version-ÖLFLEX-SERVO®700 CY (PVC sheathed, braid screened) - is available for areas requiring improved EMC characteristics.

Secondly, Lapp Cable offers products to enable the control unit of the servo motor to send and receive signals, related to positioning and travel characteristics, to the tacho, brake and pulse transmitters. These cables have an overall tinned copper wire braid screen. ÖLFLEX-SERVO® 710 CY provides servo motor feedback and ÖLFLEX-SERVO® 720 CY is a resolver feedback cable.

Where the application requires a highly flexible cabling solution, such as within power chains, Lapp Cable offers two ÖLFLEX-SERVO-FD® products both with very fine strands (IEC228 Class 6). 760 CP is a polyurethane sheathed, overall screened cable and 770 CP is a polyurethane sheathed, overall braid screened cable with cores twisted into pairs. Polyurethane outer sheathing is recommended for applications that may be subject to contamination by cutting and drilling oils, or where the cables may be affected by abrasion and general wear and tear.

Furthermore, with regards to power supply and feedback, Lapp Cable offer ÖLFLEX-SERVO-FD® 790 CP, designed specifically for the North American market, and halogen-free Cable ÖLFLEX-SERVO-FD® 755 P. The latter has a very small bend radius of just five times the outer diameter, is cold flexible down to minus 30oC and has been tested to a minimum of five million cycles.

Halogen-free cables must be free of chlorine, fluorine and bromine, and are specified because of their increased safety in the event of a fire, and in some circumstances because of the reduced impact upon the environment due to the reduction of harmful pollutants created through the disposal of such products.

The last of the three basic types of servo cable is that for motor supply. For this application - connecting the DNC motors and frequency converters - Lapp Cable has designed a four core cable with conductors from 1.5 to 25sq mm. The cable is also available with an overall braid screen for areas requiring improved EMC characteristics.

Examples of Lapp Cable's motor supply cable include the PVC sheathed with overall screen ÖLFLEX-SERVO® 730 CY, the polyurethane sheathed, overall braid screened, Class 6 fine wire conductor ÖLFLEX-SERVO-FD® 780 CP suitable for highly flexible applications, and ÖLFLEX-SERVO-FD® 785 P that is polyurethane sheathed and TPE insulated for highly flexible applications requiring reduced bend radii.

Lapp's ÖLFLEX-SERVO® cables are used in a number of different applications. The most significant area being servo motor drives and equipment installed in automated manufacturing processes. The main sectors that use this type of technology are: automotive manufacturers, food and drink processors, conveyor and automated machinery manufacturers. The demand for 'hybrid', combined power and data cables, is increasing due to the technical advances being made in machine and processing technology, and the Lapp ÖLFLEX-SERVO® range of products is now being used increasingly for applications outside of the servo motor industry because of the high quality and reliability of the product.

For the specifier looking for cabling solutions to particular problems, such as servo motorcables, Lapp Cable's new Applications Guide "Control cables for all environments" is an indispensable, highly informative tool. For each specific application, the Guide identifies the appropriate Lapp Cable product and details its primary performance (eg, constant flexing for servo motors), its secondary performance (eg, very small bend radius, 5x overall diameter) and capabilities. To obtain a free copy of the Applications Guide, visit the contacts page.

The Lapp Group is a leading global manufacturer of control cables and accessories. In addition to ÖLFLEX® control cables its brands include UNITRONIC® (Data and Bus cables), SKINTOP® (Cable Glands), EPIC® (Cable Connectors), FLEXIMARK® (Cable Marking Systems) and HITRONIC® (Fibre Optic Cables).