A Lenze SMV frequency inverter has solved a breakage problem for a European rope manufacturer. Prior to installation of the SMV inverters, the 10-station winding machine used in the production of polyester rope, caused major headaches with poor product quality and the unplanned downtime needed to repair breakages.  Retrofitting the drives has achieved constant smooth tension in the rope strands, even during speed changes, and elimination of rope breaks.

The plant operator, located in Poland, turned to the local Lenze agency with a requirement for an integrated solution that would cut out the downtime, eliminate manual adjustments and produce a high quality product that is evenly wound. The retrofit solution provided was based on the SMV inverter, a high performance sensorless vector drive ideal for dynamic speed control. In this case, the IP31 version was used for mounting in a cabinet, but the SMV is also available with IP65 enclosure for decentralised installation.

Each of the 10 stations has a dancer roll and position signals from there are input to the integrated PID processor in the drive. Here the processor compares actual signals with a set point and finely adjusts the pull speed to compensate for any errors. By doing so the inverter maintains a steady tension in the rope strand resulting in wound reels of rope that are consistent in shape, an obvious sign of high quality. Furthermore the steady tension has eliminated rope strand breakages and the expensive downtime associated with them.

The SMV range of Lenze inverters is available for single phase input 0.37 to 2.2kW and three phase 0.37 to 45kW. Availability is from stock with communication options such as CANopen, PROFIBUS, EtherNet/IP and DeviceNet. All SMV inverters feature a plug-in memory chip that holds all the drive parameters meaning that reprogramming can be done in seconds, even without power. The drives have approvals for use worldwide.


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