Inverters with PID control retrofitted to rope-winding machine

Lenze SMV frequency inverters have demonstrated their capacity for the fast dynamic torque response on a ten-station winding machine used in the production of polyester rope. Prior to installation of the SMV inverters, the winding machine suffered major problems with poor product quality and unplanned downtime needed to repair breakages. Retrofitting the drives has achieved constant smooth tension in the rope strands, even during speed changes, and has eliminated rope breaks.

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

Integrated PID control

Each of the ten stations has a dancer roll, from which position signals are fed 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 - which is an obvious sign of high quality. Furthermore, the steady tension has eliminated rope strand breakages and the associated costly downtime.

The Lenze SMV inverters are 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.

Follow the links for more information about the IP31 SMV inverters and IP65 SMV inverters.