Lenze has supplied a full package of inverters, geared motors and control connections to Sellers Engineers for its finishing machinery for the carpet and textile industries

Known throughout the world for its machine quality and reliability, Sellers Engineers of Huddersfield manufactures an extensive range of finishing machinery for the carpet and textile industries. Recently, the performance of one of its products, a carpet-shearing machine that trims the carpet surface, has been improved greatly by the inclusion of Lenze equipment.
Chosen for their proven reliability and performance on similar textile machinery, Lenze supplied a full package of inverters, geared motors and control connections, which not only contributed towards reducing the amount of hardware required to operate the machine, but also helped reduce and simplify maintenance operations.
One company to take advantage of the benefits offered by the innovative design of Sellers' carpet shearing machine is Westex Carpets in Cleckheaton.

Westex Carpets manufactures carpets in widths of four or five metres, that are then fed into the shearing machine to achieve a clean and uniform finish.

The shearing machine has two cutter heads fitted with eight Lenze drives, with control signals delivered from an Alan Bradley PLC using Profibus.

The machine also features two shearing cylinders, each driven by 7.5kW Lenze inverters and helical geared motors from the Lenze G-motion range mounted directly onto the rollers.
The inverters are fitted with an optional module to accept the Profibus line speed and tension signals.

The gearboxes dispense with the need for chain drives and belt connections, offering quick and easy maintenance The cutter head assemblies also encompass driven rollers that control carpet tension.

Load cells sending a 0-10 volt signal directly to Lenze vector inverters measure this tension, while the inverters also take into account information relating to line speed and tension set point.

The PID controller in the vector inverter adjusts the master line speed by up to 5% according to the load cell signal.

Additional drives in the cutter head control brushes and positioning.

The key advantage of the Sellers machine design is that both speed and tension control is achieved in the Lenze vector inverters with built-in PID control and two positions for plug-in modules.

The first module handles the Profibus signals from the PLC, while the second plug in module provides expanded I/O to take in the speed, tension set point and load cells signals, with extra capacity in reserve.

With no separate tension controllers required, the Lenze equipment helps save on panel space and simplify the control system.

The accuracy of this integrated system also means that higher line speeds and better tension control result in a consistently superior carpet finish.

This article was originally published on Engineeringtalk on 8 October 2001 at 8.00am (UK)