Stema Wins Major Contract For Tyre Plant Upgrade

Collaboration between Italian engineering company Stema Service Srl and Control Techniques Italy has resulted in a substantial contract with one of Italy’s leading tyre manufacturing groups. The project, with Unidrive SP AC drives used throughout, has produced energy savings, increased production and resulted in a reduction in maintenance costs.

Stema Service Srl is an engineering company providing automation and process control solutions for companies in the plastics, rubber, iron and steel, marine and galvanic water treatment sectors. Stema Service routinely works with automation systems to improve production throughput, efficiency and reliability. Recently, with increased success in international markets, the company has standardised on suppliers in key areas, including PLC platforms and drives, with Control Techniques selected as its technological partner because of the technical excellence of its product and application experience and the worldwide support from the network of Drive and Applications Centres.

At the tyre manufacturing company, a variety of applications, including rubber mixers and calendar lines, still used DC technologies and solutions. Following extensive study, it was determined that a switch to AC throughout could offer real benefits in terms of energy savings, reduced maintenance and downtime and better throughput and quality. With the maintenance needs of the DC motors eliminated, the company turned its attention to a review of the control system leading to a new approach utilising new PLCs and the introduction of a digital communication bus system based on ethernet.

The company has a mixture of induction and synchronous motors and has been able to standardise on Unidrive SP AC drives from Control Techniques for all of these. Mixers rated at up to 400kW utilise Unidrive SPM modular drives, which, by virtue of their modular configuration – AC/DC modules, plus power modules – deliver greater flexibility for the architecture of the system, as well as minimising back-up spares. On the calendar line, where motor powers vary from just a few kilowatts up to 90kW, Unidrive SP drives are used throughout in open loop, closed loop and brushless servo configurations, depending on the motors employed. All drives were fitted with Ethernet plug-in modules to give a single Ethernet fieldbus.

Some drives feature SM Application modules, bringing a high level of motion control functionality down to the drive level, with the major benefits of less wiring, less chance of interference and enhanced process reliability and performance.

Control Techniques’ Unidrive SP ‘solutions platform’ AC variable speed drive range spans 0.75kW right up to 1.9MW and is configurable into five operating modes – open and closed loop, vector, servo and regenerating mode. A wide range of plug-in option modules provide extra processing power and functionality including extra I/O and field bus connectivity to most industry standard networks and compatibility with most position feedback protocols.

The customer is delighted with the results of this extensive project, with the result that other commissions have followed and Stema Service has become the point of reference for other turnkey projects.

Stema Service has a staff of 15 and offers full service at every stage of a project; basic ngineering, detailed design, testing, installation, commissioning, training, remote assistance (remote access and tele-service) and after-sales support and servicing. The company also has considerable experience in marine applications and is RINI and ABS certified.