Stema wins tyre plant upgrade contract
A 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.” According to the companies, 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. In the case of the unnamed 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-Applications 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.