Control Techniques’ Unidrive SP AC drives have been used to replace DC technology at an Italian manufacturer of tyres, resulting in energy savings, increased production and a reduction in maintenance costs
Stema Service provides automation and process control solutions for companies in the plastics, rubber, iron and steel, marine and galvanic water treatment sectors, and 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. In this area, Control Techniques has been selected as its technological partner for a number of reasons including product quality, application experience and the worldwide support from the network of Drive and Applications Centres.
Some drives feature SM-Applications modules, bringing a high level of motion control functionality down to the drive level, meaning less wiring and less chance of interference
Collaboration between the two companies has resulted in a contract with one of Italy’s tyre manufacturing groups. Various applications within the tyre manufacturing process, including rubber mixers and calendar lines, were still using DC technologies and solutions. A study determined that a switch to AC throughout could offer 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, resulting in the use of 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 use 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, which brings motion control functionality down to the drive level. This means 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 up to 1.9MW and is configurable into five operating modes – open and closed loop, vector, servo and regenerating mode. A 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 tyre manufacturer is pleased with the results of this project, with other commissions following, and Stema Service has become the point of reference for other turnkey projects.