The Tata Steel plant in Shotton has eliminated stoppages and cut the downtime of its steel slitting line by around five days a year, following the replacement of its previous multidrive solution, which was proving to be unreliable, with a variable speed drive system from ABB


he multidrive, coordinated through a programmable logic controller (PLC),

adjusts the speed of the uncoiler, slitter, tension unit and recoiler. This ensures correct speed and tension is maintained across the slitting line. The slitting line divides a coiled sheet of metal into smaller widths, before recoiling the sheets at the end of the production line. The previous multidrive solution, from another supplier, proved unreliable as spare parts were difficult to source and some control boards were suffering failures. Repairs were costly due to the labour required to diagnose the fault, source the spare parts and carry out the repair. Alun Davies, engineering manager for Steel Processing at Shotton, says: “The line had been in operation at Shotton for two and a half years, after relocation from another plant. In that time, we suffered four major failures of the drive system and we were losing two to three days production for every failure. “We were concerned that we would

have a major failure that we could not resolve, making the entire line permanently unusable.” The multidrive solution needed to incorporate automatic diameter

support and maintenance. “We agreed upon an Allen Bradley

ControlLogix PLC and an ABB multidrive. We were confident ABB would supply tendering and applications support throughout the lifetime of the project.” ABB supplied Radway with a

calculation as well as accurate tension control at all diameters, to ensure a good quality coil. Diameter is calculated from the ratio between line speed and actual motor speed. There was also a lack of drive safety functions, such as safe torque-off in the previous set up. Jonathan Taylor, director of Radway Control Systems, the system integrator engaged by Tata Steel, says: “The steel company requested that the old system should be replaced by modern equipment on an open platform, avoiding being tied into a single supplier for

An AC multidrive system applied to Tata Steel’s slitting line has

eliminated stoppages, increased production and cut costs

demonstration rig that incorporated a variable speed drive and a motor to test and verify that the PLC could control the drives as expected. Each of the four drives of the ABB multidrive controls an element of the slitter – uncoiler, slitter, tension unit and recoiler. The first three are run under speed control, with the last under tension control. All the drives are run together when processing a steel coil, with the maximum line speed being 300 metres per minute. The PLC is programmed to interface with the drives and provide a speed reference ramp, as well as tension and diameter set points. Data sent back to the PLC allows the

Latest edition to the V-Drive range launched

The V-Drive Basic is the latest addition to the V-Drive range of gearheads joining the V-Drive Advanced and V-Drive Value gearheads. Wittenstein’s worm gearhead family has been given a thorough facelift. Apart from a new look, the gearheads also impress with maximum performance in a very small space - and are fully compatible with the existing series. The newly developed V-Drive Basic complements the V-Drive Advanced and the V-Drive Value, rounding off the extensive and flexible portfolio for all performance ranges. Servo worm gearheads with output shaft and hollow shaft. The gearing of the V- Drive Basic was specifically developed to minimise the noise level in S1 operation. It also convinces with optimal value for money. The V-Drive range of gearheads are suitable for continuous operation with smooth running and synchronisation quality, thanks to superior gearing technology. The V-Drive also boasts maximum economy throughout a life-span of more than 20,000 hours and tailored precision up to 2arc minutes for a variety of applications.

Wittenstein 24 JUNE 2017 | DESIGN SOLUTIONS

company to interrogate the drives the following day in the event of a failure. To improve the safety function of the application, the ABB multidrive solution provides two safety features. The safe stop emergency (SSE) ensures that in an emergency, all drives perform a controlled stop (Category 1 to IEC/EN60204-1), followed by a safe torque-off when the machine has stopped. This means that the machine stops in the shortest possible time, in a controlled manner and is then left in a safe condition. The safe limited speed (SLS) function is used on the uncoiler and recoiler drives only. The drive will initiate the safe torque-off circuit if the safe speed is exceeded. “The major benefit of the new solution

has been the much improved reliability it offers,” says Davies. “We have had no major failures since it was installed. The PLC offers the flexibility we need in programming, allowing us to get useful information such as line metering and coil diameters.”



Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56