VARIABLE-SPEED DRIVES n machine use. Each machine talks to a main PLC that shuts off the drives when they are not needed. “We removed the 75kW fan and motor but kept the existing 37kW one, then added two rated at 18.5kW and one at 22kW,”Cobb reports. “We matched these with four new Altivar ATV630 process drives, with automatic start-stop functions linked from the printing and binding machines to the PLC via the factory network. “I was very insistent about was choosing Schneider Electric’s VSDs,” he adds “That’s because I’m confident in the reliability of the drives and because they always provide a quick response, whether I’m asking a straightforward or complex question. A further benefit is that the drives provide the flexibility to adjust settings and parameters through the HMI.” The new cabinets were installed alongside the existing equipment to minimise downtime and ensure that there was no interruption to Warners’printing schedule. Paramount replaced the ductwork completely over a weekend to avoid the need for a major outage. This was a substantial undertaking due to the scale of the ducting. Warners and Schneider Electric now maintain a close working relationship, with local account managers always on hand to source specialist engineers or spare parts if anything goes wrong. “With a project like this, it’s about asking the right questions to identify what the customer needs,” says, Schneider’s industrial specification engineer, Dave Whitehouse. Reflecting on the final commissioning, Cobb says: “The pressure was on to deliver what I had promised in terms of energy savings. So, when I completed final testing, I was relieved to have met the expectations for the scheme, and to have achieved the target energy savings.” “By right-sizing the system and adding automation, we have cut the dry waste extraction system’s annual energy bill by 62%,” he reports. “We’ve also added extra benefits of flexibility, reliability and low maintenance requirements. And we no longer need to constantly remind our operators to switch off the fans because that happens automatically when they switch off the machines.” n Fig 1: In the old scheme, two large motors each served three machines Fig 2: The new decentralised scheme is based on four right-sized motors serving groups of machines
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