SKiiPRACKTM Versatile high power inverter platform 150 kVA – 3 MVA High power den sity > 12 kVA/litre With SKiiP ® 1200V&1700Vwater-cooled Configurable individual phase assemblies AC connections at front or rear United Kingdom, Hertford +44 1992 584677 info.skuk@semikron.com www.semikron.co.uk
UK industry ‘is not managing its electric motors effectively’ NEWS ABB IS WARNING that much of British industry is not managing its electric motors correctly <strong>and</strong> is rewinding too many old motors, rather than replacing them with more effi<strong>cient</strong> new models. This is costing it millions of pounds in terms of unnecessary downtime, repairs <strong>and</strong> energy usage. ABB says that the problem is highlighted by the fact that the motor repairs industry in the UK is now worth more than twice as much as the £70m market for new low-voltage industrial motors. While acknowledging that mechanical repairs, such as bearings <strong>and</strong> shafts, will always be needed, ABB argues that too many motors are being rewound automatically. Steve Ruddell, manager of ABB’s UK motors business, believes that the reason for so many rewinds <strong>and</strong> premature failures is a lack of awareness among end-users of the need to create motor management plans. “It appears much easier when a motor fails to have someone collect it, rewind it <strong>and</strong> reinstall it,” he says. “But what if this is a critical, continuous-process application? Taking it offline could cost hundreds of pounds per hour. “Some industries are better than others,” he adds. “The pulp <strong>and</strong> paper sector, for example, tends to have a policy that if any motor is running for more than 4,000 hours per year, it will be replaced automatically by a high-efficiency motor at the point of electrical failure. Any motor below 75kW, irrespective of running hours, is automatically replaced at point of electrical failure. “No one should be making inferior motors today,” Ruddell continues. “The technology <strong>and</strong> materials used by today’s motors gives them an expected lifespan in excess of 20 years. They should be durable <strong>and</strong> highly <strong>reliable</strong>. Yet many repairers have motors Rudell: a few small steps can lead to significant leaps less than five years old on their benches for rewind, alongside older motors having had multiple rewinds. “It is analogous to the car industry,” he suggests. “Today you rarely see a rusty car <strong>and</strong> very rarely see cars breaking down. Technology has improved the reliability <strong>and</strong> lifespan of cars, <strong>and</strong> the same is true for lowvoltage motors.” To encourage better motor management practices, ABB has launched a scheme called MotorAdvantage, designed to reveal the true cost to a company of running its electric motors. The scheme includes a site visit by a motor engineer who assesses the installed motor base <strong>and</strong> identifies up to five motor-driven applications with the potential for further analysis. The scheme also assesses the user’s motor failure policy <strong>and</strong> its financial implications, identifies potential improvements to this policy <strong>and</strong> stockholding, <strong>and</strong> determines the energy use of the current installation. According to Ruddell, a motor management plan can pay for itself within weeks, if not days, by preventing unplanned outages. “MotorAdvantage aims to elevate motors from being a hidden asset, with an out-of-sight, out-of-mind maintenance approach, to an asset that can earn you real financial rewards immediately,” he says. “Our job is to re-educate the market into the enormous savings that they could be making from this asset. “We want to show industry that a few small steps can lead to significant leaps in a plant or process profitability,” Ruddell continues. “Normally motor management plans are overly ambitious, trying to assess every single motor on a plant. “If it is more cost-effective to rewind a motor, we will advise of that action,” Ruddell emphasises. “Our role is no longer just about making motors – we need to help companies manage the ones they have in place more effectively.” www.abb.co.uk/energy Stuxnet virus targets Vacon inverters THE LATEST REVELATIONS about the Stuxnet virus suggest that it contains code that can alter the operation of frequency inverters from the Finnish drives-maker Vacon <strong>and</strong> from an Iranian supplier called Fararo Paya, thus varying the speeds of motors they are controlling. Eric Chien from the anti-virus specialist Symantec says that although his company had previously discovered that Stuxnet modifies PLC code in a potential act of sabotage, it had not been able to determine its exact purpose or target. However, its latest findings indicate that Stuxnet targets industrial control systems containing drives from at least one of the two vendors, as well as the previously identified Siemens S7-300 CPUs <strong>and</strong> CP-342-5 Profibus modules. The virus requires the drives to be operating at the relatively high frequency of 807–1,210Hz. When Stuxnet finds the specified inverters operating at these speeds, it changes their output frequencies <strong>and</strong> thus the speed of the motors they control for short intervals spread over periods of months, thus disrupting the processes being controlled. Chien points out that drives with outputs above 600Hz are regulated for export by the US Nuclear Regulatory Commission because they can be used for uranium enrichment. Earlier reports have suggested that Stuxnet might be targeting centrifuges used by Iran as part of its nuclear programme. If the drives continue to run at high speeds for a period of time (about 13 days), Stuxnet hijacks the PLC code <strong>and</strong> begins modifying the drives’ behaviour. Over a period of months, it changes their output frequencies to 1,410Hz for short periods, <strong>and</strong> then to 2Hz <strong>and</strong> 1,064Hz. This “essentially sabotages the automation system from operating properly,” says Chien. Other parameters may also change, causing unexpected effects. Details of Symantec’s latest findings are contained in an updated version of its White Paper on Stuxnet. It has also created a YouTube video demonstrating how Stuxnet can hijack PLCs. http://goo.gl/YwTZC www.drives.co.uk November/December 2010 3
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