Drives, motors and controls

  • Drives & Controls - Delivering energy understanding to the top table

    Speak of deploying widespread AC inverter technology, or calculating cube law considerations for a plant's fans and pumps and the average finance director would keel over. However, as GAMBICA's variable speed drives group argues, until such topics are understood at the top table, industry will fail to maximise potential energy efficiencies

    In most developed countries, industry accounts for about half the electricity consumed. Of this industrial consumption, two thirds is typically used in powering electric motors. For this reason, the control of motors must be placed high on any energy efficiency agenda. Yet, because motor control involves highly technical issues, the overwhelming majority of boards of directors and senior business managers continue to focus energy efficiency attention on readily understood areas such as insulating building fabric and reducing lighting consumption.

    For many, energy measures revolve around the consideration of thermal issues in the building fabric with remedies such as insulation, glazing, and heat loss countermeasures. These are really only passive countermeasures that compensate for energy loss rather than the active control of the energy deployed.

    Under the Kyoto Protocol industrialised countries have agreed to reduce their collective emissions of greenhouse gases by 5.2% by 2008-2012 compared to the year 1990 (however, compared to the emissions levels expected by 2012 prior to the Protocol, this limitation represents a 29% cut). The target in Europe is an 8% reduction overall with a target for CO2 emissions to fall by 20% by 2020.

    The cost of an electric motor can be very deceptive; in particular, the annual energy cost to run the motor can be up to ten times its purchase price. Indeed, the running costs of a fully loaded motor operating at 50Hz can range from over £1,000 a year for a 2.2 kW motor to over £18,000 a year for a 37 kW one. Consider that, for example, a typical 11kW AC induction motor, that can be purchased these days for as little as £300, could cost as much as £30,000 in electricity consumed over a 10 year lifetime.

    Fit a variable speed drive and simply by slowing the motor by 20% the energy bill is halved. About 105TW of electricity is consumed by British industry each year. It is estimated that two thirds of that is consumed powering electric motors; and of those motors about three quarters of them power fans, pumps or compressors in continuous duty variable torque applications. It is these variable torque applications where the greatest savings can be made from VSDs.

    In other words, if every fan, pump and compressor motor was equipped with a VSD and had a 20% reduction in speed, the total consumption would fall by about 26TW per annum. Put another way, the savings would enable the closure of the UK's largest coal fired power station, saving 20 million tonnes of CO2 per annum. Even more dramatic to consider is that this figure effectively means that the CO2 emission attributable to  3.1 million homes would be negated. In other words, the whole of Greater Manchester and Birmingham would be rendered carbon neutral!

    If the targets of those nations compliant with the Kyoto Protocol are to be met, greater attention must be placed on broader energy efficiency regimes. These have to include motor speed control.

    Most of the bodies charged by government with communicating and effecting change in the approach to energy consumption are naturally focussed on conservation in the broadest public arena. For this reason, the public relations and other promotion has been almost exclusively targeted at the general public and on measures such as insulation, heating and lighting reduction. This is true even of the respected Carbon Trust and Energy Saving Trust in the UK. However, with ambitious national carbon reduction targets and current consumption trends failing to meet the rate of decrease needed indicates that the UK will fall drastically short within the 2020 deadline. Bodies such as Gambica, which represents most of the significant motor speed control manufacturers, know that more must be done.

    That government may impose further levies, legislation or penalties relating to energy use is speculation, but as the 2020 deadline looms, it remains a possibility. Against this backdrop, is the almost exponential rise in energy prices that are directly impacting on industry, commerce and consumers by its significant and proportionate affect on costs.
    In the simplest terms there are a number of things business can do: ignore energy issues completely and either pass on costs as increased prices or accept continuously reducing margins (rather than invest in energy efficiencies); take passive measures such as installing energy saving luminaires, improving insulation; take active energy initiatives and address all aspects of consumption.

    Hence, we return to the topic of motor control. This for industry, commerce and large commercial buildings represents low hanging fruit in terms of making substantial energy savings. In many respects fitting motor speed controls is like changing to energy saving light bulbs in the home - but with on-going automatic savings.

    First, a quick physics lesson
    Consider that billions of electric motors are in daily (often continuous use) every day. In most countries, fewer than 10% of the motors have any form of control. In continuous duty applications such as powering fans, pumps and compressors, it is possible to effect incredible savings by reducing the motor speed by a very small amount. This is because in such applications, the fundamental physical laws governing centrifugal fans and pumps also preside over the potential savings that can be achieved. In laws of physics, power is consumed as a cube of output. Indeed, affinity laws dictate that while motor torque varies with the speed squared, power varies with the speed cubed. Hence, the cube law impacts greatly the energy efficiency in such equipment.

    On loads of this type any speed reduction will save large amounts of energy (that is, a 20% speed reduction will result in a 50% power saving). Remember, torque varies with the speed squared, power with the speed cubed. This means that variable torque loads, such as fans and pumps offer the greatest potential for energy saving.
     
    Culture gaps inhibit industrial energy conservation
    Why there has not yet been a huge uptake of motor speed controls lies largely with ignorance of the technology and ambiguity within industry over who owns the task of implementing energy efficiency. To explain this statement more clearly, in a manufacturing plant for example, the plant engineers are often acutely aware of the energy efficiency benefits of installing variable speed drives (VSDs) to AC motors. In the boardroom, managers may be alert to the need to economise on energy for any number of reasons: escalating fuel bills; corporate social conscience; or even just because it's good marketing sense to be seen to be green. The problem is plant engineers are never measured on their ability to save energy; while directors and managers are unaware their plant engineers could do so. It is a simplistic view, but one borne out by evidence throughout manufacturing industries.
    Energy intensive industries such as metals manufacturing, glass and plastics processing and food and beverage production understand the need for energy management because their processes involve great amounts of heat. These businesses have traditionally sought ways to maximise their return on investment from the energy used in their primary processes. However, even these energy aware businesses often fail to realise how much more can be saved through building controls and a company wide energy policy.

    Of far greater significance overall is the use of variable speed drives in a broad range of processes.

    While in many countries industrial energy use has now been slightly outweighed by that consumed by commercial and residential buildings, it is a fact that industry consumes huge amounts of electrical power. About two thirds of that is typically consumed powering electric motors. Of these, an overwhelming majority can be made significantly more energy efficient by controlling their switching on and off or by controlling their speed.

    This is a relatively simple task of equipment retrofitting, yet it is clear that most manufacturing and process plants fail to take the step. The reason is often because those that control the costs of an industrial operation are not communicating with those charged with the management of the production processes.

    For example, if a painting plant uses hundreds of AC motors on fans, pumps and compressors (continuous duty applications) it could readily benefit from the use of variable speed drives. However, while the plant manager, as an engineer, understands this, he or she is invariable responsible only for improving productivity or output and not for the overhead costs. Higher management is concerned with paying the overheads but remains unaware that such a saving could be made because it is never on the agenda in engineering meetings.

    In industry, senior management and plant engineers must learn to talk if an holistic and comprehensive energy efficiency policy is to be achieved. In no other sector is the communication gap wider, than between those charged with making energy decisions and engineers in industry who know how energy can be saved.

  • Competitiveness boosted by maximising drives’ reliability

    ABB's three-tiered variable speed drives service programme is said to help users prevent downtime and production loss.

    The three levels of service - DrivesAdvantage, DrivesActive and DrivesActive+ - enable each customer to choose from a range of services that can be tailored to suit their needs and budget precisely.

    The portfolio ranges from the installation and commissioning of new drives, through maintenance and spares support during service, to replacing products as they reach the end of their working lives.

    A brochure describing DrivesActiveand DrivesActive+is available free from the BrochureLine, tel 0800 783 7491. Alternatively order online at www.abb.co.uk/energy.

  • Drives key for machine OEM

    An Indian manufacturer of biscuit production machinery is using ABB drives to ensure its customers can produce high quality, consistent biscuits.

    Located just outside Mumbai, Bake-O Nomic is one of India's leading OEMs of biscuit manufacturing lines, producing three fully automated biscuit production plants per year for sale mainly to Nigeria and other African markets.

    Because biscuit making is a continuous process, with a number of stages feeding into each other, it is important that each stage is controlled at its own appropriate speed. All the machines, such as biscuit cutting, forming, oven and cooling conveyors are linked to each other, accepting materials or part processed biscuits and passing them on to the next stage.

    As each type of biscuit has a different baking time, the company needs a reliable and energy efficient way to vary the speed of the different parts of the process.  An example is mixing, which is done in two stages. Shortenings and sugar are mixed at high speed and subsequently flour is added and mixed at a slow speed.

    One of the most reliable and energy efficient ways to control this sort of production line is through the use of low voltage AC drives.

    Praful Dattaram Kale, owner of Bake-O Nomic, says: "We chose ABB because of its reputation in the market. ABB is renowned as a reliable supplier with a broad product range. Also, as ABB is a global player, we can benefit from its extensive service network. Should any of our equipment need repairing or maintaining as a result of a drive malfunction, then it can be fixed locally and efficiently."

    The drives are used primarily on biscuit cutting and forming machines, mixers, ovens and conveyors. About 20 drives are used in a single biscuit making line, most of them below 5.5kW, although for mixers, drives as large as 30 kW can be used. Above 0.75kW, ABB standard drives are used, while below this power ABB machinery drives are used.

    Most are manually controlled individually, a method preferred by the company's customers, who need a fine speed variation depending on the requirements of the type of biscuits being produced.

    Bake-O Nomic has used AC drives for energy saving, both electricity and fuel, in some blower applications in its own biscuit making plant set up in Nashik.

  • Drives & controls - Making redundancy redundant

    Modern control systems are invariably designed with safety as a prime requirement. Often this can add significantly to the cost, particularly where high-power contactors have to be duplicated to provide redundant operation. Fortunately, there's now a better approach, as Moeller Electric's Steve Rickard explains

    Almost every control panel incorporates motor starters and there can be no doubt about it, when a safety relay operates or an emergency stop button is pressed, the motors controlled by those starters have to stop.

    It's easy enough, of course, to design the control circuits to behave in this way, but what happens if there is a component failure? In particular, what happens if a contactor has welded closed? The answer is that, unless further measures have been taken, the motor controlled by the welded contactor will continue to run.

    Clearly, this very dangerous state of affairs cannot be tolerated, particularly as welding is a relative common failure mode for contactors, especially those that have reached the end of their service lives.

    The usual solution is to incorporate two identical contactors in series in the starter circuit which meets the requirements of Safety Category 3 and 4. The risk of both contactors welding simultaneously is unlikely, so at least one of the contactors will always open when required to do so, and the motor will be safely stopped.

    While this approach of using redundant contactors is effective and widely used, it does have several drawbacks. The first is cost. While small contactors are relatively inexpensive, their larger counterparts certainly are not. So, with a 100kW drive, for example, using a second redundant contactor adds significantly to the overall cost of the control system. The next drawback is panel space. High current contactors take up a lot of panel space, and not only is panel space expensive, there is often insufficient room available on site to allow large panels to be accommodated. Finally, duplicated contactors increases the amount of heat generated within the panel, because of the losses from the coil and main contact circuits.

    To address these issues, Moeller Electric has pioneered the development and introduction of a new type of control component - the contactor monitoring relay, a device which is both compact and inexpensive.

    The principle of operation of this innovative device is easy to state. It simply compares the state of the main contacts of a contactor with the voltage that's being applied to the coil. If the coil is de-energised but the main contacts are still closed, the output relay of the contactor monitoring device operates, opening a set of contacts that can, for example, be used to trip an undervoltage release on the circuit breaker protecting the motor circuit. In this way, it's clear that, even if the contactor welds, the motor will still be brought to a stop safely. The need to use a duplicate contactor to ensure safe operation is, therefore, eliminated.

    While the principle of operation of the contactor monitoring device may be simple to state, however, designing a practical product is a little more challenging. For example, what is the best way to monitor the main contacts of the contactor?

    The solution adopted by Moeller Electric is for the monitoring device to look at the state of an auxiliary contact on the contactor. Not all auxiliaries are guaranteed to accurately reflect the state of the main contacts, however, especially when the contactor is faulty. The auxiliary used for this function must, therefore, meet the requirements for a mirror contact, as defined in the IEC EN 60947 Annex F.

    Essentially, these requirements state that a mirror contact on a contactor is a normally closed contact that can only ever close if all of the main contacts have opened. All N/C contacts on DILM and DILH contactors from Moeller Electric meet this requirement. That's not quite the end of the story, however, as we need to consider what happens if the auxiliary contact itself welds closed. This is very unlikely, but by no means impossible. The solution here is to compare the state of the N/C auxiliary with an N/O auxiliary in the same contact block. Provided that the contacts are positively driven - a condition once again met by the standard auxiliaries used with Moeller Electric contactors - they can never be closed at the same time unless a fault has occurred.

    By monitoring a positively driven N/O auxiliary as well as the N/C mirror contact, the contactor monitoring relay can, therefore, immediately detect problems with the mirror contact and generate an output to trip the drive.

    As this discussion shows, the characteristics of the contactor and of its auxiliary contacts have a critical bearing on the operation of the contact monitoring device. For this reason, Moeller Electric provides details of approved product combinations that will ensure the appropriate levels of safety are achieved.

    With these combinations, the operation of the contactor, the contactor monitoring device and the motor protective circuit breaker complies with the requirements of EN ISO 13849 for Performance Level e, provided the number of switching operations of the contactor does not exceed 350,400 per year, and that the number of switching operations of the protective device does not exceed 1,095 per year.

    In the calculation of the overall performance level for the control system, however, the safety components upstream of the motor starter also have to be taken into account. When this is done, the result is that, with the aid of the contactor monitoring device, control systems that overall meet the requirements for Performance Level d can be readily implemented.

    Small, easy to use and cost effective, contactor monitoring devices are a very attractive and convenient alternative to the adoption of redundant contactor designs in control systems. They save money and space, as well as reducing the amount of heat generated within the panel, all without compromising the level of safety achieved by the overall system.

    With contactor monitoring devices offering so many benefits, surely it has to be time to make redundant contactors redundant?

  • Drives & controls - Drive to reduce energy pays dividends for PET bottle producer

    Rockwell Automation has worked with Proplas International to help Europe's leading supplier of rigid plastic packaging to reduce its energy costs by £71,000 a year, with a payback period estimated at just 14 months

    ONE?OF Europe's leading suppliers of rigid plastic packaging is reaping the benefits of an energy saving retrofit on 13 injection-stretch-blow moulding machines. Engineering services provider Proplas International fitted 13 of the packaging specialist's PET bottle and jar moulding machines with Rockwell Automation's Allen-Bradley PowerFlex700 variable speed drives, helping to reduce energy consumption by over 27 percent.

    From its base in Burnley, Lancashire, Proplas International has built a reputation for helping industries to become more efficient - something which all companies will recognise as being vital in today's increasingly competitive market place. Amongst other areas, the company has become widely known for its energy saving projects, with a particular focus in injection moulding machines of all types where Proplas is a recognised leader in saving energy.
    In a recent project, Proplas fitted Allen-Bradley PowerFlex 700 drives to 13 injection-stretch-blow-moulding machines at Europe's leading supplier of rigid plastic packaging. The machines produce a range of bottles and wide-mouth jars in Polyethylene-Terephthalate (PET) for the food and drinks industry - containers that are used by a range of industry-leading manufacturers as well as by various supermarkets for their own-brand food and drink products.

    The injection-stretch-blow-moulding process is used because of its capability to produce high quality containers. In the process, molten polymer first flows into the injection cavity to produce the desired preform shape. A period of conditioning at a set temperature follows, after which the preform is ready for stretching and blowing into the finished shape. The preform is transferred to the blowmould area, and the mould closes. A stretch rod is introduced to stretch the preform lengthways, whilst differential air pressure is used to blow the preform out to the shape of the mould. Finally, after a set cooling time, the mould opens and the finished container is removed. In practice, the four stages are carried out concurrently with a revolving carousel of moulds.

    Proplas director Stephen Anderson comments: "The machines were being driven by hydraulic pumps, with their motors set at a constant speed that would cater for the maximum hydraulic demand - the periods in the process where the moulds are opening and closing. But this is an inefficient process, since the energy usage remains constant (and high) while the actual power demand varies."

    The Proplas solution was to fit variable speed drives to the pump motors, operating at two preset speeds - a higher speed during the maximum hydraulic demand when the moulds are opening and closing, and a lower speed during the periods of reduced demand.

    "We performed a number of tests with the company to demonstrate the potential, and convinced them that there could be major energy reductions and associated cost savings," said Anderson. "As a result, we were asked to retrofit a drives solution to 13 of the company's injection-stretch-blow-mould machines."

    The retrofit was built around 13 Allen-Bradley PowerFlex 700 drives, with each drive connected to an Allen-Bradley Pico micro PLC to provide the simple sequencing logic.

    "The available torque was a key issue in this application, because the profile is characterised by spikes in the torque demand that can cause many other drives to trip," says Anderson. "The PowerFlex drives delivered the same torque in the actual application that was promised on the datasheet, and in this case that capability allowed us to downsize to a lower power product without any fear of it tripping out or the motor stalling, helping deliver further energy savings for the customer."

    For the customer, all this has meant some substantial energy savings. The power usage of each machine before the modification was 40kW, but with the help of the drives retrofit this has been reduced by 11kW. With every kilowatt equating to around £500 in energy costs, the project is estimated to be saving the customer over £5000 on every machine, with an estimated payback period of just 14 months.

  • Customised drives now available online

    Danfoss Drives and its partners now offer online ordering of the VLT Micro Drive. Customers can order customised drives through a centralised platform and take delivery from their local distributor. The benefits include minimum processing time for orders, direct follow-up and the shortest possible delivery time.

    The new web site, at www.vltmicro.co.uk, allows users to customise the drive, select their local distributor and pay for the order using PayPal or major credit cards.

    "It's simple, easy and fast" says Anthony Pickering, senior sales director at Danfoss Drives. "We wanted a platform that allows the customer application to be up and running in the shortest possible time"

  • Drives and motors catalogue highlights new products

    The 2009 edition of ABB's drives and motors catalogue is now available for end-users, system integrators and Original Equipment Manufacturers (OEMs). The 48 page catalogue is free and can by downloaded directly from www.abb.co.uk/energy or a hard copy is available from freephone 0800 783 7491.
    The catalogue provides technical details of ABB's range of low voltage AC drives from 0.18 to 2,800 kW and motors from 0.06 to 710 kW. It also presents ABB's range of DC and medium voltage AC drives. Easy-to-use tables give ordering data, dimensions, options and electrical details for most products, together with prices for 2009.
    ABB Limited
    Tel: 01925 741 111
    www.abb.co.uk/energy

  • Drives & Controls - Could a basic energy audit prove the saviour of UK industry?

    As uncertainty surrounding the future of energy prices grows, and firms are pressured into attempting to reduce their carbon footprint, there has never been a better time for industry to consider the merits of variable speed drives and high efficiency motors. Manufacturer ABB has developed an energy audit that quickly and accurately pinpoints the potential savings in an industrial plant

    A variable  speed drive (VSD) and electric motor combination, when used to control the speed of pumps and fans, can reduce the energy bill of these applications by some 70% with a payback in less than 12 months.

    And yet a survey of British manufacturing managers with engineering roles has revealed that they do not regard VSDs as being the best way of cutting their companies' energy bills. The survey, conducted for ABB, reveals the 67 engineering managers surveyed placed VSDs at the bottom of a list of the ten most effective measures for cutting energy bills.

    Joint top of the list were negotiating better prices with their company's existing energy suppliers and fixing compressed air leaks. ABB had expected the survey to show significant differences in attitude between the financial and engineering managers, with the latter appreciating the role that high-efficiency technologies could play in cutting energy bills.
    The financial mangers believe that clamping down on visible waste, such as inefficient lighting and compressed air leaks, is important. Investing in equipment that makes industrial processes more efficient came at the bottom of their list.

    "This list is back to front," says Ruddell. "Making industrial processes more efficient can save much more than the other methods, but financial managers are simply unaware of the savings they can make. Most companies can save thousands of pounds worth of electricity and some can even save hundreds of thousands of pounds, often at comparatively low cost. Changing electricity suppliers is not going to make much difference at all in a market where prices rise across the board," he adds. "In addition, this does nothing to reduce the company's carbon footprint, which also ought to be a priority."

    ABB is in the vanguard of energy promotion, launching, in 2004, its award winning 6-step energy saving plan.

    6-step energy saving plan
    The plan documents six basic steps towards understanding and planning an energy saving campaign.
    Step 1. The facts:
    Gives an insight into the latest thinking on the Climate Change Levy and UK government actions to encourage greater energy savings.
    Step 2. The savings:
    In just half-a-day, an energy audit can help identify the applications that offer the best energy saving opportunities.
    Step 3. The finance:
    Offers information on how to finance a drive purchase while still benefiting from the government's Enhanced Capital Allowance.
    Step 4. The products:
    Guides the end-user through selecting the best motors and VSDs for specific applications.
    Step 5. The proof:
    Gives examples showing how industry has benefited from using VSDs and motors.
    Step 6. The action:
    Gives advice and further contact information at ABB and its extensive UK channel partner network.

    Energy saving audit
    At the heart of the 6-step plan is ABB's energy audit. On a typical industrial site with a £150,000 annual electricity bill, £100,000 will be spent on running motors. For example, are any motors or fans running on full power all the time when they could be driven by demand?
    The answer is a professional energy audit. Undertaken by a trained engineer, an energy audit will identify those applications that would most benefit from the introduction of VSDs. The results, based on measured data from the application, will help a user target their investment so that it produces the highest possible savings and gives the best return. ABB has devised a very simple and methodical energy audit that presents the customers with hard, compelling facts about the energy they can save.

    1. Outlining the scope of supply
    During an initial meeting the audit engineer takes a look at the inventory of motors contained within a plant.

    Energy surveys are most suitable for processes involving motors of 11kW or higher, used on large pumps and fans. This is where the savings from a VSD really start to look good compared to the investment cost. Often payback times of two years and below and sometimes under one year, can be achieved. ABB meets the end-user and outlines the benefits of the audit in detail, together with any assistance the end-user might need.

    2. Collecting the data
    The data collection phase is an active phase. It involves an on-site audit with selected fans and pumps, to determine operating parameters such as voltage, current and power factor and the energy being used. This stage will usually be performed over seven days to gain a complete picture of the plant's typical energy use. The end-users own staff may become involved at this stage although different auditors have different approaches.

    3. Analysing the data
    Following the collection of the data, the findings will be analysed and potential savings identified using dedicated software. The findings will be methodically presented - often tables or graphs will be created to help see where savings are likely to arise.

    4. Recommendations
    The action plan will then be prepared, usually comprising an Executive Summary and a detailed engineer's report, highlighting applications that can save the most. The figures will normally be translated into monthly savings, and there will be detailed recommendations for fitting particular VSDs or motors. The report should also clearly show the expected payback time on fitting new equipment.

    5. Implementation
    While not strictly part of the audit the aim is that the recommendations should be fully implemented. Once new equipment is fitted it is normal to track the actual savings against the predictions shown in the report. This will also help justify the investment in VSDs.

    6. Benefits
    An energy audit carried out by ABB or one of its channel partners brings the following benefits:
    - Clearly identified energy savings
    - Complete audit results and energy saving calculations 
    - History of other audits and associated energy savings
    - Proposed payback times 
    - Degree of customer training given as part of the process
    There are also other aspects to consider, for example whether financial options are available and if your supplier offers a replacement drive scheme.

    Carbon emissions calculator
    More recently, ABB has added another tool to its 6-step energy saving plan. As carbon emissions take a higher priority on company boardroom agenda's, ABB has developed a simple to use and understand carbon footprint calculator.

    The user enters a motor's rating, and the calculator shows the energy savings in kWh, as well as the monetary savings, the cost of a suitable drive, and the payback time.
    "Quantifying the carbon footprint helps organisations to manage their footprint and reduce emissions over time," says Ruddell. "But motor energy use is frequently overlooked, despite being the largest are of electricity use in industry.
    The carbon calculator can be accessed via www.abb.co.uk/energy

    Corus Strip Products
    It was just such an energy audit that produced spectacular benefits for a steel maker in Port Talbot South Wales, saving £1m on its annual energy bill.

    Corus is one of the biggest steel making companies in the UK with annual output of five million tones. Energy was Corus' second biggest cost after raw materials and with energy prices rising year on year it was important that energy expenditure was minimised.
    As part of a plant-wide energy saving programme, 24 ABB industrial drives, ranging from 140 to 400 kW, where installed to control pumps on the hot strip and cold mills, plus three fans on the coke ovens. The cost of the drives about £1m; the whole project including pumps, cabling etc. is around £2.5m.

    "The pump and fan motors were oversized and running longer hours than necessary," Says Guy Simms, leader of the Energy Optimisation team at Corus Strip Products. "But with the ABB drives we are now installing, we can fine-tune the applications reducing energy consumption."

    McKechnie Automotive and Engineered Plastics
    Following an energy audit at McKechnie, a manufacturer of engineered plastic assemblies ABB was able to reduce energy costs by over 30%.

    The plastics manufacturer based in Pickering brought in Halcyon Drives, an ABB Drives Alliance partner to improve the efficiency of their injection moulding machine. Typically most injection machines are hydraulically operated and often waste between 20 and 50 % of the electrical power they consume. By adding a variable speed drive it is possible to control the speed of the pump motor to deliver the precise amount of electricity needed for each sequence in the injection moulding cycle.

    "By introducing variable speed drives our energy cost has been significantly reduced" Says Rob Howlett senior process engineer for McKechnie.

  • Drives & Controls - VSD saves energy in hydraulic systems

    Hydraulic systems waste much of their energy as the fluid circulates at a constant  pressure, regardless of the amount of work carried out. Despite this, drives are not widely used in hydraulic installations, perhaps because the very impressive savings normally achievable in standard pump applications are not possible with the type of pump used in hydraulics. However, when Corus Colors on Deeside looked closely at the issue, the company found significant energy savings could be achieved

    When an ABB industrial drive was installed on a hydraulic pump, steel manufacturer Corus Colors on Deeside recorded a 70% energy saving.

    A trial was carried out by a graduate engineer at the company, Rob Chew, and Phil Tomkinson of Radway Control Systems. The aim of the study was to establish whether the drive would be a viable option for controlling energy consumption in hydraulic systems.
    The hydraulic system used during the trial is located on a production line used for retreating and inspecting strip material, driving actuators and web guiding systems in a 24-hour process.

    "As drives can be used to accurately control the speed of most motor driven machinery, hydraulic pumps should be no exception in this respect," says Chew. "Hydraulic systems waste much of the energy used, because fluid circulates continuously, although actuation is only required for very short periods of time."

    The energy used by the pump can be controlled by intelligently modulating the speed of the motor. The particular function used in this trial was the PID control, built into the ABB drive, which helps keep external values, like pressure, within certain limits. Pressure feedback is returned to the drive from a transducer. The drive automatically adjusts pump speed to maintain the system pressure.

    Pump design reduces saving potential
    Drives tend not to be used much on hydraulic systems, usually because the pressure is normally provided by a positive displacement pump, a type of pump that, theoretically, offers far less energy saving potential than the more common centrifugal pump.

    Unlike a centrifugal pump, which uses centrifugal force to throw fluid out through the discharge end of the pump, the positive displacement pump uses an internal mechanism that presses the fluid out. This means the output will be the same regardless of the resistance on the discharge side. The internal mechanism can be some type of gear or an arrangement with vanes. The installation at Corus Colors uses a positive displacement vane pump, driven by two 37 kW motors, one duty and one stand-by.

    Producing flow under pressure
    Positive displacement pumps are used in hydraulic systems because this type of pump can produce high pressure despite high system resistance. A centrifugal pump is far less effective working against a high system pressure. Its actual capacity can be anything from 0 to 100% of full capacity, depending on the resistance produced by the system pressure. Because the pressure in a hydraulic system is very high, a centrifugal pump would not be able to pump much at all against this resistance. A positive displacement pump, in contrast, only shows a very small change of flow when the pressure goes up or down.

    However, the energy consumption of the positive displacement pump is not reduced when the system resistance drops. For this reason, it does not offer the same energy saving potential as centrifugal pumps at reduced speed. While the centrifugal pump offers energy savings equal to the cube of the speed reduction, a change in flow by the positive displacement pump produces a linear change in power usage.

    But despite using a positive displacement pump, Corus Colors achieved significant energy savings by retrofitting the existing system with a drive. The pump speed was greatly reduced both when the system was in neutral and during actuation of the cylinders.

    Optimising speed
    Chew's trial aimed to establish whether system pressure could be maintained with reduced average motor speed, using a drive, with pressure data fed back to the PID control of the ABB drive from a pressure transducer. The installation was commissioned on a downshift as other maintenance was carried out on the production line.

    Vane pumps start losing their efficiency below 400 rpm, as the vanes are held in position by centrifugal force, so the pump efficiency had to be monitored throughout the trial as the optimum speed was sought. This was eventually established to be 450 rpm.

    Chew had concluded that leaving the drive just running in PID control would cause some unwanted side effects. The main issue was that a drop in pressure would be followed by an increase in motor speed in response to the pressure drop.

    The desired system pressure is 90 bar, while the maximum is 93 bar at full speed. As in many hydraulic systems, the on-load times are short. After actuation of the cylinders, the hydraulic system quickly settles back into neutral again. As the drive will have increased the motor speed rapidly to meet the drop in pressure, it is likely that it would overshoot the target of reaching a pressure of 90 bar, with the PID control having been set very high for a fast response.

    The system relief valve is activated at 93 bar so the system pressure will never get higher that this. As the drive only sees a small error in pressure of 3 bar, it may be slow to react. This means there will be a long transient time before the drive settles down to the required speed to maintain 90 bar in neutral and this will cause unnecessary waste of energy, sending excessive fluid back to the sump while the hydraulics are in neutral.

    Dual mode control
    The solution was to operate the drive in two modes, PID control and single-speed mode. The switching between the modes is controlled by the transistor output of the pressure transducer. When the hydraulic system is in neutral and the pressure is at the desired level, the drive runs at a single speed of 450 rpm, the optimum speed established through the trial.

    When the system is operated and the pressure drops, the transducer switches the drive into PID control. The desired pressure set in the PID is 93 bar, the maximum pressure for the system, and the proportional control is set very high to ensure a rapid response from the drive. Once the pressure increases to 90 bar, the transducer will switch the drive back to single speed mode. This will prevent any overshoot in speed and reduce energy waste.
    The drive's hysterisis control is used to stop rapid switching which could wear out components and pulse the motor excessively.

    Significant energy saving
    Once Chew had established the optimum speed, wired up the transducer and programmed the PID control, the installation was monitored for two days to compare the energy consumption between under drive control with direct-on-line operation. Energy consumption was measured before and after using an energy meter.

    When in neutral, power consumption was around 9 kW with direct-on-line operation. Under drive control, power consumption was reduced to 2 kW, a reduction of 77%. With the system under load, power consumption was reduced from 22 kW to 12 kW, a saving of 48%. As the on-load duty time for the system is 16%, the average energy saving over time was 70%.
    "The reduction in energy consumption under load initially surprised me, as it should take the same amount of energy to move a hydraulic cylinder a given distance regardless of whether a drive or direct-on-line operation is used," says Chew.

    Reduced peak power
    An experiment was set up to test the hydraulics on direct-on-line operation and under drive control with a single actuation on the largest cylinder. To record the readings, the drive's internal recorder was used with the DriveWindow software from ABB. This gave high sample rates over a short period of recording time. The drive was set up to run at a single speed of 1470 rpm to the mimic direct-on-line operation. The recording was then started and the cylinder actuated five times, once every five seconds. The procedure was then repeated with the drive in the dual mode setup with PID and single speed.

    The readings showed a similar performance between the two tests but a vast difference in energy consumption, the drive peaking at 20 kW while the system in direct-on-line mode peaked at 34 kW.

    "The test showed that the drive used a lower motor speed to achieve the required pressure," says Chew. "The flow rate will be lower, but the drive is still fully capable of matching the response times of a direct-on-line configuration."

    The reduced energy consumption will allow a payback time of just 18 months and reduce the company's carbon footprint by 33 tonnes of CO2 annually.

  • 20% discount on new IET Drives and Controls Handbook

    Commissioned by the Institution of Engineering and Technology (IET), the second edition of the Control Techniques Drives and Controls Handbook, edited by Professor Bill Drury, is to be launched on 6 July this year.  The handbook gives an insight into the technology and techniques of AC and DC motor control, from basic theory through to practical solutions.

    This book replaces the edition published in 2001 and according to Professor Drury, "Very little of the last edition has made it into the new one without at least some modification and there has also been a lot of entirely new subject material included."  This comprehensive and practical work runs over 750 pages and retails at £80. Electrical Review readers, however, can get 20% off when buying it through the IET by visiting www.driveshandbook.com.

    The handbook draws upon Control Techniques' engineering expertise in this field but encompasses all aspects of variable speed control applicable to all manufacturers' equipment, including AC/DC industrial motors, servo control, communications and system design.

    Recognising the handbook is used in a significant number of Universities as well as by industrial users, Professor Drury has added new sections covering basic electromagnetic and motor theory.  New developments in areas including power semiconductors, functional safety and control have also been included. 

    A detailed consideration is given to the ambient conditions which influence the specification of a drive and associated equipment through to the characteristic impacts of drives. Guidance on EMC, harmonics, thermal management, cabling and fusing have all been significantly updated, including changes to international regulations.

    The applications section has also been expanded, though given the breadth of this publication, it has been recognised that only core technologies and exemplars of use could be included.

    The structure of the Handbook has been radically redesigned into four parts to make it easier to access:
    -    Part A: drive types and core technology
    -    Part B: the drive in its environment
    -    Part C: practical applications
    -    Part D: appendices

    The index of the book has been revised to make it easier to find.

  • Energy University drives energy management awareness

    Schneider Electric has announced the launch of Energy University, a vendor-neutral, online educational community that provides the fundamentals needed to implement successful energy efficient solutions scaling various applications.

    The courses are designed to provide anyone involved in the decision-making, management, planning, design, or construction of a space impacted by energy, a level of expertise to address efficiency issues and apply safe, reliable and cost effective measures.

    "Schneider Electric believes there is a significant opportunity for sustainable energy savings that is unaddressed by industry and consumers today. Through Energy University, we expect to enable anyone to better understand and act on these opportunities, so they can do more with less," said Paul Hamilton, senior vice president, Energy and Solution University, Schneider Electric. "Energy University will reduce complexity and raise awareness by providing global users easy access to practical education on all aspects of energy management."

    Energy University courses are product-agnostic and focus on the critical concepts and best practices necessary to achieve a high degree of energy management.  Subject matter experts from all areas of the company assist in the development and creation of the courses. As the demand for new technologies and knowledge increases, Energy University will be incorporating additional courses to the programme.

    Currently, 11 foundational courses are offered- topics include:

    • Energy efficiency fundamentals

    • The economics of energy efficiency

    • Going green with leadership in energy and environmental design (LEED)

    • Trusted advisor program overview

    • Alternative power generation technologies

    • Data centre efficiency: Reducing electrical power consumption

    • Lighting basics for energy efficient applications


      Each course can typically be completed in less than one hour and an online platform makes learning convenient and accessible from any internet-ready computer. The self-paced learning experience is enhanced by an accompanying quiz for success measurement and preparation for the certification exam.  The certification verifies that a user has a comprehensive understanding of energy management and is able to independently handle situations related to energy awareness, problem solving and solutions design.

      Energy University is available on-demand via www.myenergyuniversity.com

     

  • Dedicated drives team for Schneider Electric

    Schneider Electric has announced the creation of a dedicated drives team within its industry business, headed up by the recently appointed national drives sales manager, Tony Pickering (pictured).

    Pickering joined Schneider Electric from Danfoss where he created a robust sales network across the European countries he was responsible for.

    Pickering explained: "The Schneider Electric business has always had a drives team within its organisation but this is currently being further strengthened via a tactical restructuring. The new organisation will support the company's regional sales activities and in addition will be split into industrial and HVAC dedicated teams.

    "We have decided to take this route as we have always had strong products in this arena and we want to make the team more visible in the marketplace, to showcase our world leading drive technologies" he continued.

  • Drives and controls - Don't waste the hard lessons of this recession

    The electrical industry could be at the forefront of helping organisations recover from the economic downturn, by installing energy saving equipment and green technologies that will also help with carbon reduction requirements. So says Jeff Whiting of Mitsubishi Electric

    Global greenhouse gas emissions are down 3% on last year, according to the International Energy Agency. Unfortunately this is not a massive triumph of green technologies, but is a reflection of the reduced economic activity brought about by the worldwide recession. This has given us a bit of a breathing space in which to reassess our position in regards to global warming. And we must be careful not to waste this advantage with a headlong rush to rebuild things as they were.

    Instead we need to take time to work out how we can do things better this time around. We won't get everything right, but the world needs to change and electrical engineers can play a vitally important part in building a better tomorrow.

    In a recession there is simply less work available, so businesses have to make financial savings. Ten or twenty years ago this tended to mean job cuts; but modern businesses run pretty lean and recognise that losing people also means losing skills that may never be replaced. So savings need to be found elsewhere.

    A big cost for most businesses is energy bills - and these can be controlled!

    Here we have a conjunction of an economic need to cut power bills and a social drive to become more energy efficient. Good housekeeping - switch things off, turning things down, checking the insulation - will pay worthwhile dividends. But the real benefits come with a long term commitment to control energy usage (and therefore costs) on an on-going basis.
    Probably the technology with the best energy saving potential is variable speed inverter drives, which are fitted to electric motors to control speed, and therefore costs. Electrical engineers have long known the basic rule that the energy saving is proportional to the cube of the speed reduction, which means that a small reduction in speed will give a huge reduction in running costs and energy used. Traditionally, financial managers have often only looked at initial capital outlay, not recognising the short payback and significant savings that can be achieved with such systems.

    A climate of change
    However with climate change now so high on the agenda, traditional thinking is being turned on its head. Governments around the world are introducing laws and guidelines to promote the adoption of inverters. 

    One clear example of this in the UK is the new Part L of the Building Regulations, which recommends inverters should be fitted to all pump and fan motors over a moderate 1.1kW. Doing this will improve the efficiency grade of the building and actually improve the value of the building asset. 

    A modern medium sized office building, for instance will have literally hundreds of motors tucked away behind access panels. Every fan has its own motor; pumps in the air conditioning, heating and water supplies are often motor driven: high powered extracts in the kitchens - motors are everywhere.

    Let's look at a typical example. A 100kW motor is not a cheap thing to buy. There are more costs in installing and commissioning it. Then there is regular maintenance. And, not least, it will be running up the energy bill every time it is used. And the last cost is by far the largest one!

    Such a motor will have a typical working life of 15 years. And it is of such a size it is likely to be assigned a duty where it is running 24/7. In this case its total energy consumption would work out at £75,000 per year.

    Interestingly, most systems have some sort of mechanical damping device to control or limit flow as motor systems are generally sized for ‘worse case plus' conditions they are never required to operate at. Include an inverter and you can control the speed thereby reducing the flow, but with the added benefit of significantly reducing the power requirements. Usually you would expect to find the motor never needs to run at more that 80-90% top speed. Often you can run it at a far lower speed, say 25-50%, and you could turn it right down or right off at weekends, bank holidays and possibly other times too.

    Do this and energy consumption would reduce significantly, possibly 50-70% - that is to say a saving of maybe £50,000 each and every year of its operational life. An inverter can be programmed to make all these speed changes automatically.

    But what of the initial capital outlay? Well most retrofit inverter installations will pay for themselves in 12-18months, fast enough to impress even the grumpiest of accountants. Further, there are now grants available and financial plans that mean you pay for the inverter as you achieve your energy savings. 

    Inverter installation costs are, naturally, far less if they are designed into new build projects, and the payback time is therefore reduced significantly.

    While there are many motors in an office, there are significantly more in a factory with lots of production plant or in a hospital with all its high tech medial apparatus, or in a leisure facility housing exercise equipment, catering, computer games etc.

    In fact, the manufacturing and production industries are by far the biggest users of energy, consuming about 40% of the total generation capacity. 70% of this figure (i.e. 30% of the total) is used to run electric motors, of which only 17% are fitted with energy saving inverters.

    And while you may think that 17% is a poor, it is streets ahead of the figure for inverter take up by other sectors of the economy.

    Culprits unmasked
    Until global warming was recognised as the crisis it so nearly is, for some reason government guidelines always fought shy of drives, not recommending them with the enthusiasm that might have been expected. But now the tide has turned.

    In a recent revison of the McKinsey report, the management consultants re-aligned the inclusion of inverters as being one of the most cost effective measures, creating a big impact on CO2 levels and global warming.

    The government is advised by McKinsey & Company, the international management consultants, who for some reason did not acknowledge the full carbon and money saving potential of drives until their most recent publication.

    Their initial report: Pathways to a low carbon economy: Version of the global greenhouse gas cost abatement curve, includes the McKinsey greenhouse gas abatement cost curve.

    A cost curve is a typical tool of management consultants - and let it be said - they are often very useful, condensing complex and multi-dimensional information into a simple two-axis graph. The problem with cost curves is users know how difficult they are to compile and that management consultants charge a lot for them, so they are pre-disposed to trust them and therefore use them blindly without questioning their accuracy.

    Unfortunately Version 1 of the McKinsey curve presented variable speed inverter drives as an energy saving solution with significant cost! A new Version 2 curve, now in circulation puts drives right at the top of the energy saving ranking, recognizing the high level of savings that are achieved with such systems. The savings are only bettered only by a wholesale switch to LED lighting and thermal insulation of commercial buildings. Drives are seen as greener than other industrial efficiency improvements, electricity from landfill gas, biofuels, geothermal and next generation hydroelectricity schemes.

    Let's look at some details of the report. The analysis finds that if no attempt to curb emission is made, they will grow by about 40% by 2030. There is potential, if everyone pulls together, to turn this around to a 35% reduction. This would cost about £200bn annually, or 1% of global GDP, and would hold global warming to just under 2°C, a critical figure if icecap melting and desert growth are to be contained.

    The International Energy Agency's report suggests the recent recession has bought us a couple of years on these figures. Unhappily, I would predict at least two more recessions before 2030, which might win us another six years (thereby giving us time for yet another recession and three more years).

    The report goes on to define four categories of abatement opportunities: energy efficiency, low carbon energy supply, terrestrial carbon (agriculture, forestry), and behavioural change. Of these energy efficiency has the most promise; it could account for about a third of all potential savings, uses mainly proven technologies and does not rely on changing human behavior.

    McKinsey looked at carbon reduction on a global scale, but this is not a scale familiar to most working engineers. They look at a rather smaller world; refurbishing some building controls, a single production plant or design of a machine.

    Until recently it was unheard of that customers or bosses asked for a reduced carbon footprint. But they are now being forced to do so (although it is often presented as a financial saving).

    Electrical engineers will be the ones who lead the widespread adoption of inverters and other green technologies. And now with business minds so focused on cost control is a good time to get a firm foothold in what will become a staple of the sector.

  • Drives save £77,000 a year on energy bills

    Drives from ABB are said to have helped one of the UK's largest holiday park operators save £77,000 a year on its energy bills for its swimming pools.

    Bourne Leisure, which owns brands such as Haven, Butlins and Warner Leisure hotels, has swimming pools at a number of its properties.

    James Chalmers, an ABB drives engineer, says: "Bourne Leisure had seen how successful ABB drives has been at the Hendra Holiday Park swimming pool and wanted to know if we could help them save money both on their pool pumping and AHUs."

    ABB Drives Alliance partner APDS was asked to investigate the energy saving potential for the swimming pools and a trial was conducted on two of the three filtration pumps at Bourne Leisure's Devon Cliffs site. The pump was monitored for a period before a variable speed drive (VSD) was installed. Monitoring with a temporary VSD fitted demonstrated that considerable energy savings could be made. The direct-on-line pumps were working at 50Hz drawing an average of 30 A. When the drive was introduced, this figure was reduced to 23 A during the day and 15 A at night, with no effect on water quality.

    APDS and ABB recommended fitting VSDs to the pumps feeding the pool filters. The pump filters operate by trapping dirt and debris in the sand filter and returning clean water back to the swimming pool. Pumping the water at a reduced flow rate improves the filtration process and removes more contaminants. The traditional method achieved this by increasing the diameter of the feed pipes and introducing a control valve to limit the flow. This was obviously wasteful as the pump was still running at maximum speed.

    Doug Pitt of APDS says: "The trial showed the predicted savings for each 18.5kW pump at Devon Cliffs was £4,899 per annum, giving a payback period of under six months. The actual savings exceeded those predicted in the energy report as the motor speed could be accurately mapped to pool utilisation."

    Craig Valentine, health and safety Manager for Bourne Leisure, said: "We had been looking at various techniques for saving energy, but the drives method was the most sensible way."

    ABB drives ranging from 3.3 to 30kW were eventually installed in 36 Bourne Leisure owned pools around the country, including two Butlins parks, making savings up to £11,000 depending on size of pool and number of drives. In total, the company is saving nearly £77,000 per annum on running its pools, with a total payback time for the entire project of just over a year.

    Said Valentine: "The conversion only takes a day, with most of the rewiring done at night, so there has been very little disruption for our guests. Overall, the project has gone very well."

    Other beneficial features of the ABB drives include the real time clock that allows the pumps to be started and stopped according to a schedule of use. The drives also have a boost button that can immediately take the pumps up to full speed for the backwash cycle. Reduced bearing wear of the pumps has also been another benefit of the drives, due to extended ramp times.

    ABB is working with a specialist pool company on phase two of the project which will see the drives receiving signals from a dosing machine. This will ensure the drives run at a speed more accurately matched to how the pool is used to ensure the correct dosing of additives such as bromine to maintain the optimum conditions in the pool.

     

     

  • Expanded intelligent DC drives range

    Control Techniques' new intelligent DC drive, Mentor MP, was publicly unveiled at the Nuremberg SPS/IPC exhibition in 2008, and the launch was a great success with units in the 25A to 210A range now in service around the world. At Nuremberg 2009 Control Techniques will showcase its new large size 2 models for the first time.

    The first shipments of the new Size 2 drive will commence before the end of the year, new models cover the range 350A to 1,850A and up to 690V.  Multiple drives can be connected together to control armature currents of up to 7,400A in 6, 12 and 24 pulse configurations. Every drive in this range ships with an inbuilt 20A field controller which is suitable for the vast majority of DC motors, however, for higher field currents and for upgrading older equipment a new standalone controller called the FXMP25 will be available. 

    A core strength of the Mentor MP range is its compatibility with Control Techniques' universal SM option module range, giving Mentor MP access to the latest onboard PLC and Motion engines, high speed Ethernet and Fieldbus communications and connectivity with modern high resolution feedback devices.

    Typical applications that can immediately benefit from Mentor MP include:

    * Metals
    * Printing
    * Material Handling
    * Rubber and plastics
    * Pulp and paper
    * Crane and hoist
    * Mining
    * Elevator and escalator
    * Active input for DC bus connected AC drive systems


    Control Techniques
    http://www.controltechniques.com/  

  • Router connects HVAC drives to IP network

    Drives can be easily connected to a HVAC system with BACnet, using an IP router from ABB. The RBIP-01 router eliminates the need for gateways and is compatible with all ABB HVAC drives, including older product generations.

    The RBIP-01 router transfers data between the IP network and MS/TP (RS-485), a network standard used by many devices in HVAC installations, such as drives. Unlike a gateway, the router does not interpret data or translate from one language into another, but simply passes on the data from one medium to another. This makes the router much easier to set up than a gateway and ensures that no information is lost during the transfer.

    ABB Limited

    01925 741 111

    www.abb.co.uk/energy

  • Drives show energy savings

    Users of ABB industrial drives and ABB standard drives can now see exactly how much  energy they are saving with a new application that displays the information on the drive's screen.

    The drives' built-in energy efficiency parameters work out energy savings of the application in kWh and MWh; the cost of the energy saved in a local currency; and the carbon dioxide (CO2) emissions equivalent of the energy saved.

    All these energy related measurements are displayed through the control panel's alphanumeric display and can be accessed by pressing a combination of the soft keys.


    ABB

    Tel: 01925 741 111
    Fax: 01925 741 212
    Email; This email address is being protected from spambots. You need JavaScript enabled to view it.
    Web: www.abb.co.uk/energy

  • Energy efficiency - Government pushes variable speed drives as top way to cut CO2

    Steve Ruddell, UK energy spokesperson for ABB, explains the incentives available to  industry to invest in variable speed drives, in an effort by the Government to curb CO2 emissions

    In recent years there has been an influx of regulations applied to the manufacturing industry that have a major impact on energy use. In 2001 the Climate Change Levy was introduced, followed by Climate Change Agreements. Then in 2005, the EU ETS came along followed in 2008 by the Environmental Permitting Regime. And more recently, the government launched its Carbon Reduction Commitment or CRC Energy Efficiency Scheme which is due to begin widespread implementation in April 2010.

    The CRC Energy Efficiency Scheme was announced in the Energy White Paper 2007. It will apply mandatory emissions trading to cut carbon emissions from large non-energy intensive users in the private and public sectors. A recent report from the Environment Agency indicates the scheme has the potential to reduce CO2 emissions up to 11.6 million tonnes per year by 2020 - the equivalent of taking four million cars off the road.

    CRC is designed to drive energy efficiency and carbon saving by giving organisations a financial incentive to do so through emissions trading, and combining this with Corporate Social Responsibility incentives through publishing organisations' performance in a league table.

    The scheme targets organisation's annual half hourly metered (HHM) electricity use, if that's at least 6,000 Megawatt hours (MWh) they'll qualify for the scheme - or typically those that spend £500,000 a year on electricity.

    All large energy users, from government departments to big-business, have to take part in the scheme from 1 April 2010.

    Organisations only need to report emissions in the first year (2010/11), then in following years they will have to buy allowances matching their emissions from energy use and then surrender them by the end of the year. In the second year (2011/12) extra weighting will be given to organisations 'taking action early' to improve energy efficiency.

    Organisations which use 'on-site' renewable energy like wind turbines or solar panels, by publishing the increased carbon savings from such measures, will get increased 'recognition' under the CRC.

    Methods to reduce energy consumption
    To reach the CRC levels there are several energy saving initiatives that can be introduced such as insulating buildings to a high standard, fitting low energy lighting, controlling building temperature to an agreed standard and fitting voltage optimisation technology. Other more detailed measures include compressor upgrades, compressed air leak survey, compressed air zoning, warm-up cycle timers, rapid roller-doors, computer linked roller-doors and smart metering. But undoubtedly the biggest impact on energy saving can come from applying variable speed drives to many of the electric motors used throughout industry and commerce.

    In manufacturing, nearly 60% of immediate energy savings can be achieved by looking at more efficient motor/drive systems, according to the manufacturers' organisation, EEF. It is still a little known fact 65% of all energy used in industry is consumed by the electric motor. And yet only about 5% of this installed based has a variable speed drive to control the motor speed depending on the demand. With some 10 million motors installed throughout the UK alone, the potential savings are huge.

    Record, report and reduce
    Presently, many organisations are busy measuring and recording their actual energy consumption and carbon dioxide emission usage. This is an excellent start, especially if you are one of the heavy-users caught by the CRC Energy Efficiency Scheme - this is simply a prerequisite. But it must be realised this is only the start.

    Ultimately, the only way to look good in the government's league table will be to cut consumption. For this, all of the aforementioned methods can be introduced especially the use of variable speed drives.

    ABB offers industry a free half-day energy appraisal, during which a qualified engineer will take a look at the most energy intensive applications and indicate the energy savings that can be made. The results can be staggering. Of course, an energy appraisal is only one element that companies need to consider. As a guide the EEF recommends the following:

    Know where you stand
    Understand what's being used and what's being wasted across your business - and what it's costing you.

    Prioritise action
    Prioritise the actions you'll take based on the payback each will deliver.

    Make plans
    Underpin your resource efficiency programme with clear objectives and targets.

    Monitor and review
    An environmental or energy management system will help you stay focused and make sure standards of performance are attained and then maintained. Certification to ISO 14001 or BS16001 demonstrates commitment for continuous improvement by the organisation.

    The Big Business Refit
    For those organisations with an energy bill less than £500,000 per annum, The Carbon Trust has launched The Big Business Refit, in which it is encouraging industry, through interest-free loans from £3,000 to £500,000, to invest in new technology like variable speed drives and energy efficient electric motors.

    In addition, the Carbon Trust is now investing an extra £15m in funding to help manufacturers become more energy efficient, with a new scheme, called the Industrial Energy Efficiency Accelerator. It is designed to spark a ‘low carbon industrial revolution' by helping manufacturers find new energy efficient processes by which to create their products with.

    Industrial Energy Efficiency Accelerator
    Diverse manufacturers such as Britvic, Highland Spring, Tarmac and Tesco have joined trade bodies such as the Food and Drink Federation and Dairy UK in backing the new programme.
    The programme is expected to reduce energy costs for manufacturers by more than half a billion pounds and to cut carbon emissions by more than three million tonnes. It will also increase the capacity of these manufacturers to respond effectively to the CRC Energy Efficiency Scheme.

    Through the Industrial Energy Efficiency Accelerator, the Carbon Trust aims to transform the traditional sector-specific processes that underpin British manufacturing. In partnership with industry leaders, the organisation will identify and demonstrate new, lower-carbon solutions that can be replicated widely across each sector.

    Dr Mark Williamson, Carbon Trust director of innovations, said: "More than a quarter of the UK's carbon emissions come from industry and we've got to find new opportunities to reduce them. The way to make truly substantial cuts is to get to the very heart of manufacturing. By rethinking the way manufacturers operate from the ground up we plan to spearhead a low carbon industrial revolution that will not only reduce emissions but will also increase demand for innovation, generate jobs and cut costs."

    Clearly, there has never been a better time to take a closer look at what the motors in your plant are doing for you.

  • Variable speed drives for fume extraction

    ABB has won a £1.6m order from Outokumpu for variable AC drives for the fume extraction system at its Sheffield plant.

    The project sees ABB supply four 1.2 MW fan drive systems to provide fume extraction for Outokumpu's stainless melting and continuous casting (SMACC) facility. Each package will consist of an ABB industrial drive, a transformer and an ABB high voltage motor. The systems will provide fume extraction for the melting shop generally and for individual units such as the electric arc furnace and the argon oxygen decarburiser.

    Replacing the existing direct-on-line motors, the variable speed drive fans will produce significant energy savings and achieve an annual saving in CO2 of over 5,000 tonnes. David Cobley, engineering manager for the SMACC facility, says: "This is a significant investment by Outokumpu and demonstrates the company's commitment to improving the energy efficient of its plant and its commitment to the environment by reducing CO2 emissions". This was also big factor in choosing ABB. The company is also a proven supplier of excellent equipment as well as a reliable installer."

    The contract includes the supply of four motor bedplates, removal of old equipment, a service contract, project management, integration of control equipment and an extended 36 month warranty. Installation is scheduled for late July and early August 2010.

  • Drives & controls - Energy efficiency – the holy grail

    Motor manufacturers have been challenged in today's low carbon environment to target one of  the holy grails of the motoring community, energy efficiency. Two significant approaches have found their way into mainstream motoring, automated stopping of the engine when idling at traffic lights, and conserving the energy generated in braking to optimise the fuel usage and reduce carbon emissions. In fact the second approach even found its way into Formula 1 as a way to get a performance boost. Jeff Whiting of Mitsubishi Electric looks at how inverter drive technology, in the form of the regenerative drive, answers real issues in industrial environments, and indeed demonstrates a number of other operational benefits

    Until a few years ago, when drivers stopped at traffic lights or a level crossing, they simply left their engines running. But now there are many campaigns to encourage switching off - in California it's already a legal requirement for commercial vehicles. But restarting an engine, even a warm one, requires an extra squirt of fuel, leading to extra CO2 and NOX, so regenerative technologies are being used to capture braking energy that was previously dissipated through hot brake discs and provide a carbon neutral kick start when the lights go green. A number of car manufacturers have automated this approach bringing clear energy reductions.

    Historically in industry, an electric motor was started and left running throughout the shift. There was often a good reason for this as starting motors usually took a huge energy inrush until it got moving and built up its own resistance. This power inrush could be up to 12 times the working current of the motor and therefore motors are usually rated with a number of direct starts allowed per hour. Leaving the motor running seemed quite a realistic approach. However, fitting a motor with an inverter offers a much softer starting regime, and is far less restricted in terms of available starts. This really opens up the opportunity to only run the motor during operational requirements, and to save significant energy by switching the motor on and off.

    A inverter drive offers even more energy ‘bang for its buck' by optimising energy used in the electric motor whatever the load, and also by running the process at lower speeds which can also save significant energy and therefore costs. The best savings can normally be made when running a fan or pump, as a slight reduction in speed can really impact the power consumption. Maybe this isn't a realistic goal of Formula 1, and wouldn't attract much of an audience, but it is well known that a smooth driver uses far less petrol than a boy racer. Uncharacteristically, Jeremy Clarkson and his Top Gear colleagues demonstrated this sometime ago by driving large cars from Paris to Liverpool on a single tank of petrol. By maintaining a steady, moderate speed, avoiding stop/start driving, rapid acceleration and hard braking, fuel consumption was kept in the optimum range and the total mileage proved to be way beyond what is normally achieved.

    The savings gained by using inverters in real terms are both financial, affecting a business' bottom line and ecological in the reduction of CO2 used. In fact it has been calculated that the CO2 savings made by the inverters sold in the UK each year relate to the CO2 used by 100,000 Business cars doing normal mileage.

    An inverter doesn't just save energy or allow a process to be optimised for changing loads and requirements. There are many types of industrial processes driven by motors. Some of these applications bring a number of other challenges which are easily addressed by today's high performance inverter drives. Typical of these is where energy in the process overhauls the power of the motor. To keep the process under control, this energy must be dealt with, and if possible used to power other parts of the production cycle. This was the principle of the Kinetic Energy Recovery System used for a short period of time in Formula 1 racing, but finding a far more appreciative audience in today's high efficiency and hybrid cars. Normally, under braking conditions, the weight of the car generates heat in the brake disks. With the latest technology, KERS uses this condition to capture the energy and release it during the driven part of the journey, thereby reducing fuel consumption.

    Consider an escalator at a deep London Underground station at rush hour. The ‘up' escalator will be working hard to lift maybe a hundred people over a considerable height. The ‘down' escalator will be carrying just as many people - and it will be creating energy as they descend. In power terms, the motor requires power to be fed into it to drive the loaded escalator upwards, whereas when descending, the motor has a load driving it, making the motor act as a generator. Under these conditions the power has to be controlled for the passengers need to descend in a safe manner. This is generally done by using an inverter to ensure safe control and a measured stopping function. Without this, an uncontrolled stop could have huge repercussion with people thrown every which way - mainly downwards into a big heap of limbs and bodies. People could be hurt and the legal repercussions last for years.

    To achieve this continuous control under all load situations, an inverter has to shed this extra energy somewhere. There are many mechanical ways to collect some of this energy - counterweights, winding sprints, etc - but most of them are fairly crude and only partially effective. As this generated energy is in the form of electricity, it is general to dissipate it in that form. In the past, vast banks of braking resistors were used to dissipate the electricity into heat. This could become a considerable fire risk anywhere, but doubly so in a dusty, hot underground machine room. However, a specially designed regenerative drive, such as Mitsubishi's Regenerative A701 drive, controls the load under all conditions and sheds the excess power by converting the kinetic energy into electricity and pumping it safely down the mains or even sharing it with other drives by connecting their power reservoirs together. The energy generated during the lowering stage can be dissipated and lost, or captured and reused. By contrast, a regenerative drive captures all of the energy and feeds it back into supply mains giving welcome savings in electricity bills.

    The basic requirements of a soft start-up and stop can be programmed into a regenerative drive quite easily. Throughout a normal day's operation of the escalator, the drive will still be minimising the energy used. As you can imagine, during rush hour the escalators are fully loaded with people rushing to get to and from work, yet for most of the day there will only be a trickle of people using them.

    A typical energy strategy would be to operate at full loading with optimum transfer speed to get the rush hour passengers through as quickly as possible, and then to slow the escalators slightly for the rest of the day where the speed requirements are not so prevalent. The use of a reduction in transfer speed will bring an immediate energy gain, which will be further enhanced by the inverter's innate capability to shed excess power when there are fewer people on the escalator. The next stage in the developing strategy takes its lead from the stop-start strategies beginning to appear in today's high efficiency vehicles. As previously stated, using an inverter means the motor can start and stop the escalator quickly and safely when required. Maximum savings will occur when there are no passenger requirements and the escalator can be stopped. Implementing controls which sense approaching passengers means the inverters can start the escalators and bring them up to speed before a passenger arrives to step onto it.

    Industrial electrical engineers have long known of the energy saving benefits of inverters, and although they might not be in a position to teach the likes of Button, Hamilton and Schumacher a thing or two about fast driving, regenerative drives show they know a lot about efficient recovery and use of kinetic energy in the real world.

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