  |
|
| << back to Energy Home |
|
 SEH Europe Ltd KnaufAlcopor Ltd BMW
Group BPI
Films Community Playthings West of Scotland Water Creda Mayflower Vehicle SystemsAn ABB drive is helping a semiconductor company save energy whilst providing increased capacity on its water ring main pumping system. The installation of the drive has reduced the duty for the pump to 60 percent during normal conditions and gives the system increased capacity to deal with the higher demand for water of new machinery. There was also a significant energy saving, which will give a payback time of around 16 months. SEH Europe Ltd., a major manufacturer of semiconductor wafers, was experiencing problems with the pressure in its water ring main, which supplies the whole plant with its water needs. The ring main is approximately 200 m long with tap points along its length for supplying production machinery with water. To maintain pressure when water was being tapped off, the system employed a relief valve to ensure adequate supply at a pressure that was not too great for the pipe work. Problems occurred when a new machine was installed. Its water demand was so high that it caused a severe pressure drop in the system. The existing pump had the capacity but increasing the system pressure caused extreme turbulence in the delivery lines to machines, so-called water hammer, which was damaging the pipe work. SEH called in Proshield, a company specialising in water control solutions. They recommended a variable speed drive and contacted ABB Drives Alliance Partner EDC (Scotland) Ltd. Proshield's Business Development Director, Bob Jarvie, says: "We chose a Comp-AC drive from ABB because it is easy to program and has a control algorithm ideally suited to this application." Proshield installed the drive along with a pressure sensor. Using the control algorithms in the drive, a control system was set up which matches supply to demand according to the signals received from the pressure sensor. The pump control system now took the place of the pressure relief valve in maintaining system pressure under various demand conditions. The pressure relief valve was set higher to allow a small amount of flow under no demand conditions to ensure that the pump did not overheat. This also protected the system against high-pressure surges. "We like the ABB drives because we know ABB complies with the latest regulations on EMC" Jarvie concludes. Top of the page KnaufAlcopor Ltd in St Helens, Merseyside is saving £50,000 worth of energy per year, since replacing the existing variable speed drives on its insulation forming conveyor with new DTC drives from ABB. KnaufAlcopor Ltd turned to ABB, which provided the solution through ABB Drives Alliance member Central Electrical. Ken Tym of Central Electrical comments: "An upgrade was essential as the existing drives had come to the end of their life. We supplied three ABB ACS 607 drives and overhauled the existing motors to increase their lifespan. This resulted in improved reliability of the forming section, with less downtime, increased production and reduced energy consumption by 20%." The ACS 607 drives control the speed for the fans in the forming section. These provide suction underneath the forming conveyor as part of the overall insulation manufacturing process. The process starts with molten glass running through an electrically heated brushing, flowing into a fiberising machine spinner. The spinner rotates at 2,000 rpm and glass fibre strands are formed through holes on the outer wall. The fibres are then sucked on to a conveyor with suction provided by the forming fans. The final manufactured product is either slab or roll formed mineral fibre insulation product. Closed loop control is provided, by measuring the suction with a probe and pressure transmitter. Maintenance leader Ricky Hill of KnaufAlcopor Ltd explains why ABB equipment was specified: "We received a complete solution from Central Electrical including ABBs ACS 607 drives. The equipment has improved the process reliability with added benefits of 20% saved energy and running costs." Top of the page ABB drives installed on the new MINI paintshop at BMW Group Plant Oxford are saving the company £24,000 a year in electricity costs. Twelve ABB Comp-AC drives, ranging from 11 to 37 kW, have been installed by ABB Drives Alliance partner MKE Drive Systems to run pumps on the pre-treatment plant. "Following an energy audit, we recommended the Comp-AC range as being the most cost-effective option for the application," says MKE drive manager Gary Palmer. "We installed the drives and also implemented a communication network that would enable BMW to control the drives from remote PLCs." Some of the pumps on the line showed dramatic savings once they were being run by the variable speed drives. "One pump was drawing 27kW, once it was properly speed controlled by the ABB Comp-AC drive we found it needed to draw only 6 kW. We have also installed a drive on the air extraction fan on the line, reducing the demand from 75kW to only 32 kW." Variable speed drives achieve these energy savings by driving the motor at the speed needed by the process. This contrasts with the wasteful practice of running the motor at full speed and then choking off the output, air or water in the case of fans and pumps, with some kind of mechanical device, such as a baffle or valve. "The main benefits we get are the flexibility to increase and decrease speed at will, compared to the previous method based on adjusting the pump valves," says Steve Edmunds, maintenance shift manager at BMW Group Plant Oxford. "We have now found the optimum speed for the pumps and are saving about 480,000 kWhrs a year on this facility." "We have standardised on ABB motors throughout the plant, so it was natural to opt for ABB when looking for a variable speed drive for the pumps on the pre-treatment plant." Payback time was only six months for the system. Top of the page ABB drives have helped a manufacturer of plastic film cut its energy bill by 66 percent for its slitter-winder machine. BPI Films of Sevenoaks in Kent produces 13,000 tons of plastic film a year for customers in the food and medical packaging industries who laminate it to other substrates. The company has a slitter-rewinder, which it uses to rewind film produced by other machines. The machine was operated using old hydraulic gears, with ABB motors but without encoders and drives. The hydraulic gears proved inefficient and unreliable and were subject to breakdown and therefore needed much maintenance. Ron Jeffrey, Engineering Manager for the plant, says: "The hydraulic system suffered from oil leaks. We constantly needed to replace the oil and costs were rising." BPI decided to replace the hydraulics with an ABB variable speed drive. Says Prudence: "We have standardised on ABB motors and drives throughout the plant and so looked for an ABB drive to use on the slitter-rewinder." The application uses two 75kW ACS 600 drives - one as the main drive to regulate the speed of the machine by driving a rubber covered roller, while the other drives the winder core shaft. The main drive reduced the demand of the principal motor from 22A per phase to 7A per phase, a saving of 66 percent. Even with the winder core shaft motor being driven, used to give extra torque when winding sticky materials, the overall energy saving is 33 percent. Using ABB winder software, the main drive takes signals from the winding machine, processes them and outputs a speed or torque signal. This keeps the motor running correctly and maintains the correct tension in the material, taking account of the changing diameter of the reel. The drives were commissioned by Martin Davenport, Account Manager, of ABB. "The ACS 600 drives used on this application use ABB's Direct Torque Control (DTC), overcoming the limitations AC drives have in controlling torque", says Davenport. "Because DTC can work out the speed of the motor accurately, no encoders are needed, saving further expense. Usually a drive needs an encoder to improve its precision, particularly at low speed, ABB's DTC drives can achieve maximum torque at zero speed without an encoder." Top of the page A 30 kW Comp-AC drive from ABB is helping a wooden toy company reduce the noise in its workshops, as well as save over £700 a year in energy. Community Playthings is a company run by the Beechgrove Community, a religious community near Sandwich, in Kent. For the past five years, the company has produced wooden items such as workbenches, blocks and toys for sale to schools. Community Playthings approached ABB Drives Alliance member MKE Engineering Group in Sittingbourne as it was experiencing problems with the dust extraction equipment in the workshop. The workshop has an extractor fan for removing wood dust from the air through ducting, previously based on a 30kW motor driving a fan. It ran at a constant speed, regardless of the number of machines working or the amount of dust in the air. The manager of Community Playthings explains: "The system was too powerful for present use and created a lot of noise." MKE Drive Systems recommended the 30kW drive from ABB. Gary Palmer of MKE says: "Each woodworking machine in the workshop now has its own vent, connected to the air extraction ducting. When the machine is switched on, the operator opens the vent, causing the pressure in the ducting to drop - when the machine is switched off, the vent is closed and the pressure rises. "The drive uses a pressure differential sensor, ensuring that the correct air pressure and volume is maintained in the ducting, to avoid damaging the ducting and wood dust settling in the ducts." The noise in the workshop has now been substantially reduced, and with the energy savings, the system will pay for itself in 14 months. Top of the page The efficiency of West of Scotland Water's Lomond Street Wastewater Pumping Station in Helensburgh, West Dunbartonshire, has more than doubled since two ACS 600 AC drives from ABB were installed. The company predicts the drives - supplied and installed by ABB Drives Alliance partner EDC (Scotland) Ltd - will save at least £80,000 in electricity costs over a 20-year life span whilst minimising the risk of overflowing, as pump throughput has been increased from 14 to 30m3 per kWh consumed. "Indications are that the electricity consumption has been reduced by 48% compared to the same period in the previous year", says Charles McCaig, Electrical Design Engineer at West of Scotland Water's Planning & Capital Procurement Department. The station, pumping waste water to the Ardmore treatment works some 2½ km away, is of the traditional separate wet/dry well design. The wet well is monitored with ultrasonic level instrumentation, generating a speed reference signal, which increases or decreases the pump speed and allows the start and stop levels to be selected. This results in the motors running between 73% and 88% duty, which is the optimum speed range for energy efficient operation of the pumps. This arrangement replaces simple on/off control of the motors, with the level monitored with a mechanical float. Flow meters now monitor the performance of the pumps. Combined with the kilowatt-hour readings from the drives, this gives a pumping index for each pump. A decreasing index indicates wear in the pump, enabling West of Scotland Water to optimise the pumps' service intervals. The old pumps were estimated to have a pumping index of 14m3 per kWh. After fitting new pumps and drives, but still running at the same speed as the old pumps, this increased to 21m3 per kWh. With the drives interfaced to the analogue reference signal, this was further improved to 30m3 per kWh. "I estimate that 44% of the savings can be put down to maintenance and 56% to the drives," says McCaig. With the number of pumping cycles being increased, the holding capacity of the wet well and combined sewer are able to cope with a greater flow than the old system would allow, decreasing the risk of overflow. The installation has also reduced noise. The ACS 600 drives feature motor flux optimisation, making the pumps quieter when in operation, which is of importance in the residential area where the station is located. "Already small decreases in pump speed give large energy savings, when a variable speed drive is used," explains Allan Murray, Managing Director of EDC, Ayrshire, the company that supplied, programmed and commissioned the system. "This is because decreasing a centrifugal load, such as a pump, gives a power decrease based on the cube of the load. "We also supplied energy efficient motors to the system to further improve energy efficiency, as the gap between standard and high efficiency motors becomes even greater in variable speed operation. "The use of the reference signal from the level transmitter also shows what can be achieved when using drives in conjunction with level monitoring equipment. "If this type of system can be used for the majority of wastewater pumping stations then this can ultimately be of great benefit to West of Scotland Water's customers as well as the local environment." Top of the page General Domestic Appliances Ltd, at its manufacturing plant in Stoke on Trent in Staffordshire, manufactures 12,000 cooking products a week for its market leading Creda, Hotpoint and Cannon brands. As part of a continuous programme to improve quality and energy efficiency at the factory, the company decided to look at the energy consumption of its wet fume extraction plant, which extracts waste vitreous enamel from four paint booths. Some of the booths were not in constant use and were closed off by a mechanical shutter, yet the 132kW fan used to extract the waste enamel was run at a constant speed, wasting energy and money. Plant engineer Andy Rowe, asked Glen Hickman of ABB Drives Alliance partner Central Electrical, to carry out an energy appraisal on the plant, with a view to cutting energy consumption. Central Electrical's calculations showed that the speed of the fan could be reduced by 20 percent, resulting in a 56 percent reduction in power from 118kW to 51kW, saving over 440,000 kWhrs a year. Central Electrical recommended an ABB ACS 600 AC drive, supplying and commissioning the equipment. The appraisal was repeated after the drive was commissioned to confirm the estimated savings figures. Andy Rowe says: "Central Electrical estimated we would save approximately £16,000 on the energy bill for the wet extraction plant in the first year. In fact we saved £17,000 and achieved a payback period of only four months." This type of energy appraisal is the cornerstone of ABB's new six-step energy plan, designed to help companies save energy in preparation for the introduction of the Climate Change Levy. ABB Drives Alliance members collect and analyse data from the customer's site using dedicated software and prepare an Executive Summary and a detailed Engineer's Report. They also help implement the recommendations and train staff at the client company to continue the process. The appraisal process can involve effective motor management schemes to maximise savings, as well as replacing older, less efficient drives with new, more advanced drive technology such ABB's DTC. Says Glen Hickman: "The energy consumption over a typical week was assessed with an energy monitor. Then, using a software package that analyses fan operations and energy use, we were able to calculate a speed reduction that would save energy while still maintaining the required sufficient extraction from the plant." Top of the page Over 80% saving in the running cost of paint plant motors is being achieved by a Coventry-based vehicle body panel manufacturer following the installation of ABB AC drives. "We were cynical at first about the huge savings that were being claimed," says Pat O'Sullivan, Facilities Manager for Mayflower Vehicle Systems, which manufacturers body panels for, among others, Aston Martin and MGF cars. "We believed that anyone suggesting up to 80% saving had probably loaded the product price to cover it. " But a SEAchange energy audit of the paint plant by ABB Drives Alliance Partner, Sentridge Control, revealed that the 30kW phosphate/ alkali rinse pumps - used in the nine stage pre-treatment system - needed the motors for just over two minutes of its eight minute duty cycle. In addition, the motors were running for 10 hours per day. Unlike AC drives, the existing star-delta starter arrangement meant that the motors could not be turned on and off quickly to meet the rinse pumps duty cycle, without severely damaging the motors windings and bearings. "Due to the ABB ACS 600 and Comp-AC drives, we have now been able to change our control strategy such that today we have cut the running costs of these pumps by 87.9% - even greater than the original 84%," says O'Sullivan. "The additional benefit is that the cost savings are immediate." Such were the projected savings that the management of Mayflower committed £30,000, which had not been budgeted. The money was used for the purchase and installation of six drives for the phosphate and alkali rinse, chemical and soap pumps and a further 11 drives for other pumps and cooling tower applications ranging from 2.2 kW to 55 kW. The investment is expected to yield a return in less than 12 months. This will be seen in a direct reduction in Mayflower's energy bill. O'Sullivan explains: "Sentridge had one compelling phrase: "Do you want to save £98,000 off your electricity bill? Can you afford not to?" Other savings have resulted from reduced maintenance. For example, the 11 kW soap pump was throttled manually to achieve 3 bar, but the valve would regularly work loose. Using PID control on the AC drive, that now controls the pump, not only avoids the manual valve adjustment, but, provides a faster more reliable control method. Mayflower's motivation for the energy audit had been two-fold. Firstly there was the Climate Change Levy (CCL), a government energy tax that came into force on April 1st this year. Secondly, Mayflower has implemented the environmental management system standard, ISO 14001 and as such is driven towards meeting its environmental targets, which includes a significant reduction in CO2 emissions. But such are the savings achieved using the ACS 600 and Comp-AC drives, that according to O'Sullivan, any additional saving that can be made from the CCL such as through Enhanced Capital Allowances, is a bonus. "Until Sentridge visited us, we had found the information available on Climate Change confusing and unclear. We were struggling to understand just how it applied to us. We wanted to save money and quickly" Sentridge Control's SEAchange energy audit is a systematic examination of key pump and fan applications that include the monitoring of energy consumed both before and after the change to AC drives. So confident were Sentridge about the results that the audit would achieve, the company loaned an ABB drive to Mayflower to test its findings. Top of the page |
|