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Energy Saving


Energy Saving download_pdf_btn

Variable speed drive systems supplied by drive technology expert, Ralspeed, have enabled Whitford Plastics, a leading supplier of fluoropolymer coatings, to reduce the carbon footprint of the extract fan installation at its manufacturing plant in Runcorn by more than 65%. Additional benefits of the new drive systems include lower running costs, extended equipment life, and reduced noise levels.

To ensure that its production operatives always have a clean and pleasant environment in which to work, Whitford Plastics makes extensive use of air extraction systems. Until recently, the fans used in these systems were driven by motors with ordinary direct-on-line starters that provided no speed control.

However, in their constant quest to improve the energy efficiency of the company’s operations and to minimise environmental impact, the engineers at Whitford Plastics decided to take advantage of Ralspeed’s energy appraisal service, which examines drive applications and provides information about the energy savings that can be achieved by using the latest drive technology.

In the case of Whitford Plastics, the information produced by the appraisal service was compelling. Each of the extract plant’s 7.5 kW fan motors was running at full speed for 59 hours per week, 50 weeks of the year, consuming 18,800 kWh of electricity per year at a cost of £1,540.

On the basis of its investigations, Ralspeed suggested fitting the fans with variable speed drives that would allow them to run at a speed optimally matched to the requirements of the manufacturing process. Calculations showed that this would allow the annual consumption for each motor to be cut to around 6,500 kWh and the energy cost to £528. The calculations also showed that the carbon footprint of each fan would be reduced from 8.09 tonnes of CO2 per year to just 2.78 tonnes.

“After seeing these figures, we decided that we wanted to go ahead with installing variable speed drives, and that we should seek funding support from the Carbon Trust,” said Des Griffiths, Plant Engineer for Whitford Plastics. “Ralspeed was very supportive in helping us to prepare and make our submission to the Carbon Trust. As a result, we got a quick decision, and we secured an interest-free loan to cover the cost of the project.”

To date, Ralspeed has converted five extract fans to variable speed operation, and conversion of the site’s remaining fans is planned for the near future. In each case, the conversion has involved fitting a control panel designed and built by Ralspeed, which incorporates a Vacon NXL AC variable speed drive. These drives were chosen on the basis of their consistent performance, proven reliability and value for money.

Once the new drive systems had been installed, it quickly became apparent that they would not only reduce energy usage and costs, but that they would also provide other important benefits. For example, smooth controlled starting and stopping of the fans, as well as the lower running speed for much of the time, is minimising wear and tear on the drive belts and bearings, which will extend the life of the equipment and reduce maintenance requirements.

In addition, when they are operating at reduced speed, the fans run much more quietly, something that is greatly appreciated by the plant operatives who now find that they can converse without shouting!

“The installation of the new drive systems went very smoothly,” said Des Griffiths, “and there was minimal disruption to the operation of our plant. We received excellent advice and support from Ralspeed at every stage of the project, from the initial appraisal right through to installation and commissioning, and we’re delighted with the savings we’re making. This has, without doubt, been an exceptionally worthwhile project.”

Ralspeed will continue to provide support for the systems it has supplied to Whitford Plastics. As an official Level 3 Service Partner for Vacon, the company is fully equipped and trained to diagnose problems and, in the unlikely event that it should prove necessary, to provide warranty repairs for the drives.

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Pumping The Dock Dry


Pumping The Dock Dry download_pdf_btn

Faced with the requirement to pump 3m litres of water from Liverpool’s Langton Dock in just three hours, with potentially serious and costly consequences if things went wrong, Exsel Pumps decided to rely on variable speed drive systems from Ralspeed to control the pumps it would use for the challenging project.Currently, £10 million is being invested in upgrading lock gate facilities at the Port of Liverpool, one of the largest and busiest container ports in Europe. An important part of this project involves refurbishing the caissons used in Langton Lock. This Lock, one of the busiest in the port, is divided into three sections, with caissons between the first and second sections, and between the second and third sections.

It would be too costly and disruptive to take the lock out of service for the whole duration of the project, which will take around three years. The decision was therefore taken to refurbish the caissons one at a time, which would allow the lock to continue to function while the work was being carried out, albeit with reduced flexibility.

The first phase of the project was the removal of the 1,600 tonne outer caisson, which was then sailed to the top end of the dock and moored up. Once this was complete, the next phase involved removing the 4,000 ton refurbished middle caisson from the recess from where it had been refurbished and sailed down the lock to the outer recess, where it was then reinstalled and commissioned. The next stage was to sail the outer caisson into the refurbishment recess for repair and refurbishment.

To achieve this changeover of the caissons it was necessary to pump out and refill the caissons recess, which holds 3m litres of water, several times. And, in order to limit the amount of time for which the lock was out of service, and to cater for variations in the tides around the dock, the time available for each of the emptying and filling operations was to be completed in less than three hours.

Exsel Pumps has wide knowledge and experience of supplying pumping systems for such demanding applications, and offered four 200 kW pumps, two of which were configured for emptying the dock, the other two for filling it. The engineers at Exsel knew, however, that they would need dependable variable speed drives to control these pumps not only to ensure smooth flow of water, but also to minimise the peak load on the electrical supply when the pumps started. As the electricity supply was generator fed, the use of a variable speed drive enabled a reduction in generator size and a reduction in fuel consumption.

Since Exsel Pumps required the drives only for the duration of the project, it decided that it would be more cost effective to hire them rather than buy them. It therefore approached Ralspeed, a company that specialises in providing drive systems for hire, and that has the resources and expertise needed to configure systems such a demanding application.

For this project, Ralspeed supplied two custom-built drive systems, each comprising a 200 kW Vacon NX drive and ancillary components mounted in a rugged weatherproof enclosure. Since filling and emptying operations would never be carried out simultaneously, rather than providing four separate drives Ralspeed supplied a changeover switching system that would allow the drives to be switched almost instantly to work with either the filling or the emptying pumps. This arrangement provided a very cost effective solution.

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The Torq-master 2000 has been used on hundreds of pumping applications, on sizes ranging from 5.5kw to 550kw.

We recently supplied 25 stand alone soft start panels built to customer specification for Selwood Pumps Ltd as part of their hire fleet. These units had to be of robust construction on a 12” stand along with a Drip Shed. Also various plug and socket arrangements were used for easy customer connection.

Ralspeed also designed a soft start system for fire pump application, where at full speed, the electronics switch off completely, the by-pass contactor holds in and in the event of a fire the machine will ‘run to destruction’. One such system was supplied through Parmley Graham Ltd to Rosyth Dock Yard for their 250kw fire pump system.

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Ralspeed have successfully started many different types of compressors and chillers. Such applications have recently included:

  • 31 Carrier chillers at Canary Wharf, London, using Torq-master 2000 Soft Starters ranging from 450kw to 750kw. The total power being 17.4mw.
  • 3 York Screw Compressors installed in a fish freezing plant at Peterhead, using 3 × 560kw Torq-master 2000 Soft Starters.
  • A Grasso Screw Compressor which was installed in a Pea Freezing plant at Eyemouth, using a 450kw Torq-master 2000 Soft Start unit.
  • An Ingersol-Rand ‘Centac’ compressor recently commissioned at Allied Turbo’s Skelmersdale, using a 450kw Torq-master 2000 Soft Start unit.

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Rock Crushers

Ralspeed have completed many projects involving various different types of rock crushers. Impact Crushers, Jaw Crushers and Cone Crushers have been successfully started using the Torq-master soft start unit. Recently completed projects include:

  • 5 Impact Crushers for Powerscreen Canaries S.L. using 160kw and 200kw soft start units on generator fed applications in Tenerife, Lanzarote, and Fuerteventura. All of these soft starters were manufactured by Ralspeed into robust Enclosures and to customer specification.
  • 200kw Mobile Impact Crusher, which utilised a Ralspeed Frequency Converter to accelerate the motor to speed in less than full load current (approximately 190A) to minimise the size of the generator required on the mobile chassis.

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Ralspeed have successfully applied many soft start units on fan applications, here are just a few:

  • One such application involved supplying Dam-Head Creek Power Station with 3 of our 186kw soft starter panels, again built to customer specification with top entry required and short delivery time was achieved.
  • As well as the soft starters we have also built many frequency converter panels for Swift Air Movement Ltd who require a particular system involving 2 frequency converters in 1 enclosure along with a remote control system for supply and extract in kitchens.

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Off Shore

Ralspeed have successfully applied many soft start units on fan applications, here are just a few:

  • One such application involved supplying Dam-Head Creek Power Station with 3 of our 186kw soft starter panels, again built to customer specification with top entry required and short delivery time was achieved.
  • As well as the soft starters we have also built many frequency converter panels for Swift Air Movement Ltd who require a particular system involving 2 frequency converters in 1 enclosure along with a remote control system for supply and extract in kitchens.

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  • Torq-Master Soft Starter With Fitted Bypass Contactor 75-110kW
  • 3 Pole Contactor 11kW - 15kW
  • VersiStart Range
  • Variable Speed Drive Panel 185-200kW for Hire
  • IP54 Soft Starters 22Kw to 90Kw
  • Danfoss Vacon 100 GP 0.75kW-160kW
  • Danfoss Vacon 10 Compact 0.25kW-5.5kW
Page updated 4th Feb 2019, 09:02
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