Vacon NXS AC variable speed drives supplied and fitted by Digicon Solutions are delivering large energy ­savings at the Northampton plant of Levi Strauss

The drives were installed as part of a continuous improvement programme at the site that supports Levi Strauss’ commitment to ensuring that its operations always have the minimum possible impact on the environment.

Retrofitted to fan coil units that form part of the site’s air handling and chilled water systems, the new drives allow the running speeds of the fans to be reduced by up to 10 per cent, without in any way compromising the performance of the plant. At the present time, 12 Vacon NXS drives have been fitted on the site, with ratings from 5.5kW to 22kW, and there are plans to fit further drives of a similar size in the near future.

Prior to the installation of the drives, Digicon carried out a trial to verify the level of energy savings that would be achieved. This involved equipping one fan with a drive, and monitoring the before and after energy usage. The trial was carried out at no cost to Levi Strauss.

“Vacon NXS drives are ideal for this type of application,” says Karl Jones of Digicon, “especially in their IP54 versions. These are completely self-contained with integrated EMC filters and chokes, which means that they can simply be fixed to a convenient wall without the need to be fitted in an enclosure. That saves a lot of time and money. In addition, these drives are compact, reliable and quiet in operation and, of course, they offer excellent value for money.”

“The new drives are really proving their worth,” said Keith Jackson of Levi Strauss. “As is almost always the case, the fans were designed to have some capacity to spare when running at full speed. Now we can reduce their running speed so that their output accurately matches demand, and that is allowing us to cut our energy bills and to reduce our carbon footprint. The drives will pay for themselves in a relatively short period, and after that, they’ll just be saving us money.”

The Vacon AC variable speed drives for this project were supplied by Digicon within just two weeks of an order being placed. The installation and commissioning of each drive took less than a day and the work was carried out with minimal disturbance to Levi Strauss’ operations.


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