The air-compressors were operating 24 hrs/day or 720 hrs/month with an equally loaded and unloaded duty cycle. This meant that a large part of the energy was wasted.
After the installation of two VLT® drives of 200 kW each, with load sharing the electricity cost for the unloaded time has been reduced by US$ 336 per month. With the VLT® drives, the energy consumption is adjusted to the load requirements and the energy bill was reduced from US$ 18,000 per month to only US$ 11,664 - or more than 30% savings.
The energy savings have been carried through with no sacrifice of productivity.
The second benefiot from VLT® control is improved lifetime of the compressor.
Beat Japanese competitor
Despite the fact, that the Japanese owners had specified drives from a Japanese provider, they were convinced to use an European product. Danfoss drives were introduced and recommended by a partner pointing out the differences in reliability and quality, and finally Nissan agreed.
The main reasons for the customer chosing Danfoss were the capability of the Danfoss partner in retrofitting air-compressors with guaranteed savings and the EMC and RFI compatibility of the VLT® drives.
