VLT® Low Harmonic Drive from Danfoss Drives Named 2010 Design News Golden Mousetrap Finalist

VLT Low Harmonic Drives share the same highly modular technology platform as Danfoss’ popular VLT high power drives, to deliver time-tested and field-proven functionality, quality and reliability. Additionally, the VLT Low Harmonic Drive shares many of the same features such as high energy efficiency, backchannel cooling and user-friendly operation. These drives are available in the power range 132 – 630 kW high overload, 160 - 710 kW normal overload, and voltage range of 380 – 480 VAC, 50 – 60 Hz. They meet the IEEE519 recommendation, are available in an IP 21/NEMA1 or IP 54 (hybrid) enclosure, are UL, cUL and Ctick listed, and carry the CE mark. They are well suited for:
• Meeting the toughest of harmonics recommendations/standards
• Installations that are generator-powered, or that have generator back-up power
• Soft power grids
• Grids with limited excess power capacity

“In essence, the filter portion of VLT Low Harmonic Drives has the same working principle as a set of noise cancelling headphones, where the noise or distortion is measured and a computer phase signal is imposed to compensate for that noise. As a matter of scale, noise cancelling headphones can inject 100 mW at 50 - 1000 Hz, where VLT Low Harmonic Drives can inject several hundred watts at 250 – 2000 Hz,” says Gregers Geilager, Product Manager of Low Harmonic Drives.

VLT® Low Harmonic Drives cause no increased motor stress and have no impact on bearing life. They provide the user with a full readout of the unit performance towards the grid, including a graphical overview of grid behavior. Where the performance of other low harmonic technologies depend on the stability of the grid and load or effect the controlled motor, VLT Low Harmonic Drives continuously regulate the network and load conditions without affecting the connected motor. In fact, VLT Low Harmonic Drives are motor friendly, with output impulse and shaft voltages compatible with motors conforming to IEC 60034-17/25 & NEMA-MG1-1998 part 31.4.4.2, as per standard VLT® Drives.

A unique design uses a ducted back channel to pass cooling air over heat sinks with minimal air passing through the electronics area. This allows 85% of the heat losses to be exhausted directly outside of the enclosure, improving reliability and prolonging life by dramatically reducing temperature rise and contamination of the electronic components. There is an IP 54 seal between the back-channel cooling duct and the electronics area of the low harmonic drive.

With the increased use of electric loads, or more directly, non-linear loads in power systems and electrical distribution equipment, the issue of preventing or suppressing harmonic disturbances is growing significantly. After many years of growth in the drives sector, only one out of eight motors is operated by a frequency converter. Because of the innate problems that multiple electronic loads bring into a facility, there is a growing concern to provide a clean, stable power network. The application of Low Harmonic Drives is one solution that presents a wide variety of standardized configurations, appropriate for a vast array of industrial applications.

About Design News
Design News congratulates the winners and finalists of the 2010 Golden Mousetrap Awards for the great work they've done to develop new and innovative products for design engineers. These products, as always, showcase the highly imaginative ways that today's engineers are 'building a better mousetrap,' and we thank them for their contributions, says Jennifer Roy, Managing Editor, Design News.

For more than two decades, the Design News Awards Program has recognized engineering innovation and creativity in product design. For 2010, Golden Mousetrap awards were given in four major categories: Electronics, Motion Control/Automation, Hardware/Software, Materials/Fastening/Joining/Assembly, and 20 subcategories. Design News editors gathered a record number of entries and, based on their expertise in each technology area, painstakingly selected our winners and finalists.