Danfoss Drives' VLT Low Harmonic Drive eliminates harmonic disturbances on the supply grid by actively imposing currents into the grid
Danfoss Drives introduces the VLT Low Harmonic Drive. VLT Low Harmonic Drives don’t reduce or mask current distortion; they perform real-time analysis and actively impose currents, as needed, to restore and ensure the highest possible quality sine waves from the power supply grid.
VLT Low Harmonic Drives share the same modular technology platform as Danfoss’ VLT high power drives to deliver functionality, quality and reliability, and offer 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.
VLT Low Harmonic Drives cause no increased winding 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. While the performance of other low harmonic technologies depends on the stability of the grid and load or affect the controlled motor, VLT Low Harmonic Drives continuously regulate the network and load conditions without affecting the connected motor. VLT Low Harmonic Drives are motor friendly, with output impulse and shaft voltages compatible with motors conforming to IEC 60034-17/25 and NEMA-MG1-1998 part 220.127.116.11.
The VLT Low Harmonic Drives' 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 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.