harmful airborne liquids are water, oil, or corrosion onmetal parts.Excessive dust particle levels are often found on instal-lation enclosures and existing electrical installations. Oneindicator of aggressive airborne gases is blackening ofcopper rails and cable ends on existing installations.D and E enclosures have a stainless steel back-channeloption to provide more protection in aggressiveenvironments. Proper ventilation is still required for theinternal components of the drive. Contact Danfoss formore information.2.5 Vibration and ShockThe frequency converter has been tested according to theprocedure based on the following standards:The frequency converter complies with requirements forunits mounted on the walls and floors of productionpremises, as well as in panels bolted to walls or floors.• IEC/EN 60068-2-6: Vibration (sinusoidal) - 1970• IEC/EN 60068-2-64: Vibration, broad-band random2.6 Safe Torque Off (STO)2.6.1 Safe Torque Off (STO)Safe Torque Off is an option. To run Safe Torque Off,additional wiring for the frequency converter is required.Refer to VLT® Frequency Converters Safe Torque OffOperating Instructions for further information.2.7 Advantages2.7.1 Why Use a Frequency Converter forControlling Fans and Pumps?A frequency converter takes advantage of the fact thatcentrifugal fans and pumps follow the laws of propor-tionality for such applications. For further information, seechapter 2.7.3 Example of Energy Savings.2.7.2 Energy SavingsThe clear advantage of using a frequency converter forcontrolling the speed of fans and pumps lies in theelectricity savings. When comparing with alternativecontrol systems and technologies, a frequency converter isthe optimum energy control system for controlling fan andpump systems.120100806040200 20 40 60 80 100 120 140 160 180120100806040200 20 40 60 80 100 120 140 160 180Voume %Voume %INPUT POWER % PRESSURE %SYSTEM CURVEFAN CURVEABC130BA781.10ENERGYCONSUMEDIllustration 2.1 Energy Saved with Reduced Fan CapacitySYSTEM CURVEFAN CURVEPRESSURE%130BA780.10ABC02040608010012020 40 60 80 100 120 140 160 180VOLUME%Illustration 2.2 Fan Curves for Reduced Fan Volumes.Introduction Design Guide16 Danfoss A/S © Rev. 05/2014 All rights reserved. MG16C20222
