Excessive dust particle levels are often found on instal-lation cabinets 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 frequency converter. ContactDanfoss for more information.2.6 Vibration and ShockThe frequency converter has been tested according to theprocedure based on the following standards:The frequency converter complies with requirements thatexist for units mounted on the walls and floors ofproduction premises, as well as in panels bolted to walls orfloors.• IEC/EN 60068-2-6: Vibration (sinusoidal) - 1970• IEC/EN 60068-2-64: Vibration, broad-band random2.7 Safe Torque Off (STO)STO is an option. To run STO, additional wiring for thefrequency converter is required. Refer to VLT® FrequencyConverters Safe Torque Off Operating Instructions for furtherinformation.2.8 Frequency Converter Benefits2.8.1 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 fans and pumps. For further information,see the text and Illustration 2.1.2.8.2 The Clear Advantage - Energy SavingsThe clear advantage of using a frequency converter forcontrolling the speed of fans or pumps lies in theelectricity savings.When comparing with alternative control systems andtechnologies, a frequency converter is the optimum energycontrol system for controlling fan and pump systems.SYSTEM CURVEFAN CURVEPRESSURE%130BA780.10ABC02040608010012020 40 60 80 100 120 140 160 180VOLUME%Illustration 2.1 Fan Curves (A, B and C) for Reduced FanVolumesMore than 50% energy savings can be obtained in typicalapplications when a frequency converter is used to reducefan capacity to 60%.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 2.2 Energy SavingsIntroduction Design Guide14 Danfoss A/S © Rev. 06/2014 All rights reserved. MG20Z20222
