Danfoss VLT AQUA Drive FC 202 Design Manual

Also see for VLT AQUA Drive FC 202: Service guide Installation guide Installation guide Operating guide Installation guide

Contents

CAUTIONConnection to PC is carried out via a standard host/deviceUSB cable.The USB connection is galvanically isolated from thesupply voltage (PELV) and other high-voltage terminals.The USB connection is not galvanically isolated fromprotection earth. Use only isolated laptop/PC as connectionto the USB connector on the frequency converter or anisolated USB cable/converter.3.2 EfficiencyEfficiency of the frequency converter (ηVLT)The load on the frequency converter has little effect on itsefficiency. In general, the efficiency is the same at therated motor frequency fM,N, even if the motor supplies100% of the rated shaft torque or only 75%, in case of partloads.The efficiency of the frequency converter does not changeeven if other U/f characteristics are chosen.However, the U/f characteristics influence the efficiency ofthe motor.The efficiency declines slightly when the switchingfrequency is set to a value of above 5 kHz. The efficiency isslightly reduced when the mains voltage is 480 V, or if themotor cable is longer than 30 m.Frequency converter efficiency calculationCalculate the efficiency of the frequency converter atdifferent speeds and loads based on Illustration 3.2. Thefactor in this graph must be multiplied with the specificefficiency factor listed in the specification tables in3.1.1 Mains Supply 3x380-480 V AC and 3.1.2 Mains Supply3x525-690 V AC.1.00.990.980.970.960.950.930.920% 50% 100% 200%0.94Relative Efficiency130BB252.111.01150%% Speed100% load 75% load 50% load 25% loadIllustration 3.2 Typical Efficiency CurvesExample: Assume a 160 kW, 380–480 V AC frequencyconverter at 25% load at 50% speed. Illustration 3.2 shows0.97 - rated efficiency for a 160 kW frequency converter is0.98. The actual efficiency is then: 0.97x 0.98=0.95.Efficiency of the motor (ηMOTOR)The efficiency of a motor connected to the frequencyconverter depends on magnetizing level. In general, theefficiency is as good as with mains operation. Theefficiency of the motor depends on the type of motor.In the range of 75–100% of the rated torque, the efficiencyof the motor is practically constant, both when thefrequency converter controls it and when it runs directlyon mains.In small motors, the influence from the U/f characteristicon efficiency is marginal. However, in motors from 11 kWand up, the advantages are significant.In general, the switching frequency does not affect theefficiency of small motors. Motors from 11 kW and up havetheir efficiency improved (1–2%) because the shape of themotor current sine wave is almost perfect at highswitching frequency.Efficiency of the system (ηSYSTEM)To calculate the system efficiency, the efficiency of thefrequency converter (ηVLT) is multiplied by the efficiency ofthe motor (ηMOTOR):ηSYSTEM=ηVLT x ηMOTOR3.3 Acoustic NoiseThe acoustic noise from the frequency converter comesfrom three sources:1. DC intermediate circuit coils.2. Integral fan.3. RFI filter choke.The typical values measured at a distance of 1 m from theunit:Enclosure Full fan speed [dBA]N110 71N132 71N160 72N200 74N250 75N315 73E1/E2 * 74E1/E2 ** 83F1/F2/F3/F4 80F8/F9/F10/F11/F12/F13 84.5* 315 kW, 380–480 VAC. 450 kW and 500 kW, 525–690 VAC only.** Remaining E1+E2 power sizes.Table 3.9 Acoustic Noise LevelsSelection VLT® AQUA Drive FC 202 Design GuideMG20Z102 - VLT® is a registered Danfoss trademark 513 3