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

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Danfoss VLT AQUA Drive FC 202 Design Manual Manual pdf 174 page image

10.11 EfficiencyEfficiency of the drive (ηVLT)The load on the drive has little effect on its efficiency. Ingeneral, the efficiency is the same at the rated motorfrequency fM,N, whether the motor supplies 100% of therated shaft torque or only 75%, in case of part loads.The efficiency of the drive does not change even if otherU/f characteristics are selected. However, the U/f character-istics influence the efficiency of the 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 (98 ft).Drive efficiency calculationCalculate the efficiency of the drive at different speeds andloads based on Figure 10.16. The factor in this graph mustbe multiplied with the specific efficiency factor listed in thespecification tables in chapter 7.1 Electrical Data, 380–480 Vand chapter 7.2 Electrical Data, 525–690 V .1.00.990.980.970.960.950.930.920% 50% 100% 200%0.94Relative Efficiency130BB252.111.01150%% Speed100% load 75% load 50% load 25% loadFigure 10.16 Typical Efficiency CurvesExample: Assume a 160 kW, 380–480 V AC drive at 25%load at 50% speed. Figure 10.16 shows 0.97 - ratedefficiency for a 160 kW drive is 0.98. The actual efficiency isthen: 0.97x 0.98=0.95.Efficiency of the motor (ηMOTOR)The efficiency of a motor connected to the drive dependson magnetizing level. In general, the efficiency is as goodas with mains operation. The efficiency of the motordepends on the type of motor.In the range of 75–100% of the rated torque, the efficiencyof the motor is practically constant, both when the drivecontrols it and when it runs directly on the mains.In small motors, the influence from the U/f characteristicon efficiency is marginal. However, in motors from 11 kW(14.75 hp) and up, the advantages are significant.Typically the switching frequency does not affect theefficiency of small motors. Motors from 11 kW (14.75 hp)and up have their efficiency improved (1–2%) because theshape of the motor current sine-wave is almost perfect athigh switching frequency.Efficiency of the system (ηSYSTEM)To calculate system efficiency, the efficiency of the drive(ηVLT) is multiplied by the efficiency of the motor (ηMOTOR):ηSYSTEM=ηVLT x ηMOTOR10.12 Acoustic NoiseThe acoustic noise from the drive comes from 3 sources:• DC intermediate circuit coils.• Internal fans.• RFI filter choke.Table 10.24 lists the typical acoustic noise values measuredat a distance of 1 m (9 ft) from the unit.Enclosure size dBA at full fan speedD1h/D3h/D5h/D6h 73D2h/D4h/D7h/D8h 75E1h–E4h 80Table 10.24 Acoustic NoiseTest results performed according to ISO 3744 for audiblenoise magnitude in a controlled environment. Noise tonehas been quantified for engineering data record ofhardware performance per ISO 1996-2 Annex D.A new fan control algorithm for E1h-E4h enlosure sizeshelps improve audible noise performance by allowing theoperator to select different fan operation modes based onspecific conditions. For more information, seeparameter 30-50 Heat Sink Fan Mode.Electrical Installation Con... VLT® AQUA Drive FC 202172 Danfoss A/S © 01/2018 All rights reserved. MG22B2221010