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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Example: Assume a 160 kW, 380–480 V AC drive at 25%load at 50% speed. Illustration 10.15 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 10.15 lists the typical acoustic noise values measuredat a distance of 1 m (9 ft) from the unit.Enclosure size dBA at full fan speedE1h–E4h 80Table 10.15 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.10.13 dU/dt ConditionsNOTICETo avoid the premature aging of motors that are notdesigned to be used with drives, such as those motorswithout phase insulation paper or other insulationreinforcement, Danfoss strongly recommends a dU/dtfilter or a sine-wave filter fitted on the output of thedrive. For further information about dU/dt and sine-wavefilters, see the Output Filters Design Guide.When a transistor in the inverter bridge switches, thevoltage across the motor increases by a dU/dt ratiodepending on:• The motor cable (type, cross-section, lengthshielded or unshielded).• Inductance.The natural induction causes an overshoot UPEAK in themotor voltage before it stabilizes itself at a leveldepending on the voltage in the intermediate circuit. Therise time and the peak voltage UPEAK affect the service lifeof the motor. In particular, motors without phase coilinsulation are affected if the peak voltage is too high.Motor cable length affects the rise time and peak voltage.For example, if the motor cable is short (a few meters), therise time and peak voltage are lower. If the motor cable islong (100 m (328 ft)), the rise time and peak voltage arehigher.Peak voltage on the motor terminals is caused by theswitching of the IGBTs. The drive complies with thedemands of IEC 60034-25 regarding motors designed to becontrolled by drives. The drive also complies with IEC60034-17 regarding Norm motors controlled by drives.High-power rangeThe power sizes in Table 10.16 to Table 10.21 at theappropriate mains voltages comply with the requirementsof IEC 60034-17 regarding normal motors controlled bydrives, IEC 60034-25 regarding motors designed to becontrolled by drives, and NEMA MG 1-1998 Part 31.4.4.2 forinverter fed motors. The power sizes in Table 10.16 toTable 10.21 do not comply with NEMA MG 1-1998 Part30.2.2.8 for general purpose motors.Electrical Installation Con... Design GuideMG22B102 Danfoss A/S © 05/2017 All rights reserved. 8710 10