Danfoss VLT 8000 AQUA series Operating Instructions Manual

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Contents

Danfoss VLT 8000 AQUA series Operating Instructions Manual Manual pdf 10 page image

VLT ® 8000 AQUA■ Control principleA frequency converter rectifies AC voltage frommains into DC voltage, after which this DCvoltage is converted into a AC current with avariable amplitude and frequency.The motor is thus supplied with variable voltage andfrequency, which enables infinitely variable speedcontrol of three-phased, standard AC motors.1. Mains voltage3 x 200 - 240 V AC, 50 / 60 Hz.3 x 380 - 480 V AC, 50 / 60 Hz.3 x 525 - 600 V AC, 50 / 60 Hz.3 x 525 - 690 V AC, 50 / 60 Hz.2. RectifierA three-phase rectifier bridge that rectifies ACcurrent into DC current.3. Intermediate circuitDC voltage = 1.35 x mains voltage [V].4. Intermediate circuit coilsEven out the intermediate circuit voltage and reducethe harmonic current feedback to the mains supply.5. Intermediate circuit capacitorsEven out the intermediate circuit voltage.6. InverterConverts DC voltage into variable AC voltagewith a variable frequency.7. Motor voltageVariable AC voltage, 0-100% of mains supply voltage.8. Control cardThis is where to find the computer that controlsthe inverter which generates the pulse pattern bywhich the DC voltage is converted into variableAC voltage with a variable frequency.■ AEO - Automatic Energy OptimizationNormally, the U/f characteristics have to be set on thebasis of the expected load at different frequencies.However, knowing the load at a given frequency in aninstallation is often a problem. This problem can besolved by using a VLT 8000 AQUA with its integralAutomatic Energy Optimization (AEO), which ensuresoptimum energy utilization. All VLT 8000 AQUA unitsfeature this function as a factory setting, i.e. it isnot necessary to adjust the frequency converter U/fratio in order to obtain maximum energy savings.In other frequency converters, the given load andvoltage/frequency ratio (U/f) must be assessed to carryout correct setting of the frequency converter.Using Automatic Energy Optimization (AEO), youno longer need to calculate or assess the systemcharacteristics of the installation, since Danfoss VLT8000 AQUA units guarantee optimum, load-dependentenergy consumption by the motor at all times.The figure on the right illustrates the workingrange of the AEO function, within which energyoptimization is enabled.If the AEO function has been selected in parameter 101,Torque characteristics, this function will be constantlyactive. If there is a major deviation from the optimum U/fratio, the frequency converter will quickly adjust itself.Advantages of the AEO function• Automatic energy optimization• Compensation if an oversize motor is used• AEO matches operations to daily orseasonal fluctuationsMG.83.A2.02 - VLT is a registered Danfoss trademark10