Danfoss VLT FC 100 Service Manual

Also see for VLT FC 103: Service guide Installation guide Installation guide Operating guide Installation guide

Contents

Danfoss VLT FC 100 Service Manual Manual pdf 61 page image

5 Adjustable Frequency Drive and Motor Applications5.1 Torque Limit, Current Limit, andUnstable Motor OperationExcessive loading of the adjustable frequency drive couldresult in warning or tripping on torque limit, overcurrent,or inverter time. Tripping is not a concern if the adjustablefrequency drive is properly sized for the application andintermittent load conditions cause anticipated operation intorque limit or an occasional trip. However, nuisance orunexplained occurrences are sometimes the result ofimproperly setting specific parameters. The followingparameters are important in matching the adjustablefrequency drive to the motor for optimum operation.These settings need careful attention.1-03 Torque Characteristics sets the mode in whichthe adjustable frequency drive operates.Parameters 1-20 Motor Power [kW] to1-29 Automatic Motor Adaptation (AMA) match theadjustable frequency drive to the motor andadapt to the motor characteristics.4-17 Torque Limit Generator Mode and 14-25 TripDelay at Torque Limit set the torque controlfeatures of the adjustable frequency drive for theapplication.1-00 Configuration Mode sets the adjustable frequencydrive for open-loop or closed-loop operation or torquemode operation. In a closed-loop configuration, a feedbacksignal controls the adjustable frequency drive speed. Thesettings for the PID controller play a key role for stableoperation in closed-loop, as described in the InstructionManual. In open-loop, the adjustable frequency drivecalculates the torque requirement based on currentmeasurements of the motor.1-03 Torque Characteristics sets the adjustable frequencydrive for constant or variable torque operation. It isimperative that the correct torque characteristic is selected,based on the application. If the load type is constanttorque and variable torque is selected, it may be verydifficult or impossible for the adjustable frequency drive tostart the load. Consult the factory if uncertain about thetorque characteristics of an application.Parameters 1-20 Motor Power [kW] to 1-25 Motor NominalSpeed configure the adjustable frequency drive for theconnected motor. These parameters are motor power,voltage, frequency, current, and rated motor speed.Accurate setting of these parameters is crucial. Enter themotor data required as listed on the motor nameplate. Foreffective and efficient load control, the adjustablefrequency drive relies on this information for calculatingthe output waveform in response to the changingdemands of the application.1-29 Automatic Motor Adaptation (AMA) activates theautomatic motor adaptation (AMA) function. When AMA isperformed, the adjustable frequency drive measures theelectrical characteristics of the motor and sets variousadjustable frequency drive parameters based on thefindings. Two key parameter values set by this function arestator resistance and main reactance, 1-30 Stator Resistance(Rs) and 1-35 Main Reactance (Xh). If the motor operation isunstable, perform AMA. AMA can only be performed onsingle motor applications within the programming rangeof the adjustable frequency drive. Consult the InstructionManual for more on this function.1-30 Stator Resistance (Rs) and 1-35 Main Reactance (Xh), asstated, are set by the AMA function, values supplied by themotor manufacturer, or left at the factory default values.Never adjust these parameters to random values even if itseems to improve operation. Such adjustments can resultin unpredictable operation under changing conditions.4-16 Torque Limit Motor Mode sets the limit for adjustablefrequency drive torque. The factory setting is 160% for FC302 series and 110% for/seriesFC 102FC 202 and vary withmotor power setting. For example, an adjustable frequencydrive programmed to operate a small motor yields ahigher torque limit value than one programmed to operatea larger size motor. It is important that this value is not settoo low for the requirements of the application. In somecases, it is desirable to have a torque limit set at a lesservalue. This offers protection for the application in that theadjustable frequency drive limits the torque. A highertorque may be required at initial startup, which couldcause nuisance tripping.Adjustable Frequency Drive ... Service ManualMG94A222 Danfoss A/S © Rev. 2014-02-10 All rights reserved. 595 5