Danfoss VT2800 Series Design Manual

Contents

VLT ® 2800 Series411 Switching frequency(SWITCH FREQ.)Value:3000 - 14000 Hz (VLT 2803 - 2875) ✭ 4500 Hz3000 - 10000 Hz (VLT 2880 - 2882) ✭ 4500 HzFunction:The set value determines the switching frequency of theinverter. If the switching frequency is changed, this mayhelp to minimise possible acoustic noise from the motor.NB!:The output frequency of the frequency convertercan never assume a value higher than 1/10of the switching frequency.Description of choice:When the motor is running, the switching frequencyis adjusted in parameter 411 Switching frequencyuntil the frequency has been obtained at whichthe motor is as low-noise as possible.NB!:The switching frequency is reducedautomatically as a function of the load.See Temperature-Dependent SwitchingFrequency under Special Conditions .When LC-filter connected is selected in parameter412, the minimum switching frequency is 4.5 kHz.412 Variable switching frequency(VAR CARRIER FREQ.)Value:✭Without LC-filter (WITHOUT LC-FILTER) [2]LC-filter connected(LC-FILTER CONNECTED) [3]Function:The parameter must be set to LC-filter connectedif an LC-filter is connected between the frequencyconverter and the motor.Description of choice:The LC-filter connected [3] must be used if anLC-filter is connected between the frequencyconverter and the motor, as otherwise the frequencyconverter cannot protect the LC-filter.NB!:When the LC filter is selected the switchingfrequency is changed to 4.5 kHz.413 Overmodulation function(OVERMODULATION)Value:Off (OFF) [0]✭On (ON) [1]Function:This parameter allows connection of theovermodulation function for the output voltage.Description of choice:Off [0] means that there is no overmodulationof the output voltage, which means that torqueripple on the motor shaft is avoided. This canbe a good feature, e.g. on grinding machines.On [1] means that an output voltage can be obtainedwhich is greater than the mains voltage (up to 5 %).414 Minimum feedback, FB MIN(MIN. FEEDBACK)Value:-100,000.000 - par. 415 FB MAX ✭ 0.000Function:Parameter 414 Minimum feedback, FB MIN and 415Maximum feedback, FB MAX are used to scale thedisplay text to make it show the feedback signal in aprocess unit proportionally to the signal on the input.Description of choice:Set the value to be shown on the display as theminimum feedback signal value on the selectedfeedback input (parameters 308/314 Analogue inputs).415 Maximum feedback, FB MAX(MAX. FEEDBACK)Value:FB MIN - 100,000.000 ✭ 1500.000Function:See description of parameter 414 Minimumfeedback, FB MIN.Description of choice:Set the value to be shown on the display when themaximum feedback has been obtained on the selectedfeedback input (parameter 308/314 Analogue inputs).✭ = factory setting. () = display text [] = value for use in communication via serial communication portMG.28.E9.02 - VLT is a registered Danfoss trademark98