68 Guidelines for planning the electrical installationAdditional data for calculating the rise time and the peak line-to-line voltageThe diagrams below show the relative peak line-to-line voltage and rate of change ofvoltage as a function of the motor cable length with and without a du/dt filter in use.To calculate the actual peak voltage for a certain cable length read the relative ÛLL /UNvalue from the appropriate diagram and multiply it by the nominal supply voltage (UN ).To calculate the actual voltage rise time for a certain cable length read the relative valuesÛLL/UN and (du/dt)/U N from the appropriate diagram. Multiply the values by the nominalsupply voltage (U N ) and substitute into equation t = 0.8 · ÛLL/(du/dt).Additional note for sine filtersSine filters protect the motor insulation system. Therefore, the du/dt filter can be replacedwith a sine filter. The peak phase-to-phase voltage with the sine filter is approximately1.5 · UN .Additional note for common mode filtersCommon mode filters are available as plus code option +E208.600 V < UN < 690 V Reinforced: ÛLL = 1800 V + N + du/dt + CMFReinforced: ÛLL = 2000 V,0.3 microsecond rise time***N + CMF***If the intermediate DC circuit voltage of the drive is increased from the nominal level by resistor braking,check with the motor manufacturer if additional output filters are needed in the applied drive operationrange.Drive with du/dt filter Drive without du/dt filterI Motor cable lengthÛLL /UN Relative peak line-to-line voltagedu/dt /U N Relative du/dt valueNote: ÛLL and du/dt values are approximately 20% higher with resistor braking.Nominal AC supplyvoltageRequirement forMotor insulation system ABB du/dt filter, insulated N-end bearing and ABBcommon mode filter100 200 3000.00.51.01.52.02.53.0l (m)du/dtUN-------------(1/μs)ÛLL/UNÛLL /UNl (m)du/dtUN-------------(1/μs)1.02.05.04.03.01.52.53.54.5100 200 3005.5
