The cascade controller options can control a mix ofvariable speed and fixed speed pumps.100% 100% 200% 200%130BA594.12Relay 1Relay 2Relay 10Built-in 1 VSP + 2 FSPparameter group 25-** Cascade ControllerMCO 101 1 VSP + 5 FSPparameter group 25-** Cascade ControllerMCO 102 1 VSP + 8 FSPparameter group 25-** Cascade ControllerIllustration 3.27 Application OverviewBuilt-in -MCO 1011 to 6 VSP + 1 to 5 FSP(maximum 6 pumps)parameter group 27-** Cascade CTL OptionMCO 1021 to 8 VSP + 1 to 7 FSP(maximum 8 pumps)parameter group 27-** Cascade CTL OptionIllustration 3.28 Application OverviewBuilt-in -MCO 101 6 VSPparameter group 27-** Cascade CTL OptionMCO 102 8 VSPparameter group 27-** Cascade CTL OptionIllustration 3.29 Application OverviewVSP = Variable speed pump (directly connected to thefrequency converter)FSP = Fixed speed pump (the motor could be connected viacontactor, soft starter or star/delta starter)3.7.4 Brake ResistorsIn applications where the motor is used as a brake, energyis generated in the motor and sent back into thefrequency converter. If the energy cannot be transportedback to the motor, it increases the voltage in thefrequency converter DC line. In applications with frequentbraking and/or high inertia loads, this increase may lead toan overvoltage trip in the frequency converter and, finally,a shut down. Brake resistors are used to dissipate theexcess energy resulting from the regenerative braking. Theresistor is selected based on its ohmic value, its powerdissipation rate and its physical size. Danfoss offers a widevariety of different resistors that are specially designed toDanfoss frequency converters. See chapter 3.4.12 BrakeResistor Calculation for dimensioning of brake resistors. Forordering numbers refer to chapter 6.2 Options, Accessories,and Spare Parts.3.7.5 Sine-wave FiltersWhen a motor is controlled by a frequency converter,resonance noise is heard from the motor. This noise, whichis the result of the motor design, arises every time aninverter switch in the frequency converter is activated. Thefrequency of the resonance noise thus corresponds to theswitching frequency of the frequency converter.System Integration Design Guide70 Danfoss A/S © 09/2014 All rights reserved. MG20N60233
