Danfoss VLT AQUA Drive FC 202 Design Manual

Also see for VLT AQUA Drive FC 202: Service guide Installation guide Installation guide Operating guide Installation guide

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Danfoss VLT AQUA Drive FC 202 Design Manual Manual pdf 41 page image

• The same cascade controller hardware goes forthe entire power range up to 1.2 MW.• Up to 8 pumps in standard cascade set-up. Up to8 pumps in master/slave set-up.6.3 Motion Control and Relay CardsThis section describes the motion control and relay cardoptions that are available with the VLT® AQUA Drive FC202 series. For ordering numbers, refer tochapter 13.2 Ordering Numbers for Options and Accessories.6.3.1 VLT® Extended Relay Card MCB 113The VLT® Extended Relay Card MCB 113 adds inputs/outputs for increased flexibility.• 7 digital inputs.• 2 analog outputs.• 4 SPDT relays.• Meets NAMUR recommendations.• Galvanic isolation capability.6.4 Brake ResistorsIn applications where the motor is used as a brake, energyis generated in the motor and sent back into the drive. Ifthe energy cannot be transported back to the motor, itincreases the voltage in the drive DC line. In applicationswith frequent braking and/or high inertia loads, thisincrease can lead to an overvoltage trip in the drive and,finally, a shutdown. Brake resistors are used to dissipatethe excess energy resulting from the regenerative braking.The resistor 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 drives. For ordering numbers and moreinformation on how to dimension brake resistors, refer tothe VLT® Brake Resistor MCE 101 Design Guide.6.5 Sine-wave FiltersWhen a drive controls a motor, resonance noise is heardfrom the motor. This noise, which is the result of the motordesign, occurs every time an inverter switch in the drive isactivated. The frequency of the resonance noise thuscorresponds to the switching frequency of the drive.Danfoss supplies a sine-wave filter to dampen the acousticmotor noise. The filter reduces the ramp-up time of thevoltage, the peak load voltage (UPEAK), and the ripplecurrent (ΔI) to the motor, which means that current andvoltage become almost sinusoidal. The acoustic motornoise is reduced to a minimum.The ripple current in the sine-wave filter coils also causessome noise. Solve the problem by integrating the filter in acabinet or enclosure.For ordering numbers and more information on sine-wavefilters, refer to the Output Filters Design Guide.6.6 dU/dt FiltersDanfoss supplies dU/dt filters which are differential mode,low-pass filters that reduce motor terminal phase-to-phasepeak voltages and reduce the rise time to a level thatlowers the stress on the insulation at the motor windings.This is a typical issue with set-ups using short motorcables.Compared to sine-wave filters, the dU/dt filters have a cut-off frequency above the switching frequency.For ordering numbers and more information on dU/dtfilters, refer to the Output Filters Design Guide.6.7 Common-mode FiltersHigh-frequency common-mode cores (HF-CM cores) reduceelectromagnetic interference and eliminate bearingdamage by electrical discharge. They are special nanocrys-talline magnetic cores that have superior filteringperformance compared to regular ferrite cores. The HF-CMcore acts like a common-mode inductor between phasesand ground.Installed around the 3 motor phases (U, V, W), thecommon mode filters reduce high-frequency common-mode currents. As a result, high-frequency electromagneticinterference from the motor cable is reduced.For ordering numbers refer to the Output Filters DesignGuide.Options and Accessories Ove... Design GuideMG22B222 Danfoss A/S © 01/2018 All rights reserved. 396 6