Danfoss VLT AAF006 Operating Instructions Manual

Also see for VLT AAF006: Service manual

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Danfoss VLT AAF006 Operating Instructions Manual Manual pdf 21 page image

4.2.4 Extra Protection (RCD)ELCB, RCD, GFCI relays or multiple protective groundingsare often used as extra protection, or needed to providecompliance with local safety regulations. In case of aground fault, a DC component may develop in the faultcurrent. Observe local regulations when using ELCB relays.To reassure effective protection and unintended tripping ofprotective relays, all relays must be suitable for protectionof 3-phase equipment with active current infeed and for abrief discharge during power-up. Use a relay type withadjustable trip amplitude and time characteristics. Select acurrent sensor with sensitivity of more then 200 mA andnot less than 0.1 s operation time.4.2.5 RFI SwitchMains supply isolated from ground (IT mains)If the active filter is supplied from an isolated mains source(IT mains, floating delta and grounded delta) or TT/TN-Smains with grounded leg, the RFI switch is recommendedto be turned off (OFF) 1) via 14-50 RFI Filter on the unit.For further reference, see IEC 364-3. In OFF mode, theinternal RFI capacities between the chassis and theintermediate circuit are cut off to avoid damage to theintermediate circuit. Refer to the application note VLT® onIT mains. It is important to use isolation monitors that arecapable for use together with power electronics (IEC61557-8).NOTICEMarine grids are typically IT type grids.4.2.6 TorqueCorrect torque is imperative for all electrical connections.Incorrect torque results in a bad electrical connection.Torque values are provided in Table 4.3.Enclosure size Torque Bolt sizeD 19 Nm (168 in.-lbs.) M10E 19 Nm (168 in.-lbs.) M10Table 4.3 Correct Torque ValuesUse a torque wrench to ensure correct torque.176FA247.12Nm/in-lbs-DC 88 +DC 89R/L1 91 S/L2 92 T/L3 93U/T1 96 V/T2 97W/T3Illustration 4.4 Use a Torque Wrench to Tighten the Bolts4.2.7 Current Transformer (CT)The filter operates in close loop operation by receivingcurrent signals for external current transformers. Thereceived signal is processed and the filter reacts accordingto programmed actions.CAUTIONIncorrect current transformer connection, installation orconfiguration leads to unintended and uncontrollablebehaviour of the filter.NOTICEThe current transformers are not part of the filterpackage and must be purchased separately.CT specificationThe active filter supports most CTs. The CTs must have thefollowing specifications:Technical specification of active filter, passive CTRMS Maximum measured RMS currentAccuracy 0.5% or better (Class 0.5)Secondary ratedcurrent1A or 5A (5A is recommended)Set-up via hardwareRated frequency 50/60 HzRated power/burden See Table 4.5 (AAF burden equals 2 mΩ)Table 4.4 CT SpecificationsElectrical Installation Operating Instructions18 Danfoss A/S © 09/2014 All rights reserved. MG90V30244