Danfoss VLT HVAC Drive FC 102 Operating Instructions Manual

Also see for VLT HVAC Drive FC 102: Operating instructions Service guide Programming guide Installation guide Installation guide

Contents

4.1.2 GroundingTo obtain electromagnetic compatibility (EMC), considerthe following during installation:• Safety grounding: For safety reasons, ground thefrequency converter appropriately due to its highleakage current. Apply local safety regulations.• High-frequency grounding: Keep the ground wireconnections as short as possible.Connect the different ground systems at the lowestpossible conductor impedance. The lowest possibleconductor impedance is obtained by keeping theconductor as short as possible and by using the greatestpossible surface area.The metal cabinets of the different devices are mountedon the cabinet rear plate using the lowest possible HFimpedance. Different HF voltages are then avoided for theindividual devices. Also the risk of radio interferencecurrents running in connection cables that may be usedbetween the devices is avoided. The radio interference hasbeen reduced.To obtain a low HF impedance, use the fastening bolts ofthe devices as HF connection to the rear plate. It isnecessary to remove insulating paint or similar from thefastening points.4.1.3 Extra Protection (RCD)If local safety regulations are complied with, ELCB relays,multiple protective earthing, or grounding can be used asextra protection.A ground fault may cause a DC component to develop inthe fault current.If ELCB relays are used, observe local regulations. Relaysmust be suitable for the protection of 3-phase equipmentwith a bridge rectifier and for a brief discharge on power-up.See also Special Conditions in the product relevant designguide.4.1.4 RFI SwitchMains supply isolated from groundIf the frequency converter is supplied from an isolatedmains source (IT mains, floating delta and grounded delta)or TT/TN-S mains with grounded leg, turn off the RFIswitch via 14-50 RFI Filter on both the frequency converterand the filter. For further reference, see IEC 364-3.Set 14-50 RFI Filter to [ON]• If optimum EMC performance is needed.• Parallel motors are connected.• The motor cable length is above 25 m.In OFF, the internal RFI capacities (filter capacitors)between the enclosure and the intermediate circuit are cutoff to avoid damage to the intermediate circuit and toreduce the ground capacity currents (according to IEC61800-3).Also refer to the Application Note VLT on IT Mains. It isimportant to use isolation monitors suited for powerelectronics (IEC 61557-8).4.1.5 TorqueTighten all electrical connections with the correct torque.Too low or too high torque results in a bad electricalconnection. To ensure correct torque, use a torque wrench.176FA247.12Nm/in-lbs-DC 88 +DC 89R/L1 91 S/L2 92 T/L3 93U/T1 96 V/T2 97W/T3Illustration 4.10 Tighten Bolts with a Torque WrenchEnclosuresizesTerminal Torque [Nm] (in-lbs) Bolt sizeE MainsMotorLoad sharing19–40(168–354) M10Brake 8.5–20.5(75–181) M8Electrical Installation Operating InstructionsMG11F502 Danfoss A/S © 08/2014 All rights reserved. 434 4