Danfoss VLT AutomationDrive FC 302 Instruction Manual

Also see for VLT AutomationDrive FC 302: Service guide Programming guide Instruction manual Installation guide Operating guide

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Danfoss VLT AutomationDrive FC 302 Instruction Manual Manual pdf 28 page image

Shielding of cablesAvoid installation with twisted shield ends (pigtails). Theyspoil the shielding effect at higher frequencies. If breakingthe shield is necessary to install a motor isolator orcontactor, continue the shield at the lowest possible HFimpedance.Connect the motor cable shield to both the decouplingplate of the adjustable frequency drive and to the metalhousing of the motor.Make the shield connections with the largest possiblesurface area (cable clamp). Use the installation deviceswithin the adjustable frequency drive.Cable length and cross-sectionThe adjustable frequency drive has been EMC tested witha given length of cable. Keep the motor cable as short aspossible to reduce the noise level and leakage currents.Switching frequencyWhen adjustable frequency drives are used together withsine-wave filters to reduce the acoustic noise from amotor, the switching frequency must be set according to14-01 Switching Frequency.Term.no.96 97 98 99U V W PE1)Motor voltage 0–100% of AC linevoltage.3 wires out of motorU1 V1 W1 PE1) Delta-connectedW2 U2 V2 6 wires out of motorU1 V1 W1 PE1)Star-connected U2, V2, W2U2, V2, and W2 to be interconnectedseparately.Table 3.3 Terminal Connections1)Protected Ground ConnectionU1 V1 W1175ZA114.1196 97 98 96 97 98FC FCMotor MotorU2 V2 W2U1 V1 W1U2 V2 W2Figure 3.15 Y and Delta Terminal Configurations3.4.2 GroundingNote the following basic issues for electromagneticcompatibility (EMC) during installation:• Safety grounding: The adjustable frequency drivehas a high leakage current and must begrounded appropriately for safety reasons. Alwaysfollow local safety regulations.• High-frequency grounding: Keep the ground wireconnections as short as possible.Connect the different ground systems at the lowestpossible conductor impedance. Keep the conductor asshort as possible and use the greatest possible surface areafor the lowest possible conductor impedance.The metal cabinets of the different devices are mountedon the cabinet rear plate using the lowest possible HFimpedance. Doing so avoids different HF voltages forindividual devices and the risk of radio interferencecurrents running in connection cables between thedevices. The radio interference is reduced.To obtain a low HF impedance, use the fastening bolts ofthe devices as HF connection to the rear plate. Removeinsulating paint or similar from the fastening points.3.4.3 Extra Protection (RCD)ELCB relays, multiple protective grounding, or standardgrounding provide extra protection, if local safetyregulations are followed.In the case of a ground fault, a DC component develops inthe fault current.If using ELCB relays, observe local regulations. Relays mustbe suitable for protection of 3-phase equipment with abridge rectifier and for a brief discharge on power-up.Installation Instruction Manual26 Danfoss A/S © Rev. 2014-02-07 All rights reserved. MG37A22233