Danfoss VLT 6000 HVAC Series Quick Setup Manual

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Danfoss VLT 6000 HVAC Series Quick Setup Manual Manual pdf 11 page image

VLT ® 6000 HVACInstallation■ Electrical installation - earthing of control cablesGenerally speaking, control cables must be braidedscreened/armoured and the screen must beconnected by means of a cable clamp at bothends to the metal cabinet of the unit.The drawing below indicates how correct earthing iscarried out and what to be done if in doubt.Correct earthingControl cables and cables for serial communicationmust be fitted with cable clamps at both ends toensure the best possible electrical contactWrong earthingDo not use twisted cable ends (pigtails), since theseincrease the screen impedance at high frequencies.Protection with respect to earth potentialbetween PLC and VLTIf the earth potential between the frequency converterand the PLC (etc.) is different, electric noise mayoccur that will disturb the whole system. Thisproblem can be solved by fitting an equalisingcable, to be placed next to the control cable.Minimum cable cross-section: 16 mm 2 .For 50/60 Hz earth loopsIf very long control cables are used, 50/60 Hz earthloops may occur. This problem can be solved byconnecting one end of the screen to earth via a100nF capacitor (keeping leads short).Cables for serial communicationLow-frequency noise currents between two frequencyconverters can be eliminated by connecting one endof the screen to terminal 61. This terminal is connectedto earth via an internal RC link. It is recommendedto use twisted-pair cables to reduce the differentialmode interference between the conductors.■ Tightening-up torque and screw sizesThe table shows the torque required when fittingterminals to the frequency converter. For VLT6002-6032, 200-240 V, VLT 6002-6122, 380-460and 525-600 V the cables must be fastenedwith screws. For VLT 6042-6062, 200-240 Vand for VLT 6152-6550, 380-460 V, the cablesmust be fastened with bolts.These figures apply to the following terminals:91, 92, 93Mains terminals (Nos.) L1, L2, L396, 97, 98Motor terminals (Nos.) U, V, WEarth terminal (Nos.) 94, 95, 99MG.60.C7.02 - VLT is a registered Danfoss trademark 11