Danfoss VLT 8000 AQUA Instalační příručka stáhnout pdf (Strana 13)

VLT® 8000 AQUA

Installation

■ Earthing/Grounding of shielded/armored

control cables

Generally speaking, control cables must be shielded/

armored and the shield must be connected by

means of a cable clamp at both ends to the

metal cabinet of the unit.

The drawing below indicates how correct

earthing/grounding is carried out.

Correct earthing/grounding

Control cables and cables for serial communication

must be fitted with cable clamps at both ends to

ensure the best possible electrical contact.

rong earthing/grounding

Do not use twisted cable ends (pigtails), since these

increase the shield impedance at high frequencies.

rotection with respect to ground potential

between PLC and AFD

If the ground potential between the AFD and the PLC

(etc.) is different, electric noise may occur that will

disturb the whole system. This problem can be solved

by fitting an equalizing cable, to be placed next to the

control cable. Minimum cable cross-section: 8 AWG.

or 50/60 Hz ground loops

If very long control cables are used, 50/60 Hz

ground loopsmay occur that will disturb the whole

system. This problem can be solved by connecting

one end of the shield to via a ground 100nF

capacitor (keeping leads short).

ables for serial communication

Low-frequency noise currents between two AFD can

be eliminated by connecting one end of the shield

to terminal 61. This terminal is connected to ground

via an internal RC link. It is recommended to use

twisted-pair cables to reduce the differential mode

interference between the conductors.

MG.80.A6.22 - VLT is a registered Danfoss trademark

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Danfoss VLT 8000 AQUA Instalační příručka Strana 13