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VLT
®
8000 AQUA
■
Earthing/Grounding of screened/armoured
control cables
Generally speaking, control cables must be screened/
armoured and the screen 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.
Wrong earthing/grounding
Do not use twisted cable ends (pigtails), since these
increase the screen impedance at high frequencies.
Protection with respect to earth potential
between PLC and frequency converter
If the earth potential between the frequency converter
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.
For 50/60 Hz earth loops
If very long control cables are used, 50/60 Hz
earth loopsmay occur that will disturb the whole
system. This problem can be solved by connecting
one end of the screen to via an earth 100nF
capacitor (keeping leads short).
Cables for serial communication
Low-frequency noise currents between two frequency
converter can be eliminated by connecting one end of
the screen to terminal 61. This terminal is connected
to earth via an internal RC link. It is recommended
to use twisted-pair cables to reduce the differential
mode interference between the conductors.
MG.83.A2.02 - VLT is a registered Danfoss trademark
64
Содержание VLT 8000 AQUA series
Страница 29: ...VLT 8000 AQUA Introduction TYPE CODE Table Ordering form MG 83 A2 02 VLT is a registered Danfoss trademark 29 ...
Страница 52: ...VLT 8000 AQUA Mechanical dimensions MG 83 A2 02 VLT is a registered Danfoss trademark 52 ...
Страница 60: ...VLT 8000 AQUA All enclosure types VLT 8152 8652 380 480 V MG 83 A2 02 VLT is a registered Danfoss trademark 60 ...
Страница 63: ...VLT 8000 AQUA Installation MG 83 A2 02 VLT is a registered Danfoss trademark 63 ...