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4.1.2 Selection of Control, Signal and Communication Cables
The recommended cable section area and specification:
●
Analog input and output cable: whole shielded twisted pair line, section area 1.5
～
2.5 mm
2
●
Digital input and output cable: whole shielded twisted pair line, section area 0.5
～
1.5 mm
2
●
Communication wire: Special communication wires or whole shielded twisted pair line, section area 0.5
～
1.5 mm
2
After finish wiring, please check:
●
All the wiring is correct.
●
Any short circuit or grounding short circuit of the terminals and wiring
●
Any missing wiring
●
Whether the insulation distance and creepage distance meet the requirements.
4.2 Primary Wiring
Attention!
●
High quality single shielded twisted pair line or multiple shielded twisted pair line should be selected for
control, signal and communication cable.
●
Control, signal, communication, power wires and power cables should be routed separately in different
cable channel and bridge duct. In case of mix routing, the distance between the secondary wires and
power cables should be kept larger than 30cm.
●
It is not permitted that power wires or ground wires share a common shielded wire with signal wires.
●
Control, signal and communication cables should be laid in the corner and the zero electric potential to
improve the capability of anti-interference.
●
Cables for different kinds of signals must be cross routing.
●
Shielding layers should connect to ground with single terminal in VFD side. Shielding layer to terminal
should be short as possible.
●
For diminishing the electric potentials interference between different components, a electric potential
balance cable should be laid parallel to control wires, and the section area of wires must be 16mm
2
.
Typical wiring diagram of primary circuit is shown as Figure 4-1. The power room and its wiring cables are
supplied by customer. Inside the power room, protection for motor such as inverse time over-current, grounding
and arrester etc.should be set. According to the short-circuit capacity of motor, a differential protection might be
set too. Due to AC-DC-AC topology of
SINUS MV
VFD, the amplitude, frequency and phase of input and output of
VFD are different; the differential protection entry cable of current transducer should be mounted in the output side
of VFD.
Beside those Standard protections, interlock between power cabinet and VFD should be set. When the VFD has
fault, closing of breaker QF is ineffective. And the breaker QF will be open automatically while VFD has fault.
