CT100 series inverters Installation and wiring
45
certain electromagnetic environment.
All the connections to the control terminals must use shielded wire. And the
shield layer of the wire must ground near the wire entrance of the inverter. The
ground mode is 360 degree annular connection formed by cable clips. It is strictly
prohibitive to connect the twisted shielding layer to the ground of the inverter,
which greatly decreases or loses the shielding effect.
Power supply wiring: The shielding layer of power supply incoming cables of the
inverter shall be grounded reliably. It is strictly prohibitive to route the power
cables and control cables in parallel.
Device categorization: There are different electric devices in the same
distribution system, which have different ability of emitting and withstanding
electromagnetic noise. Therefore, it needs to categorize these devices into
strong noise device and noise sensitive device. The same kind of devices needs
to be placed in the same area, and the distance between devices in different
categories needs to be more than 20cm.
Wiring in the control cabinet: During wiring, signal cables and power cables need
to be arranged in different areas. It is strictly prohibitive to arrange them in
parallel or interlacement at a close distance (less than 20cm) or tie them together.
If the signal cables have to cross the power cables, they need to be arranged in
90 degree angle.
The inverter must be grounded safely and reliably in operation. Grounding has
the priority in all EMC methods because it does not only ensure the safety of
equipment and persons, but also it is the simplest, most effective and lowest-cost
solution for EMC problems.
Three categories of grounding: special pole grounding, common pole grounding
and series-wound grounding. Different control system needs to use special pole
grounding, different devices in the same control system needs to use common
pole grounding, and different devices connected by the same power cables
needs to use series-wound grounding.
Leakage current includes cable leakage current and ground leakage current. The
size depends on the distributed capacitance and the carrier frequency of the
inverter in distribution.
The ground leakage current refers to the leakage current flowing through the
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