SHENZHEN INVT ELECTRIC CO., LTD. CHV160 Operation Manual
25
360 trombone connection formed by cable clips. It is strictly prohibitive to twist the shielding
layer into braid and to connect it to the ground of inverter, which greatly decreases the
shielding effect and even lose the shielding effect.
The wires connecting the inverter and motor should be shielding wires or go through
separated cable tray. The shielding layer of motor wires or one end of the metal shell of the
cable tray should be connected to the ground and another end should be connected to the
motor enclosure. In the meantime, installing a noise filter can reduce greatly the
electromagnetic noise.
4.7.3.2 On-site Wire Arrangement
Power supply cable arrangement: the power supply cable of different control system is
connected to the transformer independently. Normally it is 5 core wires, three of which are live
wires, one of which is the neutral wire, and one of which is the earth wire. It is strictly
prohibitive to the neutral and the earth wire is one wire.
Device categorization: Generally there are different electric devices contained in one
control cabinet, such as inverter, electric wave filter, PLC and instrument and so on, which
have different ability of emitting and withstanding electromagnetic noise. Therefore, it is
necessary to categorize these devices into strong noise device and noise sensitive device.
The same category devices should be installed at the same area, and the distance between
different category devices should be more than 20cm.
Wire Arrangement inside the control panel: generally there are signal wire (light current)
and power cable (strong current) in one cabinet. For the inverter, the power cables are
categorized into incoming cable and outgoing cable. Signal wires can be easily interfered by
power cables and thus make the equipment malfunction. Therefore, when wire arrangement,
signal wires and power cables should be arranged in different area, it is strictly prohibitive to
arrange them in parallel or interlacement at a close distance (less than 20cm), and even to tie
them together. If the signal wires have to cross the power cables, they should be arranged in
90 angles. Power incoming cables and outgoing cables should not either be arranged in
interlacement or tied together, especially for installing noise filter; otherwise the distributed
capacitances of its incoming power cable and outgoing power cable can be coupling each
other, consequently making it out of function.
4.7.3.3 Earth Connection
Inverter must be ground connected safely and securely when in operation. As it does not
only ensure the safety of equipment and persons, but also is the simplest, most effective and
lowest cost solution for EMC problem. Grounding is the top priority.
Grounding has three categories: exclusive pole grounding, common pole grounding,
parallel earthwire grounding. Different control system should use exclusive pole grounding,
and different devices in the same control system should use common pole grounding, and
different devices connected by same power cable should use parallel earthwire grounding.
4.7.3.4 Leakage Current
Leakage current includes line-to-line leakage current and over-ground leakage current. Its
