Chart 3-4:Ac300 Series Inverter System Grounding; Chart 3-5: Cable Earth Card For Cables Grounding - Veichi AC300 Series Technical Manual

AC300 Series Vector Control Inverter Manual
● The cutting terminal should be as soigne as possible. Unshielded wire section must be as short as possible.
● In control cable wiring, it should be as far from the power supply cable and motor cable as possible. And
independent cable trough should be used. While the control cable must cross to the power supply cable or motor cable,
it should be 90º vertical cross.
● Ensure that the contactor in the cabinet has wave surge suppresser. Or'R-C'damping circuit is connected to the
winding of AC contactor. Voltage dependent resistor corresponding to the winding voltage is used. And freewheel diode
or components such as voltage dependent resistor corresponding to the winding voltage are connected to DC contactor.
It is very important while contactor, controlled by output relay of inverter, acts frequently.
● Cable connected to motor should be shielded cable or armoured cable. The two barriers are earthed reliably by
cable grounding card.
● Build noise filters at the input side to reduce electromagnetic interference from other equipments at the power grid
side. The noise filter should be as close to the inverter power input terminal as possible. Meantime, the filter must earth
reliably as the inverter.
● Build noise filters at the output side to reduce radio interference and inductive disturbance. The noise filter must be
as close to the inverter output terminal as possible. Meantime, the filter must earth reliably as the inverter.
● Anytime, control circuit wire should be shielded cable.
● Add zero phase reactor in power supply wire near inverter input terminal and add zero phase reactor in the motor
wire near inverter output terminal to reduce electromagnetic interference to the inverter efficiently.
● Earthing Right and reliable earthing is the basic condition of safe and reliable running of the product. For right
earthing, please read the following notice carefully.
● In order to avoid electric shock, earthing cable should be the size as electric
equipment technique standard required and cable length should be as short as
possible. Otherwise, inverter leakage current will cause unstable potential of the
earthing terminal which is far from the earthing point, and electric shock accident will
happen frequently.
● Earth terminal must be earthing. Earth resistance must be below 10Ω.
Otherwise, there is danger of death.
● Please do not share earth cable with welder or other big current/pulse power
equipment. Otherwise, inverter will act abnormally.
● While multi inverters are used at the same time, please do not wind the earth
wire to loop-type. Otherwise, inverter will act abnormally.
Installation and Wiring
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AC300 Series Vector Control Inverter Manual

Chart 3-4:AC300 series inverter system grounding

Remark: motor must earth as close as possible. Motor case can not be connected to the inner earth terminal of the
inverter. It also can not share the earth net with the control system.
Shield of inverter power cable, motor cable and control cable
Shielding layer (reticulate/armoured) should be winded reliably by cable earth card and fix to inverter earth piece by
bolt. Please refer to the following chart.

Chart 3-5: Cable earth card for cables grounding

Corresponding relationship between inverter/motor cable length and carrier frequency
While cable distance between inverter and motor is long (especially low frequency output), cable voltage drop will
make motor torque reduce. Further more, cable HF leakage current will increase. Then inverter output current will
increase, that will cause inverter over-current trip. The current detection accuracy and running stability will be impacted.
Please follow as below table to adjust carrier frequency according to the cable length. While the cable distance is over
100m, please adopt distributed capacity reduce measure (Such as "no metal conductor covers cable", "wire each phase
cable apart" and so on).
Table 3-2: Corresponding relationship between inverter/motor cable length and carrier frequency
Cable length <20m
Carrier frequency 0.7~16kHz
Installation and Wiring
20~50m 50~100m >100m
0.7~8kHz 0.7~4kHz 0.7~2kHz
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