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Chapter 3 Wiring of Inverter
19
3.6.4 Countermeasures for Conduction and Radiation Interference
Fig.3
−
4 Noise current illustration
When the input noise filter is installed, the wire connecting the filter to the inverter input power end shall
be as short as possible.
The filter enclosure and mounting cabinet shall be reliably connected in large area to reduce the back
flow impedance of the noise current Ig.
The wire connecting the inverter and the motor shall be as short as possible. The motor cable adopts
4
−
core cable, with the grounding end grounded at the inverter side, the other end connected to the
motor enclosure. The motor cable shall be sleeved into the metal tube.
The input power wire and output motor wire shall be kept away from each other as long as possible.
The equipment and signal cables vulnerable to influence shall be kept far away from the inverter.
Key signal cables shall adopt shielding cable. It is suggested that the shielding layer shall be grounded
with 360
−
degree grounding method and sleeved into the metal tube. The signal cable shall be kept far
away from the inverter input wire and output motor wire. If the signal cable must cross the input wire
and output motor wire, they shall be kept orthogonal.
When analog voltage and current signals are adopted for remote frequency setting, twinning shielding
cable shall be used. The shielding layer shall be connected to the grounding terminal PE of the inverter,
and the signal cable shall be no longer than 50m.
The wires of the control circuit terminals RA/RB/RC and other control circuit terminals shall be
separately routed.
It is forbidden to short circuit the shielding layer and other signal cables or equipment.
When the inverter is connected to the inductive load equipment (e.g. electromagnetic contactor, relay
and solenoid valve), surge suppressor must be installed on the load equipment coil, as shown in
Fig.3
−
5.
Fig.3
−
5 Application of inductive load surge suppressor
Input filter
Inverter
Filtering cable
Input filter
Inverter
Filtering cable
DC 24V
AC 220V
AC 220V
感性
负载
感性
负载
感性
负载
压敏
电阻
Inductive
load
Inductive
load
Inductive
load
P
iez
o
re
si
st
o
r
DC 24V
AC 220V
AC 220V
感性
负载
感性
负载
感性
负载
压敏
电阻
Inductive
load
Inductive
load
Inductive
load
P
iez
o
re
si
st
o
r