Omron SYSDRIVE 3G3MV User Manual page 52

Design
D Countermeasures against Induction Noise
As described previously, a Noise Filter can be used to prevent induction noise from
being generated on the output side. Alternatively, cables can be routed through a
grounded metal pipe to prevent induction noise. Keeping the metal pipe at least 30 cm
away from the signal line considerably reduces induction noise.
Power supply
D Countermeasures against Radio Interference
Radio noise is generated from the Inverter as well as the input and output lines. To
reduce radio noise, install Noise Filters on both input and output sides, and also install
the Inverter in a totally enclosed steel box.
The cable between the Inverter and the motor should be as short as possible.
Power supply
D Cable Length between Inverter and Motor
As the cable length between the Inverter and the motor is increased, the floating capa--
city between the Inverter outputs and the ground is increased proportionally. The in-
crease in floating capacity at the Inverter outputs causes the high-frequency leakage
current to increase, and this may adversely affect peripheral devices and the current
detector in the Inverter's output section. To prevent this from occurring, use a cable of no
more than 100 meters between the Inverter and the motor. If the cable must be longer
than 100 meters, take measures to reduce the floating capacity by not wiring in metallic
ducts, by using a separate cable for each phase, and so on.
Also adjust the carrier frequency (set in n80) according to the cable length between the
Inverter and the motor, as shown in the table below.
Metal pipe
3G3MV
SYSDRIVE
Signal line
Steel box
3G3MV
Noise
SYSDRIVE
Filter
30 cm min.
Controller
Metal pipe
Noise
Filter
Chapter 2
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