YASKAWA CIMR-ACA4011 Instruction Manual page 45

Preventing Inductive Noise
As described previously, a noise filter can be used to prevent inductive noise from being generated on the out-
put side. Alternatively, cables can be routed through a grounded metal pipe to prevent inductive noise. Keep-
ing the metal pipe at least 30 cm away from the signal line considerably reduces inductive noise.
Counteracting RMS
Radio noise is generated from the MxC as well as from the input and output lines. To reduce radio noise,
install noise filters on both input and output sides, and also install the MxC in a totally enclosed steel box.
The cable between the MxC and the motor should be as short as possible.
Cable Length between the MxC and Motor
If the cable between the MxC and the motor is comparatively long, the high-frequency leakage current will
increase, causing the MxC output current to increase as well. This may affect peripheral devices. To prevent
this, adjust the carrier frequency (set in C6-01, C6-02) as shown in Table 2.5 (for details, refer to Chapter 5
Parameters and Settings).
Cable length
Carrier frequency
-14
2
Power
supply
Fig 2.12 Countermeasures Against Inductive Noise
Power
MCCB
supply
Noise
filter
Fig 2.13 Countermeasures Against Radio Interference
Table 2.5 Cable Length between MxC and Motor
50 m max
12 kHz max
Metal pipe
MxC
IM
30 cm min.
Signal line
Controller
Steel box
Metal pipe
Noise
MxC
filter
100 m max
8 kHz max
IM
More than 100 m
4 kHz max