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Peripheral Devices
1.10.5 Regarding noises and the installation of the noise filter
Some noises enter the inverter causing it to malfunction and others are generated by
the inverter causing peripheral devices to malfunction. Though the inverter is designed
to be insusceptible to noises, it handles low-level signals, so it requires the following
general countermeasures to be taken.
(1) General countermeasures
•
Do not run the power cables (I/O cables) and signal cables of the inverter in parallel
with each other and do not bundle them.
•
Use twisted shield cables for the detector connecting and control signal cables and
connect the sheathes of the shield cables to terminal SD.
• Earth (Ground) the inverter, motor, etc. at one point.
• Capacitances exist between the inverter's I/O wiring, other cables, earth (ground)
and motor, through which leakage currents flow to cause the earth (ground) leakage
circuit breaker, earth (ground) leakage relay and external thermal relay to operate
unnecessarily. To prevent this, take appropriate measures, e.g. set the carrier
frequency in Pr. 72 to a low value, use an earth (ground) leakage circuit breaker
designed for suppression of harmonics and surges, and use the electronic
overcurrent protection built in the inverter.
• The input and output of the inverter main circuit include high-degree harmonics,
which may disturb communication devices (AM radios) and sensors used near the
inverter. In this case, disturbance can be reduced by mounting the FR-BIF radio
noise filter (for input side only) or FR-BSF01 line noise filter.
Noise reduction technique examples
FR-
BSF01
FR-
BIF
IM
FR-
BSF01
Install filter (FR-BSF01)
on inverter's input side.
nverter
ower supply
Install filter FR-BLF on
inverter's input side.
Separate inverter and power
line more than 30cm (at least
10cm) from sensor circuit.
C
ontrol
p
ower supply
Do not earth (ground)
control box directly.
Do not earth (ground) control cable.
Control box
Reduce carrier frequency.
Inverter
Power
supply
for sensor
Install filter (FR-BSF01)
on inverter's output side.
Motor
Use 4-core cable for motor
power cable and use one
cable as earth (ground) cable.
Use twisted pair shielded cable.
Sensor
Do not earth (ground) shield but connect
it to signal common cable.