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Main circuit terminals
1.2.8
Regarding noise and the installation of a noise filter
Some noise enters the inverter causing it to malfunction and others are generated by
the inverter causing the malfunction of peripheral devices. Though the inverter is
designed to be insusceptible to noise, 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 the inverter, motor, etc. at one point.
Capacitances exist between the inverter's I/O wiring, other cables, earth and motor,
through which leakage currents flow to cause the earth leakage circuit breaker,
earth 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 leakage circuit breaker designed for suppression of harmonics
and surges, and use the electronic thermal relay function 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, install a FR-BIF(-H) optional radio noise filter (for use on the
input side only) or FR-BSF01 line noise filter to minimize interference.
<Noise reduction examples>
Install filter
FR-BSF01
on inverter's input side.
Inverter
power supply
Install filter FR-BIF
on inverter's input side.
Separate inverter and power
line by more than 30cm and
at least 10cm from sensor
circuit.
Control
power supply
Do not earth control
box directly.
Control
Reduce carrier
box
frequency.
FR-
Inverter
BSF01
FR-BIF
Power
supply
for sensor
Do not earth
control cable.
16
Install filter
on inverter's output side.
FR-
BSF01
Use 4-core cable for motor
power cable and use one
cable as earth cable.
Use twisted pair shielded cable.
Sensor
Do not earth shield but connect
it to signal common cable.
FR-BSF01
IM
Motor
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