Mitsubishi Electric FR-V560 Instruction Manual page 33

Others
Noise Propagation
Path
When devices that handle low-level signals and are liable to malfunction due to noises, e.g.
instruments, receivers and sensors, are contained in the enclosure that contains the inverter or when
their signal cables are run near the inverter, the devices may be malfunctioned by air-propagated
noises. The following measures must be taken:
(1) Install easily affected devices as far away as possible from the inverter.
1), 2), 3) (2) Run easily affected signal cables as far away as possible from the inverter and its I/O cables.
(3) Do not run the signal cables and power cables (inverter I/O cables) in parallel with each other and
(4) Insert line noise filters into I/O and radio noise filters into input to suppress cable-radiated noises.
(5) Use shielded cables as signal cables and power cables and run them in individual metal conduits
When the signal cables are run in parallel with or bundled with the power cables, magnetic and static
induction noises may be propagated to the signal cables to malfunction the devices and the following
measures must be taken:
(1) Install easily affected devices as far away as possible from the inverter.
4), 5), 6) (2) Run easily affected signal cables as far away as possible from the I/O cables of the inverter.
(3) Do not run the signal cables and power cables (inverter I/O cables) in parallel with each other and
(4) Use shielded cables as signal cables and power cables and run them in individual metal conduits
When the power supplies of the peripheral devices are connected to the power supply of the inverter in
the same line, inverter-generated noises may flow back through the power supply cables to
7) malfunction the devices and the following measures must be taken:
(1) Install the radio noise filter to the power cables (input cables) of the inverter.
(2) Install the line noise filter to the power cables (I/O cables) of the inverter.
When a closed loop circuit is formed by connecting the peripheral device wiring to the inverter, leakage
8) currents may flow through the ground cable of the inverter to malfunction the device. In such a case,
disconnection of the ground cable of the device may cause the device to operate properly.
Data line filters
Noise entry can be prevented by providing a data line filter for the detector cable etc.
Example of noise reduction techniques
Install line noise filter
on inverter input side.
Inverter
power supply
Separate inverter and power line
by more than 30cm (11.8inches)
(at least 10cm (3.93inches)) from
sensor circuit.
Control
power supply
do not bundle them.
to produce further effects.
do not bundle them.
to produce further effects.
Control box
line
noise
filter
Install radio noise filter
on inverter input side.
radio
noise
filter
Power supply
for sensor
Do not ground
control box directly.
Do not ground
control cable.
Measures
Reduce carrier
Install line noise filter
frequency.
on inverter output side.
line
noise
Inverter
filter
Use 4-core cable as motor
power cable and use one wire
as ground wire.
Use twisted pair shield cable.
Sensor
Do not ground shield but connect
it to common cable of signal.
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IM
Motor