Mitsubishi Electric FR-A740-00023 Instruction Manual page 63

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.
(2) Run easily affected signal cables as far away as possible from the inverter and its I/O cables.
1) 2) 3)
(3) Do not run the signal cables and power cables (inverter I/O cables) in parallel with each other and do
(4) Set the EMC filter ON/OFF connector of the inverter to the ON position. (Refer to page 13)
(5) Inserting a line noise filter into the output suppresses the radiation noise from the cables.
(6) Use shield cables as signal cables and power cables and run them in individual metal conduits to
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 do
(4) Use shield cables as signal cables and power cables and run them in individual metal conduits to
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 malfunction
7) the devices and the following measures must be taken:
(1) Set the EMC filter ON/OFF connector of the inverter to the ON position. (Refer to page 13)
(2) Install the line noise filter (FR-BLF, FR-BSF01) 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 earth (ground) cable of the inverter to malfunction the device. In such a
case, disconnection of the earth (ground) cable of the device may cause the device to operate properly.
Data line filter
Noise entry can be prevented by providing a data line filter for the detector cable etc.
Noise reduction examples
Inverter
power
supply
Separate the inverter and
power line by more than
30cm (at least 10cm) from
sensor circuit.
Control
power
supply
Do not earth (ground)
enclosure directly
not bundle them.
produce further effects.
not bundle them.
produce further effects.
Decrease carrier
frequency
Enclosure
EMC filter Inverter
Power
supply
for sensor
Do not earth (ground)
control cable
Noise and leakage currents
Measures
Install the filter (FR-BLF, FR-BSF01)
on the inverter output side
FR-
BLF IM
Use 4-core cable for motor power cable
and use one cable as earth (ground) cable.
Use a twisted pair shielded cable
Sensor
Do not earth (ground) shield
but connect it to signal common cable.
Motor
3
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