Mitsubishi Electric F700 Instruction Manual page 40

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 not bundle them.
(4) Use the inverter with the ON/OFF connector of the EMC filter set to ON. (Refer to page 34)
(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
produce further effects.
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.
(2) Run easily affected signal cables as far away as possible from the I/O cables of the inverter.
4) 5) 6)
(3) Do not run the signal cables and power cables (inverter I/O cables) in parallel with each other and
do not bundle them.
(4) Use shield cables as signal cables and power cables and run them in individual metal conduits to
produce further effects.
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 the devices and the following measures must be taken:
7)
(1) Use the inverter with the ON/OFF connector of the EMC filter set to ON. (Refer to page 34)
(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
currents may flow through the earth cable of the inverter to malfunction the device. In such a case,
8)
disconnection of the earth cable of the device may cause the device to operate properly.
Noise reduction examples
Inverter
power
supply
Separate the inverter,
power line, and sensor
circuit by more than 30cm.
(at least 10cm)
Control
power
supply
Do not earth
enclosure directly
Do not earth control cable
Decrease carrier
Enclosure frequency
FR-
EMC filter Inverter BLF
Use a twisted pair shielded cable
Power
supply
for sensor
Do not earth shield
but connect it to signal common cable.
Measures
Install the filter (FR-BLF, FR-BSF01)
on the inverter output side
IM Motor
Use 4-core cable for motor power cable
and use one cable as earth cable.
Sensor
Others
2
33