Mitsubishi Electric FR-A872-E Instruction Manual page 73

 Techniques to reduce electromagnetic noises that are radiated by the
inverter or the converter unit to cause the peripheral devices to
malfunction (EMI countermeasures)
Noises generated from the inverter or the converter unit are largely classified into those radiated by the cables connected to
the inverter or the converter unit and its main circuits (I/O), those electromagnetically and electrostatically induced to the signal
cables of the peripheral devices close to the main circuit power supply, and those transmitted through the power supply cables.
Inverter generated
electromagnetic
noise
Electromagnetic
propagated noise
Noise propagation
path
When devices that handle low-level signals and are liable to malfunction due to electromagnetic noises, e.g.
instruments, receivers and sensors, are contained in the enclosure that contains the inverter or the converter unit, or
when their signal cables are run near the inverter, the devices may malfunction due to by air-propagated
electromagnetic noises. The following countermeasures must be taken:
• Install easily affected devices as far away as possible from the inverter or the converter unit.
• Run easily affected signal cables as far away as possible from the inverter or the converter unit, and its I/O cables.
(a), (b), (c)
• Do not run the signal cables and power cables (inverter or converter unit I/O cables) in parallel with each other, and
• Set the EMC filter ON/OFF connector of the converter unit to the ON position. (Refer to
• Inserting a line noise filter into the output suppresses the radiated noise from the cables.
• Use shielded cables as signal cables and power cables and run them in individual metal conduits to produce further
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 cause malfunction of the devices and the following countermeasures must
be taken:
• Install easily affected devices as far away as possible from the inverter or the converter unit.
(d), (e), (f) • Run easily affected signal cables as far away as possible from the inverter or the converter unit, and its I/O cables.
• Do not run the signal cables and power cables (inverter or converter unit I/O cables) in parallel with each other, and
• Use shielded cables as signal cables and power cables and run them in individual metal conduits to produce further
When the power supplies of the peripheral devices are connected to the power supply of the inverter or the converter
unit in the same line, its generated noises may flow back through the power supply cables to cause malfunction of
(g) the devices and the following countermeasures must be taken:
• Set the EMC filter ON/OFF connector of the converter unit to the ON position. (Refer to
• Install the line noise filter to the power cables (output cables) of the inverter.
When a closed loop circuit is formed by connecting the peripheral device wiring to the inverter or the converter unit,
leakage currents may flow through the earthing (grounding) cable of the inverter or the converter unit to cause the
(h)
device to malfunction. In that case, disconnecting the earthing (grounding) cable from the device may stop the
malfunction of the device.
 Data line filter
Data line filter is effective as an EMI countermeasure. Provide a data line filter for the detector cable, etc.
• Commercially available data line filter: ZCAT3035-1330 (by TDK), ESD-SR-250 (by NEC TOKIN)
72
3. PRECAUTIONS FOR USE OF THE INVERTER
3.1 Electro-magnetic interference (EMI) and leakage currents
Noise directly radiated
Air propagated
from the inverter or the
noise
converter unit
Noise radiated from
power supply cable
Noise radiated from
motor connection cable
Path (d), (e)
induction noise
Electrostatic
Path (f)
induction noise
Electrical path Noise propagated through
power supply cable
Noise from earthing
(grounding) cable due to
leakage current
do not bundle them.
effects.
do not bundle them.
effects.
Path (a)
Path (b)
Path (c)
(g)
Instrument Receiver
Path (g)
Path (h)
Countermeasure
(e)
Telephone
(g)
(b)
(a)
Converter
power supply
unit
(c)
Inverter
(a)
(f)
(d)
(c)
Motor M
page 74.)
page 74.)
Sensor
(h)
Sensor