Mitsubishi Electric FR-A500 Instruction Manual page 44

2) Measures against noises which enter and cause misoperation of the inverter
When devices that generate many noises (which use magnetic contactors, magnetic brakes, many relays,
for example) are installed near the inverter and the inverter may be effected by noises, the following
measures must be taken:
•
Provide surge suppressors for devices that generate many noises to suppress noises.
•
Fit data line filters (refer to page 36) to signal cables.
•
Earth (Ground) the shields of the detector connection and control signal cables with cable clamp metal.
3) Techniques to reduce noises that are radiated by the inverter to malfunction peripheral devices.
Inverter-generated noises are largely classified into those radiated by the cables connected to the inverter
and inverter main circuit (I/O), those electromagnetically and electrostatically inducted 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 Air-propagated
noise noise
Magnetic induction
noise
Static induction
noise
Cable-propagated
noise
Noise 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.
(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) Inset line noise filters into I/O and radio noise filters into input side to suppress cable-radiated noises.
(5) Use shielded cables for 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.
4) 5) 6) (2) Run easily affected signal cables as far away as possible form the inverter.
(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 shielded cables for signal cables and power cables and run them in individual metal conduits to reduce
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 misoperate the devices
7) and the following measures must be taken:
(1) Install the radio noise filter (FR-BIF) to the power cables (input cables) of the inverter.
(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
8) 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.
Noise directly radi-
...
Path 1)
ated by inverter
Noise radiated by
...
Path 2)
power cables
Noise radiated by
...
Path 3)
motor cables
...
Path 4),5)
...
Path 6)
Noise propagated
...
through power
Path 7)
cables
Noise from earth
...
Path 8)
(ground) cable
due to leakage
current
35
INSTALLATION AND WIRING
5)
7)
2)
1)
3)
Instrument Receiver
Motor
Measures
Telephone
7)
Sensor
power supply
Inverter
8)
1)
6)
4)
Sensor
3)
IM
2