Mitsubishi Electric FR-A700 Instruction Manual page 101

Wiring
Noise
Propagation Path
Tab. 3-28: Noise and Countermeasures
Fig. 3-49: Noise reduction examples
FR-A700 EC
Measures
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:
Install easily affected devices as far away as possible from the inverter.
Run easily affected signal cables as far away as possible from the inverter and its I/O
cables.
Do not run the signal cables and power cables (inverter I/O cables) in parallel with each
other and do not bundle them.
Use the inverter with the ON/OFF connector of the EMC filter set to ON.
(Refer to section 3.9.3.)
Inserting a filter (dU/dt, sine wave filter) into the output suppresses the radiation noise from
the cables.
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:
Install easily affected devices as far away as possible from the inverter.
Run easily affected signal cables as far away as possible from the I/O cables of the inverter.
Do not run the signal cables and power cables (inverter I/O cables) in parallel with each
other and do not bundle them.
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:
Use the inverter with the ON/OFF connector of the EMC filter set to ON.
(Refer to section 3.9.3.)
Use additional (optional) noise filters as required.
Install output filters to the power cables of the inverter after you consulted MITSUBISHI.
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, disconnection of the earth cable of the device may cause the device to operate
properly.
Enclosure
Inverter
power
supply
Separate the inverter, power line,
and sensor circuit by more than 30cm.
(at least 10cm)
Control
power supply
Electromagnetic compatibility (EMC)
Decrease carrier
frequency.
EMC filter Inverter
Use a twisted pair shielded cable
Power
supply for
sensor
Do not earth shield
but connect it to signal common cable.
Install an output filter after you
consulted MITSUBISHI.
M
Motor
3~
Use a shielded motor
power cable.
Sensor
I001050E
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