Mitsubishi Electric fr-e700 series, Instruction Manual

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Electromagnetic compatibility (EMC) Wiring
3 - 54
Noise
Propagation Path
Measures
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When devices that handle low-level signals and are liable to malfunction due to noises, e.g. instru-
ments, 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:
앫
Install easily affected devices as far away as possible from the inverter.
앫
Run easily affected signal cables as far away as possible from the inverter and its I/O cables.
앫
Do not run the signal cables and power cables (inverter I/O cables) in parallel with each other and
do not bundle them.
앫
Inserting a filter (dV/dt, sine wave filter) into the output suppresses the radiation noise from the
cables.
앫
Use shield cables as signal cables and power cables and run them in individual metal conduits to
produce further effects.
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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:
앫
Install easily affected devices as far away as possible from the inverter.
앫
Run easily affected signal cables as far away as possible from the I/O cables of the inverter.
앫
Do not run the signal cables and power cables (inverter I/O cables) in parallel with each other and
do not bundle them.
앫
Use shield cables as signal cables and power cables and run them in individual metal conduits to
produce further effects.
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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:
앫
Use additional (optional) noise filters as required.
앫
Install output filters to the power cables of the inverter after you consulted MITSUBISHI.
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When a closed loop circuit is formed by connecting the peripheral device wiring to the inverter, leak-
age 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.
Tab. 3-25: Noise and countermeasures
I001881E
Fig. 3-47: Noise reduction examples
Inverter
Enclosure
Inverter
power
supply
Sensor
M
3~
Motor
Control
power supply
Do not earth
enclosure directly
Do not earth shield
but connect it to signal common cable.
Use a twisted pair shielded cable
Use a shielded motor
power cable.
Install an output filter after you
consulted MITSUBISHI.
Decrease carrier
frequency.
Separate the inverter, power line,
and sensor circuit by more than 30 cm.
(at least 10 cm)
Power
supply for
sensor
Install an input filter after you
consulted MITSUBISHI.