Chapter 7 EMC (Electromagnetic Compatibility)
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1ǃ The earth wires of the Inverter and
other electric products shall be well
grounded;
2ǃ The power input and output power
cables of the inverter and weak current
signal cables (e.g. control line) shall
not be arranged in parallel and vertical
arrangement is preferable.
3ǃ It is recommended that the output
power cables of the inverter employ
shield cables or steel pipe shielded
cables and that the shielding layer be
earthed reliably. The lead cables of the
equipment suffering interferences are
recommended to employ twisted-pair
shielded control cables, and the
shielding layer shall be earthed reliably.
4ǃ When the length of motor cable is
longer than 100 meters, it needs to
install output filter or reactor.
7.3.3Handling method for the
interferences of the surrounding
magnetic equipment on the inverter:
The electromagnetic interference on
the inverter is generated because plenty of
relays, contactors and electromagnetic
brakes are installed near the inverter.
When the inverter has error action due to the
interferences, the following measures can be
taken:
ǃ Install surge suppressor on the
devices generating interference;
ǃ Install filter at the input end of the
inverter. Refer to Section 7.3.6 for
the specific operations.
ǃ The lead cables of the control signal
cable of the inverter and the
detection line employ shielded cable
and the shielding layer shall be
earthed reliably.
7.3.4 Handling method for the
interferences of inverter on the
surrounding magnetic equipment:
These interferences include two types:
one is radiation interference of the inverter,
and the other is conduction interference of
the inverter. These two types of
interferences cause the surrounding electric
equipment to suffer electromagnetic or
electrostatic induction. The surrounding
equipment hereby produces error action.
For different interferences, it can be handled
by referring to the following methods:
1ǃ For the measuring meters, receivers
and sensors, their signals are
generally weak. If they are placed
nearby the inverter or together with
the inverter in the same control
cabinet, they are easy to suffer
interference and thus generate error
actions. It is recommended to handle
with the following methods: Put in
places far away from the interference
source; do not arrange the signal
cables in parallel with the power
cables and never bind them together;
both the signal cables and power
cables employ shielded cables and
are well earthed; install ferrite
magnetic ring (with suppressing
frequency of 30 to 1,000MHz) at the
output side of the inverter and wind it
2 to 3 turns; install EMC output filter if
the situation is terrible.
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