The earth wires of the Inverter and other electric products shall be well grounded; 1)
The power input and output power cables of the inverter and weak current signal cables 2)
(e.g. control line) shall not be arranged in parallel and vertical arrangement is preferable.
It is recommended that the output power cables of the inverter employ shield cables or 3)
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.
When the length of motor cable is longer than 100 meters, it needs to install output îš¿lter or 4)
reactor.
7.3.3Handling method for the interferences of the surrounding equipment on the
inverter:
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:
For the measuring meters, receivers and sensors, their signals are generally weak. If they 1)
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 with the power cables in parallel 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 cycles; install EMC output îš¿lter in more severe
conditions.
When the equipment suffering interferences and the inverter use the same power supply, it 2)
may cause conduction interference. If the above methods cannot remove the interference,
it shall install EMC îš¿lter between the inverter and the power supply (refer to Section 7.3.6
for the prototyping operation); The surrounding equipment is separately earthed, which
can avoid the interference caused by the leakage current of the inverter’s earth wire when
common earth mode is adopted.
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:
Install surge suppressor on the devices generating interference;1)
Install filter at the input end of the inverter. Refer to Section 7.3.6 for the specific 2)
operations.
The lead cables of the control signal cable of the inverter and the detection line employ 3)
shielded cable and the shielding layer shall be earthed reliably.
7.3.4 Handling method for the interferences of inverter on the surrounding equipment:
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