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Chapter 6 EMC (Electromagnetic Compatibility)
6-1.Definition
Electromagnetic compatibility refers to the ability that the electric equipment runs in an
electromagnetic interference environment and implements its function stably without
interferences on the electromagnetic environment.
6-2.EMC standard
In accordance with the requirements of the Chinese national standard GB/T12668.3, the
inverter must comply with the requirements of electromagnetic interference and anti-
electromagnetic interference.
Our existing products adopt the latest international standards: IEC/EN61800-3: 2004
(AdjPstable sPeed electrical Power drive systems Part 3: EMC reqPirements and sPecific test
methods), which is equivalent to the Chinese national standards GB/T12668.3. EC/EN61800 -
3 assesses the inverter in terms of electromagnetic interference and anti-electronic
interference. Electromagnetic interference mainly tests the radiation interference, conduction
interference and harmonics interference on the inverter (necessary for civil inverter)
Anti-electromagnetic interference mainly tests the conduction immunity, radiation
immunity, surge immunity, EFTB(Electrical Fast Transi ent Burs) immunity, ESD immunity
and power low frequency end immunity (the specific test items includes:
of input voltage sag, interrupt and change; 2.commutation notch immunity; 3. harmonic input
immunity ; 4. input frequency change; 5. input voltage unbalance; 6. input voltage
fluctuation). The tests shall be conducted strictly in accordance with the above requirements
of IEC/EN61800-3, and our products are installed and used according to the guideline of the
Section 7.3 and can provide good electromagnetic compatibility in general industry
environment.
6-3.EMC directive
6-3-1.Harmonic effect
The higher harmonics of power supply may damage the inverter. Thus, at some places
where the quality of power system is relatively poor, it is recommended to install AC input
reactor.
6-3-2.Electromagnetic interference and installation precautions
There are two kinds of electromagnetic interferences, one is the interference from
electromagnetic noise in the surrounding environment to the inverter, and the other is t he
interference from the inverter to the surrounding equipments.
Installation Precautions:
1) The earth wires of the Inverter and other electric products ca shall be well grounded;
2) The power cables of the inverter power input and output and the cable of weak
current signal (e.g. control line) shall not be arranged in parallel but in vertical if possible.
3) It is recommended that the output power cables of the inverter shall use shield
cables or steel pipe shielded cables and that the shielding layer shall be grounded
reliably, the lead cables of the equipment suffering interferences shall use twisted-pair
shielded control cables, and the shielding layer shall be grounded reliably.
4) When the length of motor cable is longer than 30 meters, it needs to install
output filter or reactor.
61
1. Immunity tests
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