Wiring
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categories: conducted interference and radiated interference.
Conducted interference is the interference transmitted by conductor. Therefore, any
conductors (such as wire, transmission line, inductor, capacitor and so on) are the
transmission channels of the interference.
Radiated interference is the interference transmitted in electromagnetic wave, and the
energy is inverse proportional to the square of distance.
Three necessary conditions or essentials of electromagnetic interference are:
interference source, transmission channel and sensitive receiver. For customers, the
solution of EMC problem is mainly in transmission channel because of the device
attribute of disturbance source and receiver can not be changed
4.7.2 EMC features of inverter
Like other electric or electronic devices, inverter is not only an electromagnetic
interference source but also an electromagnetic receiver. The operating principle of
inverter determines that it can produce certain electromagnetic interference noise. And
the same time inverter should be designed with certain anti-jamming ability to ensure the
smooth working in certain electromagnetic environment. The following is its EMC
features:
4.7.2.1 Input current is non-sine wave. The input current includes large amount of
high-harmonic waves that can cause electromagnetic interference, decrease
the grid power factor and increase the line loss.
4.7.2.2 Output voltage is high frequency PMW wave, which can increase the
temperature rise and shorten the life of motor. And the leakage current will also
increase, which can lead to the leakage protection device malfunction and
generate strong electromagnetic interference to influence the reliability of other
electric devices.
4.7.2.3 As the electromagnetic receiver, too strong interference will damage the
inverter and influence the normal using of customers.
4.7.2.4 In the system, EMS and EMI of inverter coexist. Decrease the EMI of inverter
can increase its EMS ability.
4.7.3 EMC Installation Guideline
In order to ensure all electric devices in the same system to work smoothly, this section,
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