User manual of EC160 elevator intelligent integrated machine Installation and wiring
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4.6 Installation guideline to EMC compliance
4.6.1 General knowledge of EMC
EMC is the abbreviation of electromagnetic compatibility, which means the device or system has the
ability to work normally in the electromagnetic environment and will not generate any electromagnetic
interference to other equipments. EMC includes two subjects: electromagnetic interference and
electromagnetic anti-jamming.
According to the transmission mode, electromagnetic interference can be divided into two 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
inversely 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.
Because different electric and electronic devices vary in EMC standards or degrees, the EMC ability
is also different.
4.6.2 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:
z 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.
z Output voltage is high frequency PWM 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.
z As the electromagnetic receiver, too strong interference will damage the inverter and influence
the normal using of customers.
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