Appendix B Emc Installation Guidelines; Installation Guidelines Compliable With Emc Regulations - INVT Goodrive3000 Series Operation Manual

Goodrive3000 series medium voltage VFD EMC installation guidelines

Appendix B EMC installation guidelines

B.1 Installation guidelines compliable with EMC regulations
B.1.1 EMC general knowledge
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 equipment. 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 and capacitor are the transmission channels of interference.
Radiated interference is the interference transmitted in electromagnetic waves, 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 channels because the device as interference source or receiver cannot be changed.
Different electric and electronic devices, because of its various EMC standards or degrees, have different
EMC capacities.
B.1.2 EMC features
Like other electric or electronic devices, the VFD is not only an electromagnetic interference source but
also an electromagnetic receiver. The operating principle of the VFD determines that it can produce
certain electromagnetic interference noise. And the same time the VFD needs to be designed with certain
anti-jamming ability to ensure the smooth working in certain electromagnetic environment. The following
is its EMC features:
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.
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.
As the electromagnetic receiver, too strong interference will damage the VFD and influence the
normal using.
In the system, EMS and EMI of the VFD coexist. Decrease the EMI of the VFD can increase its EMS
ability.
B.1.3 EMC installation guidelines
In order to ensure all electric devices in the same VFD to work smoothly, this section, based on EMC
features of the VFD, introduces general EMC principles in several aspects including noise control, site
wiring and grounding for reference in site installation.
B.1.3.1 Noise control
All the connections to the control terminals must use shielded wire. And the shield layer of the wire must
ground near the wire entrance of the VFD. The ground mode is 360 degree annular connection formed by
cable clips. It is strictly prohibitive to connect the twisted shielding layer to the ground of the VFD, which
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