Emc Regulations - INVT Goodrive800 Pro Series Hardware Manual

Goodrive800 Pro Series Basic Rectifier Unit Hardware Manual

4.3 EMC regulations

General knowledge of electromagnetic compatibility
EMC is short for electromagnetic compatibility, which refers to the ability of a device or system to function
properly in its electromagnetic environment and not constitute an unbearable electromagnetic disturbance
to anything in that environment. EMC includes two aspects: electromagnetic interference and
electromagnetic immunity.
Electromagnetic interference can be divided into two categories according to the transmission paths:
conducted interference and radiation interference.
Conducted interference propagates along any conductor. Therefore, any conductor, such as wire,
transmission line, inductor, and capacitor, is a transmission channel for conducted interference.
Radiated interference is in the form of electromagnetic waves that propagate with energy that is inversely
proportional to the square of the distance.
Electromagnetic interference must have three conditions or three elements at the same time: interference
source, transmission channel, and sensitive receiver, each of which is indispensable. The solution of EMC
problem mainly focuses the three elements. For users, the solution of EMC problem is mainly in
transmission channels because the equipment as interference source or receiver cannot be changed.
Different electric and electronic devices have different EMC capacities because of adopting different EMC
standards or classes.
General EMC guidelines on variable-frequency regulation system wiring
The following introduces general EMC guidelines on VFDs in several aspects including noise control, site
wiring and grounding for reference in site installation, with consideration of ECM characteristics of VFDs
where the input current and output voltage harmonics are relatively small but the voltage is high and the
current is large.
1. Noise control
All the connections to the VFD control terminals must use shielded wires. The shield layer of wire must be
grounded near the VFD entrance. The ground mode is 360-degree loop connection formed by cable clips. It
is not allowed to connect the twisted shield layer to the ground of the VFD, which greatly decreases or loses
the shield effect.
2. Site wiring
Power supply wiring: The shield layer of power supply incoming cables of the VFD shall be grounded reliably.
It is not allowed to route the power cables and control cables in parallel.
Device categorization: There are different electric devices in the same distribution system, which have
different ability of emitting and withstanding electromagnetic noise. Therefore, it needs to categorize these
devices into strong noise device and noise sensitive device. The same kind of devices needs to be placed in
the same area, and the distance between devices in different categories needs to be more than 20cm.
Wiring in the control cabinet: During wiring, signal cables and power cables need to be arranged in different
areas. It is not allowed to arrange them in parallel or in interlaced state at a close distance (less than 20cm)
or tie them together. If the signal cables have to cross the power cables, they need to be arranged in 90
degree angle.
3. Grounding
The VFD must be grounded safely and reliably in operation. Grounding has the priority in all EMC methods
because it does not only ensure the safety of equipment and persons, but also it is the simplest, most
effective and lowest-cost solution for EMC problems.
Three categories of grounding: special pole grounding, common pole grounding and series-wound
grounding. Different control system needs to use special pole grounding, different devices in the same
202202 (V1.0)
Electrical installation
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