Chapter 4 Electrical Installation
Shenzhen Hpmont Technology Co., Ltd.
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HD3N-L Series User Manual V1.0
3.
Bad grounding of the EMI filter.
The enclosure of EMI filter must be grounded properly to the metal case of the controller. In order to achieve
better grounding effect, make use of a special grounding terminal on the enclosure. If using one cable to
connect the filter to the case, the grounding is useless for high frequency interference. When the frequency is
high, so is the impedance of cable, hence there is little bypass effect.
The correct installation: The filter should be mounted on the enclosure of equipment. Ensure to clear away the
insulation paint between the filter case and the enclosure for good grounding contact.
4.6.6
Countermeasures for Conduction, Radiation and Radio Frequency Interference
EMI of the Controller
The operating theory of controller means that some EMI is unavoidable.
The controller is usually installed in a metal cabinet which normally little affects the instruments
outside the metal cabinet. The cables are the main EMI source. If connect the cables according to this
manual, the EMI can be suppressed effectively.
If the controller and other control equipment are installed in one cabinet, the area rule must be
observed. Pay attention to the isolation between different areas, cable layout and shielding.
Reducing Conducted Interference
Add a noise filter to suppress conducted interference on the output side. Additionally, conducted
interference can be efficiently reduced by threading all the output cables through a grounded metal
tube.
And conducted interference can be dramatically decreased when the distance between the output
cables and the signal cables is above 0.3m.
Reducing RF Interference
The I/O cables and the controller produce radio frequency interference. A noise filter can be installed
both on the input side and output side, and shield them with iron utensil to reduce RF interference.
The wiring distance between the controller and the motor should be as short as possible shown in
Figure 4-9.
Figure 4-9 Reducing RF interference
X
X
X
M
～
Controller
EMI filter
EMI filter
Metal tube
Iron box
MCCB
