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4.3.7 Operating instructions for power filter
A power filter shall be used for the device generating strong interference and sensitive to external interference. The
power line filter is a two-way low-pass filter, which allows DC or 50 Hz industrial frequency current to pass, and does not
allow the high-frequency electromagnetic interference current to pass.
Role of the power line filter
It can help the device meet the EMC requirements on conduction transmission and conduction sensitivity, and suppress
the radiation emission of the device.
It can prevent the electromagnetic interference of the device from entering the power line, and the interference of the
power line from entering the device.
Common errors for the power line filter installation
(1) Too long power input line
The filter shall be installed close to the power cable inlet of the cabinet, and the power input cable of the filter shall be
as short as possible in the cabinet.
(2) The input cable and output cable of the power line filter are too close to each other
If the input cable and output cable of the filter are too close to each other, the high-frequency interference signal will be
directly coupled through the input and output cables of the filter and bypass the filter, causing the power line filter
useless.
(3) Poor filter grounding
The filter enclosure must be reliably connected to the metal enclosure. There is usually a dedicated grounding terminal
on the filter enclosure. However, it is not effective for suppressing the high-frequency interference signal when you
choose to connect the filter to the metal enclosure with a cable, because the impedance of the long cable (not the
resistance of the resistor) is very large at high frequency, making the bypass less effective. The correct installation
method is to directly install the filter enclosure against the conducting surface of the equipment metal enclosure, with
the relevant insulating paint removed.
4.3.8 Drive radiation emission
The drive inevitably emits radiation during operation. The drive is installed in a metal cabinet in most cases, which
causes little radiation influence on equipment outside the cabinet. The external connecting cables are the main source
for radiation emission. Conduct proper wiring according to the requirements in this section, then the radiation emission
can be effectively suppressed.
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