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Electroma
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Shanghai Sigriner STEP Electric Co., Ltd.
A.6 Restraint of radiation from inverter
The control cabinet containing the inverter is generally made of metal, thus
reducing the radiation from the inverter to the instruments and equipment outside
the cabinet. The connecting cable is the major radiation source. Since the cables
for inverter power supply, motor, control circuit and keyboard shall be led out of the
shielded cabinet, special measures shall be taken at the cable entry, or the
shielding may be invalidated.
In Figure A.9, the cables in the shielded cabinet function as antenna receiving the
radiation inside the cabinet and sending it to the outer space. In Figure A.10, the
shield of the cable is connected to the cover at the exit and grounded, thus sending
the radiation in the cabinet directly to the ground and avoiding its going out.
In the shielded grounding shown in Figure A.10, the cable shield shall be grounded
as close to the exit as possible, or the length between the exit and the grounding
point still works as a coupling antenna. The distance between the grounding point
and the exit may not exceed 15cm and shall be as short as possible.
Figure A.9 Radiation from cables going out the shielded cabinet
Shielded cabinet
Cable
