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3.2
Cabinet design
In addition to the EMC countermeasures described in this chapter, NFPA79 approved by the United States
requires that the wiring between a servo amplifier and a servo motor be insulated from wiring of other control
or signal circuits if a shielded wire is not used. (Example: 100 mm or more for 20 A or less)
The servo is a complex component incorporated into another machine. The servo amplifier must be installed in a cabinet.
The design and layout of the cabinet is a very important factor in EMC countermeasures. Consider the following when
designing the cabinet.
Precautions for cabinet design
1.
Use a metal cabinet.
2.
Securely ground the cabinet using as thick and short wire as possible.
3.
Weld or screw the top and side plates of the cabinet together so that there are no gaps. The distance between the joints
should be 10 cm or less. The diameter of the openings on the cabinet such as the ventilation hole should be 10 cm or
less. If there are holes larger than this, plug them with metal plates or punched metal. In such a case, make sure that
there are no metal or conductor with insufficient electrical connections, such as connection between painted surfaces.
Hole exceeding 10 cm
3 EMC COUNTERMEASURES
8
3.2 Cabinet design
Remove paint
* Provide an electrical continuity.
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