Hitachi L100 IP Series Instruction Manual page 6

• Avoid parallel arrangement of „clean" and interference-prone conductors
3. Lay the motor cable and all analog and digital contol lines shielded.
• You should allow the effective shield area of these lines to remain as large as possible; i.e., do not
move the shield further away than absolutely necessary.
• With compact systems, if for example the frequency inverter is communicating with the steering unit,
in the same control cabinet connected at the same PE-potential, the screen of control lines should be
put on, on both sides with PE. With branch systems, if for example the communicating steering unit is
not in the same control cabinet and there is a distance between the systems, we recommend to put on
the screen of control lines only on the side of the frequency inverter. If it is possible, direct in the cable
entry section of the steering unit. The screen of motor cables always must be put on, on both sides with
PE.
• The large area contact between shield and PE-potential you can realise with a metal PG screw
connection or a metallic mounting clip.
• Use only copper mesh cable (CY) with 85% coverage
• The shielding should not be interrupted at any point in the cable. If the use of reactors, contactors,
terminals or safety switches in the motor output is necessary, the unshielded section should be kept as
small as possible.
• Some motors have a rubber gasket between terminal box and motor housing. Very often, the terminal
boxes, and particularly the threads for the metal PG screw connections, are painted. Make sure there is
always a good metallic connection between the shielding of the motor cable, the metal PG screw
connection, the terminal box and the motor housing, and carefully remove this paint if necessary.
4. Very frequently, interference is coupled in through installation cables. This influence you can minimize:
• Lay interfering cables separately, a minimum of 0.25 m from cables susceptible to interference.
• A particularly critical point is laying cables parallel over larger distances. If two cables intersect, the
interference is smallest if they intersect at an angle of 90°. Cables susceptible to interference should
therefore only intersect motor cables, intermediate circuit cables, or the wiring of a rheostat at right
angles and never be laid parallel to them over larger distances.
5. The distance between an interference source and an interference sink (interference-threatened device)
essentially determines the effects of the emitted interference on the interference sink.
• You should use only interference-free devices and maintain a minimum distance of 0.25 m from the
drive.
6. Safety measures
• Ensure that the protective conductor terminal (PE) of the filter is properly connected with the protective
conductor terminal of the frequency inverter. An HF ground connection via metal contact between the
housings of the filter and the frequency inverter, or solely via cable shield, is not permitted as
protective conductor connection. The filter must be solidly and permanently connected with the ground
potential so as to preclude the danger of electric shock upon touching the filter if a fault occurs. You
can achieve this by connecting it with a grounding conductor of at least 10 mm² or connecting a second
grounding conductor, connected with a separate grounding terminal, parallel to the protective
conductor (the cross section of each single protective conductor terminal must be designed for the
required nominal load).
Revision history table:
1
2
3
Revision contents Date of issue Manual no.