Emc Directives - Siemens G120P Manual

2.7
Siemens AG

EMC directives

1. Connections and interference suppression
- Create the connections as permanent connections.
- Use special washers which penetrate the insulation surface for screw
connections on painted or anodized metal components. This serves to
create a metallically conducting contact. Or remove the insulation surface
at the contact points.
- Contactor coils, relays, solenoid valves, and motor holding brakes must
feature interference suppressors which reduce high frequency interference
when the contacts are opened. Interference suppressors are RC elements
or varistors for AC-operated coils and freewheel diodes for DC-operated
coils. Connect the interference suppressors directly to the corresponding
coil.
2. Cabling
- Keep the wiring as short as possible.
- Lay signal and data cables as well as the equipotential bonding cables
parallel and as close to one another as possible.
- Ground replacement wires for signal and data cables at either end in the
sense of additional shielding.
- Lay line and motor cables separate from the signal and data cables.
Maintain a minimum clearance of approximately 25 cm.
- Shield the power cable between the drive and the motor. Use three-core,
symmetrical three-phase cable. Shielded cables with three symmetrical
phase conductors (L1, L2 and L3) as well as an integrated, three-core and
symmetrically arranged PE conductor are ideally suited for this.
- Lay the shielded power cable to the motor separately from the two motor
temperature sensor cables (PTC/KTY) because they are treated like signal
cables.
- Shield signal and data cables in order to avoid inductive or capacitive
interference or stray radiation.
- Lay particularly sensitive signal cables, such as setpoint or actual value
cables, in such a way that optimized and interruption-free shield bonding
exists at either end.
- Where possible, lay cable shields immediately after the point where the
cable enters the control cabinet or, in the case of IP55 type of equipment,
at the designated points.
- Use EMC shield bars for power cables and use the shield support elements
provided in the drive for signal and data cables (shield connection kit for the
Control Unit).
3. Cable shields
- Use shielded cables with finely stranded braided shields. Foil shields are
not suitable because they are considerably less effective.
- Lay the shields over as large a surface as possible at either end, with
optimized electrical conductivity to the grounded enclosure. This is the only
way of reducing inductive or capacitive interference or stray radiation to a
minimum.
Mounting and installation
EMC directives
CM2G5111en
2014-05-16
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