Siemens SINAMICS DCM Manual page 98

Rules for EMC-compliant installation
1 Connect all metallic parts of the control cabinet to one another over a flat area with
good conductivity (not paint against paint!). Use contact or scratch washers if neces-
sary. The cabinet door must be connected to the cabinet using the shortest possible
ground strips (at the top, center, and bottom).
2 Contactors, relays, solenoid valves, electromechanical operating hours counters, etc.,
in the cabinet and - where applicable - in neighboring cabinets - must be provided with
quenching combinations such as RC elements, varistors, and diodes. These must be
connected directly at the appropriate coil.
3 Whenever possible, guide signal cables
4 Unshielded cables in the same circuit (outgoing/incoming conductors) must be twisted
where possible, or the area between them minimized, to prevent unnecessary frame
antennae.
5 Connect spare wires to the cabinet ground
shielding effect.
6 Avoid unnecessary cable lengths in order to keep coupling capacities and inductances
low.
7 Crosstalk is generally reduced if the cables are laid close to the control cabinet ground.
Do not, therefore, route cables freely around the cabinet, but lay them as close as pos-
sible to the cabinet enclosure/mounting plates. This also applies to spare cables.
8 Signal and power cables must be physically separated (to prevent coupling paths).
Minimum clearance: You should aim for a minimum of 20 cm.
If it is not possible to physically separate the encoder and motor cables, the encoder
cable must be decoupled either using a partition or by laying it in a metal conduit. The
partition or metal conduit must be grounded at several points.
9 Ground the shields of digital signal cables at both ends (source and destination), ensur-
ing maximum contact area and good conductivity. In the event of poor equipotential
bonding between the shield connections, run an additional equalizing conductor with a
cross-section of at least 10 mm² parallel to the shield for the purpose of reducing the
shield current. Generally speaking, the shields may also be connected to the cabinet
enclosure (ground)
control cabinet.
Foil shields should be avoided as they are are at least 5 times less effective than braid-
ed shields.
10 Shields for analog signal cables may be connected to ground at both ends if equipoten-
tial bonding is good (this must be done over a large area with good conductivity). It can
be assumed that equipotential bonding is good if all metal parts are well interconnected
and the electronics components are supplied from a single source.
Connecting shields at one end prevents low-frequency, capacitive interference injec-
tions (e.g. 50 Hz humming). In this case, the shield should be connected in the control
cabinet; a sheath wire may also be used for this purpose.
The cable to the temperature sensor on the motor (X177:53 to 55) must be shielded
and connected to ground at both ends.
11 Ensure that the RFI suppression filter is always located close to the suspected source
of interference. The filter must be attached to the cabinet enclosure, mounting plate,
etc., over a flat area. Incoming and outgoing cables must be physically separated.
SINAMICS DCM DC Converter
Operating Instructions, 02.2015, A5E34763375/RS-AA/001
6.1 Instructions for EMC-compliant drive installation
into the cabinet at one level only.
1)
2)
at several points, and connected at several points outside the
2)
ac.maher.co.ir
at both ends. This achieves an additional
Connecting
99