Siemens SINAMICS DCM Operating Instructions Manual page 92

Connecting
6.1 Instructions for EMC-compliant drive installation
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Footnotes
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Ground the shields of digital signal cables at both ends (source and destination),
ensuring 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)
outside the control cabinet.
Foil shields should be avoided as they are are at least 5 times less effective than
braided shields.
Shields for analog signal cables may be connected to ground at both ends if
equipotential 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
injections (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.
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.
RFI suppression filters must be used in order to conform to limit value class A1.
Additional loads must be connected upstream of the filter (on the line side).
The controller used and the manner in which the rest of the control cabinet is wired will
determine whether an additional line filter needs to be installed.
A line reactor must be included in the field circuit for controlled field power supplies.
A line reactor must be included in the armature circuit of the converter.
The motor cables do not have to be shielded. There must be a clearance of at least 20
cm between the power supply and the motor cables (field, armature). Use a partition if
necessary.
Signal cables are defined as:
Digital signal cables: e.g. cables for incremental encoders
Analog signal cables: e.g. ±10 V setpoint cable
Serial interfaces: e.g. PROFIBUS DP
Generally speaking, "ground" refers to all metallic conductive parts that can be
connected to a protective conductor, such as the cabinet enclosure, motor enclosure,
or foundation ground.
at several points, and connected at several points
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Operating Instructions, 1.2012, C98130-A7066-A1-05-7619
SINAMICS DCM DC Converter