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1070072365 / 04
RhoMotion
Electrical Connections
4.2
Interference suppression information
When designing the machine plant, observe and comply with governing
regulations and statutory law with regard to interference suppression on
individual components. This will increase the operational safety of the
entire system.
DANGER
Dangerous conditions, functional failures and equipment da-
mage on the machine plant caused by substandard EMC mea-
sures or line transient interference!
Install signal voltage cables at a sufficient distance from high-
voltage cables (e.g., motor power cables). If this is not possi-
ble, separate metallic cable channels must be used.
The following sections are designed to provide you with a brief overview
of possible interference suppression measures in the control cabinet.
Among these are, for example:
D Filter
D Spark quenching circuits
D Damping of inductive switching peaks
D Limitation of switching voltage of high-speed semiconductors
D Screening
To ensure optimum suppress interference, all of the above compo-
nents should be taken into consideration because they are most ef-
fective when working in combination. In principle, interference
suppression should be implemented as follows:
D Apply suppression measures as close to the source of interference as
possible
D Use only components that are identified as interference suppressors
D Limit leakage currents in accordance with safety regulations
D Provide touch guards
D Prevent vibration fatigue breakage by providing secure mechanical
support for interference suppressors.
To ensure that interference suppression measures are successful, elec-
trical symmetry or asymmetry must also be taken into consideration.
Besides symmetrical components of interference voltage that occur bet-
ween the mains connection cables, asymmetrical interference voltages
occur as well. They are caused by capacitive coupling of the interference
source with the mains network.
The following diagram shows a standard interference suppression cir-
cuit. Here, the asymmetrical interference voltages are discharged to the
housing via C
. By contrast, C
y
Electric Drives
Bosch Rexroth AG
and Controls
dampens the symmetrical interference.
x
4−3
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