Bosch Rexroth IPC, Connectivity Manual

Page: 41 / 99

Electrical Connections 5–3
1070 073 822-104 (02.06) GB
5.2 Interference suppression information
When designing the machine plant, observe and comply with governing regula-
tions 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 damage
on the machine plant caused by substandard EMC measures or line
transient interference!
Install signal voltage cables only at a sufficient distance from high-
voltage cables (e.g., motor power cables). If this is not possible, sep-
arate 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
Filters
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 these components should
be taken into consideration because they are most effective 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, electrical
symmetry or asymmetry must also be taken into consideration.
Besides symmetrical interference voltage components which occur
between mains connection cables, there are also asymmetrical interference
voltages caused, for example, by capacitive coupling of the source of
interference to the mains.
The following diagram shows a standard interference suppression circuit.
The asymmetrical interference voltages are discharged to the housing via
C
y
. C
x
damps the symmetrical interference.
C
y
L
L
Mains
C
y
C
x