Siemens SIRIUS 3RT - Configuration

Accessories
9.4 Surge suppressor
SIRIUS - SIRIUS 3RT Contactors/Contactor assemblies
300 Manual, 09/2017, A5E03656507120A/RS-AE/006
9.4.2
Configuration
Selection aid
The table below compares the effects of the different surge suppressors and specifies the
applications to which they are most suited.
Table 9- 19 Mode of operation and preferred applications of surge suppressors
Surge suppressor
Suitable
for
Control
voltage
Overvoltage
is limited ...
Effect
Advantages/disadvantages
Preferred
application
Noise
suppression
/freewheel
diode
DC To 0.7 V
• OFF-delay
becomes
considerably
longer (6 to
10 times)
• With
contactors of
size S0 or
larger,
"2-stage
drop-out"
1)
cannot be
excluded
Advantages
• Simple
implementation
• Reliable
• Non-critical
dimensioning
• Low induction
voltage
Instable control
commands/con
trol supply
voltage
Disadvantages
• Long drop-out
delay
• Only suitable for
size S00
Diode
combination
: Noise
suppression
and Zener
diode
DC To Zener
voltage
• OFF-delay
becomes
longer (2 to 6
times)
• A 2-stage
drop-out no
longer occurs
Advantages
• Non-critical
dimensioning
EMC-critical
components in
the vicinity
Disadvantages
• Attenuation only
above U
ZD
(10 V)
Varistor AC/DC To varistor
voltage
• OFF-delay
becomes only
slightly longer
(2 to 5 ms)
Advantages
• Energy
absorption
• Non-critical
dimensioning
• Simple
implementation
Suitable for
most standard
applications,
e.g. in the
SIMATIC
environment
Disadvantages
• Attenuation only
above U
VDR