Siemens SIRIUS 3RT Series System Manual page 120

SIRIUS 3RT2 contactors/contactor assemblies
2.4 Configuration
Using the S00 and S0 contactors at lower ambient temperatures
The S00 and S0 contactors can be used at a minimum ambient temperature of Tu = -50 °C,
but the mechanical durability will be reduced by up to 50%. The other catalog data remains
unaffected. However, measures will need to be taken to combat condensation (e.g. control
cabinet heating). In such instances a high switching frequency and long duty cycle are
preferable to a low switching frequency and short duty cycle. Contactors which contain
electronics or which are combined with electronic accessories must not be used at
temperatures below Tu = -40 °C.
Service life
Using the contactors at higher ambient temperatures places a greater stress on molded
parts, main current paths, and the mechanism. This reduces the mechanical durability and
shortens the service life of the contactors. The service life is primarily influenced by the ON
period. The table below shows the reduced mechanical durability and shortened service life
values:
Table 2- 9
Ambient temperature Tu
≤ 60 °C
65 °C
70 °C
The specifications for the service life apply to an ON period of 100%. At an ON period
of 50%, the values double.
Reference
More information ...
About the environments in which power
contactors are used
120
Durability and service life of 3RT20 contactors
S00
Mechanical durability [x10
cycles]
30
15
3
S0 S00 and S0
operating Service life [years]
6
10 20
5 15
1 10
Can be found in the chapter titled ...
Contactors for switching motors (3RT20)
(Page 228)
System Manual, 01/2011, A8E56203870002-03
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