SIRIUS 3RT2 contactors/contactor assemblies   
2.4 Configuration 
  SIRIUS Innovations 
120  System Manual, 01/2011, A8E56203870002-03 
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  Durability and service life of 3RT20 contactors 
  S00  S0  S00 and S0 
Ambient temperature Tu  Mechanical durability [x10
6
 operating 
cycles] 
Service life [years] 
≤ 60 °C  30  10  20 
65 °C  15  5  15 
70 °C  3  1  10 
 
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 ...  Can be found in the chapter titled ... 
About the environments in which power 
contactors are used 
Contactors for switching motors (3RT20) 
(Page 228)