Siemens SIRIUS M200D Manual page 184

Technical data
8.8 Electrical service life of contactor
If mixed operation is available, i.e. if normal switching operation (breaking of rated operating
current in accordance with utilization category AC-3) is mixed with occasional inching
(breaking of the multiple rated operating current in accordance with utilzation category AC-
4), the service life of the contacts can be calculated approximately with the following formula:
X
A
B
C
P
N
I
a
I
e
Figure 8-2
184
Contact service life for mixed operation in operating cycles
Contact service life for normal operation (I
Contact service life for inching (I
Proportion of inching operations in the total operations as a percentage
Rated power of three-phase motors at 400 V
Breaking current
Rated operating current
Service life of main contacts for contactor 3RT1017
= I ) in operating cycles
a e
= multiple of I ) in operating cycles
a e
Manual, 08/2014, A5E01577426A/RS-AA/004
M200D PROFIBUS/PROFINET