User's Manual

Technical specifications
8.8 Electrical service life of contactor
M200D AS-Interface Basic
96 Manual, 03/2009, A5E01668085-01
8.8 Electrical service life of contactor
Service life of main contacts (DSte / RSte) to 5.5 kW
The curves show the contact service life of contactors when switching ohmic and inductive
three-phase loads (AC-1/AC-3) as a function of breaking current and rated operating voltage.
The prerequisite for this are command devices that switch at random, i.e. not synchronously
to the phase angle of the line.
The rated operating current I
e
in accordance with utilization category AC-4 (breaking of 6
times the rated operating current) is determined for a contact service life of at least 200 000
operating cycles.
If a smaller contact service life is sufficient, the rated operating current I
e
/AC-4 can be
increased.
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
1+C/100(A/B-1)
X Contact service life for mixed operation in operating cycles
A Contact service life for normal operation (I
a
= I
e
) in operating cycles
B Contact service life for inching (I
a
= multiple of I
e
) in operating cycles
C Proportion of inching operations in the total operations as a percentage