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2019-08-07 / V1.0
Maintenance
Contactors C193/C294 – Installation and Maintenance Instructions
8. Maintenance
Note the expert knowledge which is essential for car-
rying out maintenance work, mentioned in chapter
“2. General and security information”.
8.1 Safety
DANGER
The contactors are used to switch voltage. The touching of electrically conducting parts may result
in serious injuries or even death!
Energized parts are all metal parts belonging directly to one of the circuits or wires leading there. All
other visible metal parts and wires may also be energized in the case of a failure.
Before beginning any work on the contactors, always observe the following safety regulations:
X
Disconnect on all sides
X
Ensure that it is not possible to reconnect unintentionally
X
Clearly mark your work area
X
Make sure that there is no voltage present
X
Earth and short circuit the installation; this also includes the discharging of any capacitors in
the main circuit
X
Besides the main electric circuit, also disconnect additional and auxiliary circuits
X
Cover or insulate adjacent energized parts
X
Only an electrically skilled person may determine if there is no voltage present
X
When the work has been concluded, proceed the other way round.
8.2 Preventive maintenance
Contactors of the C193 and C294 series are mainte-
nance-free within the rated mechanical life time. The
electrical life time depends on the number of switch-
ings under heavy load conditions and may vary for dif-
ferent applications. In normal use, this corresponds to a
decade-long operating period.
Intervals for regular checks
To ensure the correct function and a prolonged opera-
tional life span of the contactors, the following checks
and maintenance must be performed regularly.
Checks
Interval
Visual inspection of the contactor
from outside
X
1x per year
Inspection of the auxiliary switch
X
Every 2 years
If the contactors are operated in particularly dirty envi-
ronments, the checking intervals for visible inspections
should be shortened, because dirt can impair the insu-
lation clearances and there is therefore the possibility
of a shorter service life or an operational fault.
Extraordinary services need only be carried out if there
has been a significant and extraordinary recorded num-
ber of switchings under fault conditions.
DANGER
When damages on the contactor, cables
or busbars are visible, the safety of the
contactor is no longer guaranteed.
X
Immediately give damaged con-
tactors or components to correc-
tive maintenance.
NOTICE
Detent-edged rings and detent-edged washers have
a limited life time. After 3 times opening of screws
secured with detent-edged rings or detent-edged
washers, the rings or washers must be replaced by
new ones.
X
Record the frequency of screw opening in the
work log.
X
After 3 times opening of screws, replace detent-
edged rings or detent-edged washers by new
ones.
