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2021-07-15 / V1.0
Maintenance
Contactors C320K/C320S – Installation and Maintenance Manual
Component
Tests/checks
Measures
Auxiliary switches
S870
Check for:
X
dirt
X
damage or wear on the housing
X
signs of short circuits
The auxiliary switches can be accessed from the
outside for a simple visual inspection.
Under normal operating conditions (there have
been no short circuits in the control circuit)
there is no general need to replace the auxiliary
switches.
However, in the event of a short circuit in the con-
trol circuit, it is possible that the auxiliary switches
may be damaged and need to be replaced.
In case of faults:
X
replace the auxiliary switches,
see section
“8.3 Corrective mainte-
nance”
/
“Replacing the S870 auxil-
iary switches”
Checking the main contacts
The housing of the contactor has inspection openings
on both narrow sides (1) through which the main con-
tacts can be inspected.
Safety
DANGER
Before starting work on the contactors,
make sure that
X
no voltage is present,
X
all safety regulations are fully ob-
served.
X
Be sure to observe chapter
“3. Hazards and safety precautions”
on page 6
.
Tools required
-
Torch
-
Inspection mirror
Procedure
X
Check the main contacts through the inspection
openings (1). In doing so check both
-
the stationary contacts (2),
-
as well as the contacts (3) on the moving con-
tact bridge.
X
To get a better view of the contacts use a torch and
an inspection mirror.
X
If more than 50% of the contact material is burnt
through, replace the contactor as a whole unit.
1
3
2
Fig. 17: C320K: Checking the main contacts
1
3
2
Fig. 18: C320S: Checking the main contacts
