23
2021-07-15 / V1.0
Contactors C320K/C320S – Installation and Maintenance Manual
Maintenance
ATTENTION
Detent-edged rings and detent-edged washers have
a limited life time. After screws secured with detent-
edged rings or detent-edged washers have been
undone three times, the rings or washers must be
replaced by new ones.
X
Record the frequency of undoing of the screws
in the work log.
X
Replace detent-edged rings or detent-edged
washers with new ones after the screws have
been undone three times.
Regular tests/checks
All of the maintenance activities that may be carried out
on the contactors by skilled personnel are listed below.
Component
Tests/checks
Measures
Wires/busbars
Check for:
X
damaged wires, cable lugs
X
damaged insulation
X
damaged busbars
X
kinked or crushed wires
X
loose or missing fastening elements
X
correct tightening torque of the terminal screws
In case of faults:
X
immediately replace damaged wires
or cable lugs
X
immediately replace damaged bus-
bars
X
tighten loose fastening elements im-
mediately, replace missing fastening
elements
X
tighten the terminal screws to the
rated torque
Contactor housing
Check for:
X
dirt
X
loose or missing fastening elements
penetrations, holes in the housing wall
X
damage or wear
X
broken ceramic arcing plates (only for C320K)
In case of faults:
X
remove any dirt that may be present
X
tighten loose fastening elements im-
mediately replace missing fastening
elements
X
tighten a loose contactor immedi-
ately
X
if the contactor housing is damaged
or heavily worn replace the entire
contactor
X
if there are broken ceramic plates in
the arcing chamber replace the en-
tire contactor
Main contacts
(both stationary
contacts and moving
contact bridge)
Check for:
X
damage or wear
X
traces of combustion residue (slight soot deposits
permitted)
A certain level of experience is required to assess
the state of the contacts. Even after a few load
switching cycles, to a lay user the contacts appear
worn and the surroundings fouled. Replacement
of the contactor is only necessary after more than
50% of the contact material is burnt through.
In case of faults:
X
if more than 50% of the contact
material is burnt through, replace
the entire contactor, see section
“8.2
Preventive maintenance” /
“Checking
the main contacts”.