User Manual, Power contactors, series CT1115/08 and CT1130/08
Rev. 2.2
Page 19/26
Maintenance
CT1000 contactors are maintenance-free within the rated mechanical
life time. The electrical life time depends on the number of switchings
under heavy load conditions and may vary for different applications.
In normal use, this corresponds to a decade-long operating period.
Recommended regular
service intervals
Checking activity designation
Checking interval
Optical inspection from outside
1x annually
Inspection of the main contacts
1x to 2x annually depending on ap-
plication
Inspection of the auxiliary contacts
Every 2 years
Unscheduled service in-
tervals
Inspection activities
High voltage supply cables or current bars
Check of the high voltage supply cables/bars and the tightening torques of
the fastening screws.
Earthing
Check of the supply cables and the tightening torques of the fastening
screw.
Cleaning
In case of excessive dirt the surface of the contactors should be cleaned.
Inspection of the main contacts
Disconnect the main terminals and remove the Upper Module. Inspect the
main contacts (both fixed and movable contacts).
It requires some experience to evaluate the state of the contacts. Even after
only a few switchings under load the contacts look used and “polluted” for
the inexperienced eye. Contacts need only to be replaced if the wear of the
contact tips is more than 70%.
Replace the Upper Module and secure it. Reconnect the main terminals.
Inspection of the auxiliary contacts
Disconnect the main terminals and remove the Upper Module.
Remove the protection cover. The auxiliary switches are visible for a simple
optical inspection from the outside (housings are clean and do not show
signs of short-circuits etc.). Under normal working conditions (no short cir-
cuit switching) the life time of the auxiliary switches exceeds those of the
contactors.
Replace the protection cap and the Upper Module and secure it. Reconnect
the main terminals.
Auxiliary switches S870 are not visible when you have removed the cap.
You will need to remove the 2 screws and lift the assembly for inspection.
Extraordinary services need only be carried out if there has
been a significant and extraordinary recorded number of
switchings under fault conditions.
If the contactors are being used in particularly dirty environ-
ments, the checking intervals for the optical inspection should
be shortened, because dirt can impair the insulation clear-
ances and there is therefore the possibility of a shorter ser-
vice life or an operational fault.
