IB
6.1.12.1-1C
1
6
ABB
tightness of these retainers at the recommended
maintenance intervals. Install chutes as follows:
1. Remove the electronic trip unit to access the
retaining hardware (if applicable).
2. Remove the screws and retainers. Tilt each arc
chute forward at the top and lift to remove.
3. Install in reverse order. Do not overtighten the
screws to avoid breaking the retainer or chutes.
Tighten screws to a maximum of:
Frame Size
Maximum Torque
225, 600, & 800
35 lb-in
1600 & 2000
75 lb-in
Look at the damage that service has impacted on the
chutes. Examine the arc chute exterior and the arcing
chamber. Soot, uniform erosion, and discoloration are
normal observations associated with arcing.
Replace a chute when any:
•
The stationary arc runner has significant erosion.
•
Arc splitters have burn-through holes.
•
Moldings have broken functional features that
retain arc splitters or baffle parts.
•
Shell moldings have mating surface defects that
may allow interruting gases to escape (flashover
potential).
Clean outside shell and arcing chamber region with a
clean cloth and denatured alcohol.
Contact Structure
Examine contact members for cracks and erosion.
Replace members with body cracks or broken
sintered contacts. Consider replacement of an arcing
contact member when the thickness of the sintered
arcing material has eroded to less than 50% of its
new thickness. Replace a main contact member if it
has erosion that cannot be dressed sufficiently to re-
establish a smooth surface. Likewise, inspect the
condition of the stationary contacts for erosion.
Check the mating primary disconnect surface of the
terminal studs for signs of burning.
If contacts need conditioning:
1. Avoid getting debris into the mechanism during
the cleaning and dressing process.
2. Remove bulk residue on contacts with a lint-free
cloth. Remove small burrs on contacts by filing
along the contour of the contact. Clean with
denatured alcohol.
3. Re-establish proper contact pressure and
simultaneous-make.
Control Circuitry
Inspect wiring for damaged insulation. Clean any
grease from the insulation. Check that wire routings
are protected from sharp edges. Confirm that lugs
and terminals are securely fastened. Confirm correct
wiring with preoperative checks that use the
connected device. If an electrical malfunction is
detected, compare the physical wiring configuration
against the schematic diagram of Figure A1 of
Appendix A. Test dielectric integrity with a Withstand-
Voltage Test as outlined in the
Insulation Withstand
section.
Disconnects
Inspect the primary disconnects for corrosion and
signs of over-heating. Remove the old NO-OX-ID “A-
Special” grease using a petroleum solvent (as
suggested by Sanchem) followed by a clean cloth
and denatured alcohol. Confirm that assemblies
were not damaged while servicing the breaker.
Reapply the NO-OX-ID “A-Special” only to the
switchgear end of the primary disconnect assemblies
where sliding contact occurs.
Inspect the secondary assemblies for a broken
plastic housing. Wipe clean, but do not lubricate the
secondary disconnect contacts. Identification of the
contacts can be determined from Figure A2 of
Appendix A.
Fasteners
Check the circuit breaker for loose, broken, or missing
fasteners. Locking type fasteners should be replaced
when removed. Torque hardware when indicated in
the bulletin.
Lubrication
Inspect existing grease to determine whether it should
be replaced. Discolored grease indicates oxidation
and contamination. Dry, caked grease has no
lubricating qualities and must be replaced.
As supported by service history and periodic
endurance testing, use only the greases approved by
ABB for use in K-Line circuit breakers. The approved
greases and application are as follows:
1. NO-OX-ID “A-Special” grease manufactured by
Sanchem, Inc. is a corrosion and water inhibitive
coating applied to the mating and working
surfaces of primary current path parts. Maintain
application on the primary disconnects, contact
structures, and any other primary current path
parts during maintenance intervals. Do not apply
NO-OX-ID “A-Special” to any secondary circuitry.
CAUTION
Do not apply NO-OX-ID grease on the parting surfaces of the
main or arcing contacts; may increase the interface resistance,
as well as, collect contaminating debris. The wiping action and
contact pressure were designed to maintain the interface.
2. Anderol 757 synthetic grease manufactured by
Huls America, Inc. is applied to moving surfaces
and for packing bearings.
