SECTION 8-Contact Maintenance (Cont.)
8.2
CONTACT ADJUSTM ENT
AKR 30/30H & AKRU 30
The contact structure of the AKR 30 and the AKRU 30
breakers is slightly different from the AKR 30H. Referring to
Fig.
44
A & B, both structures use one moveable contact
arm, and two stationary arcing contacts. However, the
AKRJAKRU 30 uses three stationary main contacts and the
AKR 30H uses four.
The following wipe adjustment procedure is applicable
to all AKR-30/30H & AKRU-30.
1.
Open the breaker, remove arc quenchers.
2. Slow-close the breaker. The cam roller must be sup
ported by the cam and not the prop. Refer to section 5.3.
3. Select one pole and, using a flat or wire feeler gage,
measure the gap between the top contact and its pivot stud
as shown in Fig.
45.
As necessary, adjust the gap to 0.060
±
0.020 inch by turning the wipe adjustment nut shown in
Fig. 45 & 46.
4. Once the gap dimension is set, verify that the torque
required to just turn the adjustment nut is greater than 40
in-lbs. If less torque is required, carefully add LOCTITE
220 or 290 to the adjustment nut threads. Wipe off any
excess LOCTITE. Once t he LOCTITE is set, recheck the
torque (value u p to 40 in.-lbs.) but do not break loose.
5. Repeat above procedure on the other pole units.
6. Trip the breaker.
ADJUST GAP AT
MEASUREMENT
PO I N T TO
.060
±
.020 "
PIVOT
STUD
UPPER CONTACT
0.250 "
M EASU R E M ENT POI N T
FIG. 45
-
WIPE ADJUSTMENT
800
AMP
CONTACT STRUCTU RE
FIG. 46 - WIPE ADJUSTMENT NUT-800 AMP CONTACT STR UCTUR E
34
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