GE AKR-30 Series Maintenance Manual page 119

8 . 6 CONTACT R E P LAC E M E NT­
AKA 30/30H/30L & AKRU 30
Refer to Stationary Contact Identif ication , Section 8.5
before replacing any stationary contacts.
The stationary contacts are held in place by the contact
springs which pivot the contacts against the contact stop ,
refer to Fig . 45. To replace contacts :
1 . Remove the arc runner. It is secured by two screws
into the base and one screw into the contact stop.
2 . Release each contact spring by holding the contact,
extending the spri ng, and removing it from the contact. The
end pieces on each spring have a small hole for inserting a
spring puller. A suitable puller can be fashioned by forming
a hook on the end of a length of .062" diameter steel wire.
A spring puller is available for this use and may be
ordered under Cat. No. 286A81 68G 1 .
3 . Clean off the existing l u brication on the stud's pivot
area. Replace with a small amount of D50H D38 (MOBIL
28) before installing new contacts.
4. Torque the upper arc runner mounting screws to 4S
±
S i n-lbs. Torque the lower screw to 3S-40 i n-lbs.
The movable contacts are removed as follows, referring
to Fig. 46.
1 . Using a rig ht ang le tru-arc p l iers, remove the tru-arc
retai ner on the coupl ing pin. Drift out the coupling pin.
2. Remove the pivot pin hardware and spring from one
side of the pivot pin. Carefu l ly remove the pivot pin.
3. Slip out the contact arm.
4. Place a thin fi l m of DSOH D38 l ubrication on the pivot
surfaces of the new arm. Clean any exi sting l ubrication
from the pivot pin and place a small amount of DSOHD38
on it.
S. Install the new arm, insert the pivot pin, and replace
the pivot spring and hardware. Tighten the p ivot pin hard­
±
w are to 90 i n-lbs.
6. Install the cou pling pin and tru-arc retainer.
7 . Make the contact adjustment as per section #8.2.
8. 7 CONTACT R EP LACEMENT- AKR 30L,
AKR 50/SOH , AKRU 50 & AKRT 50
Refer to Stationary Contact Identification, Section 8.5,
before replacing any stationary contacts.
The stationary i ntermediate and main contacts are
replaced just l i ke the stationary contacts on the
ampere breakers. Refer to steps 2 & 3 in Section 8.6
Referring to Fig . 50A, SOB & SOC, the stationary arcing
contacts are replaced as follows.
1 . Remove the arc runner and the flat insulation
assembled underneath the arc runner. It i s secured with
four screws. When removing the lower screws, use care
not to damage or m i sp lace the insulating washer found
under each of these screws, see Fig. SOA.
2 . Remove the Arcing contact pivot. Clean off the exist­
ing lubrication found on the pivot area. Repl ace with
050HD38 (MOBIL 28) , see Fig. SOB.
3 . Remove the insu lating spacers, contact pin and arc­
i ng contacts, see Fig. 50C.
4. Reassemble the reverse of above. Make sure that the
insulating spacers and insu lating washers are properly i n­
stal led. Torq ue the arc runner hardware to 4S
The movable contacts are removed in a s i m i lar manner
as the 800 ampere breaker movable contacts. Refer to
Section 8.6. When removing the pivot pin from a 2000
ampere (AKRT 50/SOH) contact assembly, the pivot pin
from the opposite contact assembly m ust be s l ightly
removed. Th i s provides enough clearance to completely
remove the pivot pin.
I
INSULATING
WASHER
ARC R U N N E R
FIG. 500 -
STATIONARY CONTACT -1 600/2000 A M P
R E P LACEMENT CONTACT STR U CTUR E
BOO
±
S i n-l bs.
39