GE Industrial Solutions EntelliGuard 800–2000 A Frames, 240–600 Vac Maintenance Manual - Manual (Page 34)

EntelliGuard™ 800–2000 A Power Circuit Breakers
Chapter 6. Contact Maintenance
24
Contact Replacement on EGX08, EGS16,
EGF16, EGH16, EGS20, and EGF20 Breakers
For the following procedures, illustrated in Figure 20, the
breaker must be removed from its compartment and
placed on a suitable working surface. Remove the arc
chutes and interphase barriers, as described in Section
6.2.
Stationary Contacts
Use the following procedure to replace the stationary con-
tacts.
1. Remove the four screws holding the arc runner in
place and remove the arc runner. Take care not to
damage or lose the insulating washer underneath
the lock washer and flat washer on the two lower
screws.
2. For replacement of stationary main and intermedi-
ate contacts:
a. Release each contact spring by holding the corre-
sponding intermediate or main contact, extend-
ing the spring, and removing the spring from the
contact. The end pieces of each spring have a
small hole for inserting a spring puller.
b. Remove each contact as its spring is disengaged.
Clean off the existing lubricant on the pivot area.
Replace with a small amount of GE Lubricant
D6A15A1 (MobilGrease 28, catalog number
193A1751P1).
c. Insert each replacement main and intermediate
contact and secure with its contact spring. Note
that main and intermediate contacts are
differentiated by the number of chamfers on the
corners of the contact surfaces, as illustrated in
Figure 21. It is important that this distinction be
observed when replacing the contacts.
3. For replacement of stationary arcing contacts, as
illustrated in Figure 22:
a. Remove the two screws and lock washers securing
the arcing contact pivot to the assembly and
remove the pivot.
b. Remove the insulating spacers, contact pin, and
arcing contacts.
c. Insert the replacement arcing contacts, the con-
tact pin, and insulating spacers.
d. Place the arcing contact pivot in position and
secure with its two screws and lock washers.
4. Place the arc runner in position and secure with its
four screws. Ensure that the insulating washers are
in place on the lower screws. Tighten the screws to
45 in-lb.
Movable Contacts
Use the following procedure to replace the movable con-
tacts.
1. Remove the snap ring from the coupling pin and
slide out the pin.
2. Remove the screw, washer, and spring from one side
of the pivot pin. Carefully remove the pivot pin.
3. Slip out the contact arms.
4. Clean any existing lubricant from the pivot pin.
Place a small amount of GE Lubricant D6A15A1
(MobilGrease 28, catalog number 193A1751P1) on
the pivot pin and the pivot surfaces of the new
contact arms.
5. Install the new arm, insert the pivot pin, and replace
the pivot spring, washer, and screw. Tighten to 90
in-lb.
6. Install the coupling pin and secure with the snap
ring.
7. Adjust the contacts as described in Section 6.5.