SECTION 8-Contact Maintenance (Cont.)
8.3 CONTACT ADJUSTM ENT
AKR30L, AKR50/50H & AKRU 50
The contact breaker shown i n Fig. 47 is used by
AKR30L and all AKR50 b reaker types. This structure
uses two movable contact arms. Each arm acts
against a stationary arcing, a stationary i ntermediate
and three stationary mains.
The following p rocedure is used to perform the wipe
adjustment.
1 . Open the breaker, remove arc q uenchers.
2. Arrange the b reaker for slow-closing.
3. Select one pole of the breaker and p lace a thin
sheet or strip of tough insu lating material , such as
mylar, over the stationary arcing and intermed iate
contacts. Th is strip should be about two i nches wide
and m ust p revent the arcing and intermediate contacts
from making contact when the breaker is closed .
4 . U sing the ratcheting maintenance handle, slow
close the breaker with the i nsulation held in p lace.
Examine the insu lation to make sure it "over-hangs"
below the i ntermediate contacts, but not enough to
cover the main contacts.
5. Attach a continuity checker (bell-set, light, or ohm
meter) between the upper and lower stud. The checker
should indicate continuity exists.
6. Facing the breaker, turn the wipe adjustment stud
shown in Fig. 47 clockwise until the checker indicates that
the main contacts are separated.
7. Turn the stud counter-clockwise until the main con
tacts j ust touch.
8. From this point, advance the stud counter-clockwise
270 degrees. This will be 4-1/2 flats.
9. Once the adjustment is complete, verify that the torque
required to j ust 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 the LOCTITE is set, recheck the torque
valve.
10. Trip the br�ker, remove the i nsulating strips.
1 1 . Repeat the above procedure on the other two poles.
FIG . 47 - 1 600 AMP CONTACT STRUCTURE
36
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