22
BEFORE REMOVING THE FACEPLATE, HOOK THE UPPER AND
LOWER SPRINGS OVER THE FLOATING TRIM. THIS WILL RETAIN THE
FLOATING TRIM WHEN THE FACEPLATE IS REMOVED. ONCE THE
FACEPLATE HAS BEEN REMOVED, PULL THE FLOATING TRIM OFF AND
REMOVE THE BOX ASSEMBLY. No FURTHER DISASSEMBLY
IS REQUIRED FOR NORMAL MAINTENANCE.
3. CLEAN BREAKER
CLEAN THE BREAKER WITH AIR PRESSURE, A BRUSH, DRY CLOTH
OR VACUUM CLEANER. REMOVE ACCUMULATED DIRT FROM ALL
ACCESSIBLE SURFACES. WIPE EXCESS GREASE FROM THE DRAWOUT
WHEELS.
4. CLEAN MAIN AND SECONDARY DRAWOUT CONTACTS
REMOVE ANY GREASE THAT HAS BECOME DIRTY AND CAKED ON
THE MAIN AND SECONDARY DRAWOUT CONTACTS AND GROUND
CONTACT. WIPE EACH PART CLEAN BUT DO NOT USE CONTACT
CLEANER SPRAY AS THIS MAY DAMAGE ADJACENT PLASTIC PARTS.
5. INSPECT MOULDINGS AND HARDWARE
STARTING AT THE REAR OF THE BREAKER, INSPECT THE UPPER
AND LOWER MOULDINGS FOR CRACKS OR SIGNS OF DAMAGE FROM
OVER- HEATING. CHECK THAT ALL HARDWARE IS TIGHT, IN
PARTICULAR, THE MOUNTING SCREWS OR BOLTS FOR DRAWOUT
CONTACTS. CHECK THAT THE MAIN AND SECONDARY DRAWOUT
CONTACTS ARE FREE TO MOVE UP AND DOWN FOR SELF ALIGNMENT
AND CHECK THAT THE WIRE CONNECTIONS TO THE SECONDARY
CONTACTS ARE INTACT.
MOVING TO THE FRONT Of THE BREAKER, AGAIN CHECK THE
MOLDINGS AND HARDWARE. LOOK FOR MISSING RETAINERS ON THE
PINS IN THE MOVING CONTACT ASSEMBLIES AND CLOSING
MECHANISM.
6. INSPECT ARCING CONTACTS
THE MOVING AND STATIONARY ARCING CONTACTS ARE
SUBJECTED TO EROSION EVERY TIME CURRENT IS INTERRUPTED. THEY
NEED ONLY BE REPLACED IF THEY SHOW SEVERE PITTING OR
MATERIAL LOSS. BECAUSE OF THEIR WIPING ACTION, THE ARCING
CONTACTS DO NOT REQUIRE CLEANING.
7. INSPECT BRAIDS
CHECK THE BRAIDS ATTACHED TO THE MOVING ARCING
CONTACTS. If THEY ARE DISCOLORED, IF STRANDS ARE BROKEN OR IF
THEY DO NOT FEEL FLEXIBLE, THEY SHOULD BE REPLACED.
8. INSPECT MAIN CONTACTS
CHECK THE MOVING AND STATIONARY MAIN CONTACTS
SURFACES. WIPE THE CONTACTS CLEAN AND INSPECT VISUALLY.
SLIGHT PITTING AND ROUGHNESS WILL OCCUR NORMALLY DURING
LOAD SWITCHING. RUB YOUR FINGER OVER EACH CONTACT SURFACE.
THIS CAN REVEAL IRREGULARITIES NOT READILY VISIBLE. BADLY
PITTED OR SCORED CONTACTS SHOULD BE REPLACED. CLEAN THE
CONTACT SURFACES WITH THE FIBRE ABRASIVE. NEVER USE STEEL
WOOL FOR CLEANING BREAKER CONTACTS.
ON THE MOVING CONTACT ASSEMBLY, CHECK THAT EACH
WAFER MOVES
FIG. REMOVING FACEPLATE
F
FIG. 7.3.2.1 PARTS TO BE REMOVED FOR MAINTENANCE
1 . LOWER FLASH SHIELD
2
.
INTERPHASE BARRIER
3. ARC CHUTE
4. FRONT FLASH SHIELD
5. FACEPLATE
6. FLOATING TRIM
7. FACEPLATE BOX
REMOVE THE ARC CHUTES INSPECTING EACH CHUTE AS IT IS
REMOVED. DISCOLORATION IN THE TOP AND INTERIOR SURFACES
ARE NORMAL. THE ARC CHUTE ONLY NEEDS TO BE REPLACED IF
HEAVY DEPOSITS OF ARC MATERIAL ARE PRESENT OR IF IT IS
CRACKED OR DISTORTED. NEXT REMOVE THE LOWER FLASH SHIELDS
FROM BENEATH THE FIXED ARCING CONTACTS AND AGAIN INSPECT
EACH FOR DAMAGE
.
REMOVE THE FRONT FLASH SHIELD. ON 14 AND 27 INCH FRAME
BREAKERS, THE END BARRIERS WILL COME OFF WITH THE FRONT
FLASH SHIELD. ON 21 INCH BREAKERS THE END BARRIERS NEED NOT
BE REMOVED. FINALLY, LIFT OFF THE INTERPHASE BARRIERS. CHECK
ALL THESE PARTS FOR DAMAGE.
