8
FIG. 4.1.4 DRAWOUT MECHANISM
1.
GATE
2.
CRANK SOCKET
3.
DRAWOUT LEVER BUSHINGS
4.
CRADLE DRAWOUT SLOTS
TO OPERATE THE DRAWOUT MECHANISM, THE GATE 1S
LOWERED TO EXPOSE THE CRANK SOCKET, AND THE DRAWOUT
CRANK INSERTED. THE GATE IS INTERLOCKED TO BOTH THE
CHARGING AND TRIPPING MECHANISMS OF THE BREAKER, SUCH
THAT IF THE MAIN SPRING IS CHARGED, IT WILL BE DISCHARGED AND
IF THE CONTACTS ARE CLOSED, THE BREAKER WILL BE TRIPPED. AS
LONG AS THE GATE IS DOWN, THE CONTACTS CANNOT BE CLOSED.
AN ADDITIONAL INTERLOCKING MECHANISM WILL NOT ALLOW THE
GATE TO BE RAISED IF THE BREAKER IS PART WAY BETWEEN TEST
AND OPERATION POSITIONS.
THIS WAY THE MAIN SPRING WILL ALWAYS BE
DISCHARGED AND THE CONTACTS OPEN WHEN THE BREAKER IS
BEING DRAWN IN OR OUT OR WHEN IT IS LEFT BETWEEN TEST AND
OPERATING POSITION.
NOTE THAT LOWERING THE GATE WITH THE MAIN SPRING
CHARGED, OR MANUALLY CHARGING THE SPRING WITH THE GATE
LOWERED, WILL RESULT IN A "DRY RUN", THAT IS, THE SPRING
DISCHARGES WITHOUT CLOSING THE CONTACTS. THIS
IS A SAFETY FEATURE AND DRY RUNS DURING DRAWOUT OPERATION
MAY SOMETIMES BE UNAVOIDABLE, BUT BECAUSE THEY STRESS THE
MECHANISM TO A GREATER EXTENT THAN NORMAL OPERATIONS,
DRY RUNS SHOULD BE AVOIDED IF POSSIBLE.
REFER TO SECTION 4.8.
TO INSTALL A BREAKER PROCEED AS FOLLOWS:
-OPEN THE CUBICLE DOOR AND FOLD DOWN THE RAILS
-PLACE BREAKER ON THE RAILS AND ROLL IT INTO THE CRADLE
-FOLD THE RAILS UP AND FULLY CLOSE THE DOOR
-INSERT THE DRAWOUT CRANK AND TURN CLOCKWISE UNTIL
THE BREAKER IS IN THE TEST POSITION AS SHOWN IN FIG. 4.1.2 OR IN
THE OPERATING POSITION AS SHOWN IN FIG. 4.1.3 AND REMOVE THE
CRANK. WHEN CRANKING THE BREAKER INTO THE OPERATING
POSITION, CONTINUE CRANKING UNTIL THE MECHANISM COMES TO A
FIRM STOP.
TO REMOVE A BREAKER, THE PROCEDURE IS JUST THE
OPPOSITE TO THE ABOVE. BEFORE INSERTING THE DRAWOUT
CRANK, REFER TO SECTION 4.8 TO AVOID UNNECESSARY DRY RUNS.
FOR DRAWOUT GATE ADJUSTMENT REFER TO SECTION 8.4.
4.2 GROUNDING CONTACT
GROUNDING CONTINUITY IS ESTABLISHED 1/8" (3.2
mm)
BEFORE
SECONDARY CONTROL CONTACTS ARE ENGAGED IN THE "TEST"
POSITION. IT IS MAINTAINED THROUGHOUT BREAKER POSITIONING IN
THE ENCLOSURE UNTIL THE SECONDARY CONTROL CONTACTS HAVE
BEEN SEPARATED AGAIN BY THE SAME DIMENSION. GROUNDING
CONTINUITY IS ESTABLISHED WHEN THE MOVING GROUND CONTACT
ON THE BREAKER (FIG. 3.1 ITEM 61) MATES WITH THE STATIONARY
GROUND STAB LOCATED ON THE CRADLE (FIG. 3.2 ITEM 7).
4.3 SECONDARY CONTROL CONTACTS
SECONDARY CONTROL CONTACTS AUTOMATICALLY CONNECT
OR DISCONNECT CONTROL CIRCUITS AS THE BREAKER MOVES
THROUGH ITS DRAWOUT POSITIONS. A TOTAL of 40 CONTACTS CAN BE
PROVIDED ON 14" WIDE BREAKERS (MAXIMUM 1600 AMPS) AND 21"
WIDE BREAKERS EQUIPPED WITH MECHANICAL INTERLOCK
(MAXIMUM 2000 Amps). ALL OTHER BREAKERS CAN BE PROVIDED WITH
48 CONTACTS. EACH CONTACT HAS A CONTINUOUS CURRENT RATING
OF 30 AMPS. IN APPLICATIONS WHERE A CONTROL VOLTAGE SUPPLY IN
EXCESS OF 250V IS TO BE USED, THE SECONDARY CONTACTS ARE
DOUBLE-SPACED, (I.E. ADJACENT CONTACTS ARE OMITTED).
THE FIXED (CRADLE MOUNTED) CONTACT ASSEMBLIES MAY
BE SUPPLIED WITH ELECTRICALLY SEPARATED OR JUMPERED "TEST" AND
"OPERATING" POSITION CONTACTS TO PROVIDE A VARIETY OF
OPTIONAL CONTROL FUNCTIONS, IE. ISOLATION, BYPASS, ETC.
