31
FIG. 8.7, LATCH CHECK SWITCH
1 . TRIP SHAFT LEVER
2. TRIP SHAFT STOP SCREW
3. LATCH CHECK SWITCH
4. MOUNTING PLATE
5. PIVOT SCREW
6. LOCKING SCREW
8.8 MECHANICAL INTERLOCK
TO CHECK THE OPERATION OF THE MECHANICAL INTERLOCK
MECHANISM, REMOVE THE BREAKER FROM THE CELL. ROTATE THE
CLOSING SHAFT BY USING THE SLOW CLOSE DEVICE. THE UPPER
PLUNGER CONNECTED BY CABLE TO THE CLOSING SHAFT SHOULD
MOVE FREELY. BY PUSHING THE LOWER PLUNGER, ITS CABLE
EXTENSION SHOULD PUSH THE TRIP SHAFT LEVER ON RIGHT SIDE OF
THE MECHANISM AND ROTATE THE TRIP SHAFT TO DISENGAGE TRIP
LATCH AND LATCH ROLLER. MAKE SURE THE THAT WHEN LOWER
PLUNGER IS RELEASED, IT MOVES FREELY TO ITS FULLY RESET
POSITION. IN THIS POSITION THERE SHOULD BE APPROXIMATELY1/16"
(1.6 MM) CLEARANCE BETWEEN TRIP SHAFT LEVER AND CABLE, CLOSE
THE BREAKER, THEN PUSH LOWER PLUNGER IN SLOWLY TO MAKE
SURE BREAKER TRIPS. IF THE PLUNGERS DO NOT MOVE FREELY, THE
CABLE MUST BE REMOVED FROM THE SHEATH AND CLEANED TO
RESTORE FREE MOVEMENT.
8.9 ANTI-SINGLE-PHASE DEVICF AND BLOWN FUSE INDICATOR
A SIMPLE MECHANICAL CHECK OF PROPER OPERATION OF THE
UNIT CAN BE MADE BY FIRST CLOSING THE BREAKER THEN RAISING
EACH PLUNGER BY HAND SLOWLY. WHEN THE BREAKER TRIPS, THE
PLUNGER SHOULD OVERTRAVEL SLIGHTLY BEFORE REACHING THE
END OF ITS STROKE. AN ELECTRICAL TEST MAY BE PERFORMED BY
MEANS OF A SINGLE PHASE VARIABLE AC SOURCE, 250 VA OR LARGER.
THE TEST SIGNAL IS APPLIED DIRECTLY TO THE TRIP COIL TERMINAL
AFTER FIRST REMOVING THE THREE CONTROL FUSES IN THE CIRCUIT.
THIS IS NECESSARY TO ISOLATE THE TRIP COIL FROM THE POWER
FUSE. THE COIL SHOULD OPERATE AT APPROXIMATELY 50 VOLTS. IN
THIS TEST IT SHOULD BE NOTED THAT THESE COILS ARE SHORT-TIME
RATED IN NORMAL OPERATION ARE DE-ENERGIZED THE INSTANT THE
THE STRIKER AS REOUIRED TO PROVIDE A GAP OF
APPROXIMATELY 5/16 INCH (8-MM) BETWEEN THE STRIKER AND
THE TRIP SHAFT LEVER. TIGHTEN THE LOCKNUT FIRMLY.
A VERNIER TIME ADJUSTMENT IN THE FORM OF AN
ECCENTRIC IS PROVIDED FOR FINE AJUSTMENT, INDEPENDENT
OF THE SCALE SETTING. IF TRIMMING IS REOUIRED, LOOSEN
THE LOCKNUT LOCATED ON THE INSIDE OF THE LEVER AND
TURN THE ECCENTRIC COUNTER-CLOCKWISE TO INCREASE
TIME, AND CLOCKWISE TO SHORTEN TIME. THE LOCKNUT MUST
BE FIRMLY TIGHTENED EACH TIME THE ECCENTRIC IS MOVED.
FIG 8.6.1, UNDERVOLTAGE TRIP DEVICE
1.
STRIKER
2.
TRIP SHAFT LEVER
3.
TIMER
4.
VERNIER TIMER ADJUSTMENT
8.7 LATCH CHECK SWITCH
THE LATCH CHECK SWITCH IS ADJUSTED AS FOLLOWS:
WITH THE BREAKER OPEN AND THE CLOSING SPRING
DISCHARGED, GENTLY RAISE THE TRIP SHAFT LEVER UNTIL
OPERATION OF THE LATCH CHECK SWITCH CONTACTS CAN BE
HEARD. RELEASE THE TRIP SHAFT LEVER.
THESE SHOULD BE APPROXIMATELY 1/8 INCH OVERTRAVEL (AT
THE TIP OF THE SWITCH OPERATING LEVER) FROM THE POINT WHEN
THE CONTACTS OPERATE, TO THE POINT WHEN THE TRIP SHAFT
LEVER IS RELEASED AND RESTS AGAINST ITS STOP SCREW.
IF ADJUSTMENT IS REQUIRED, LOOSEN THE PIVOT SCREW AND
LOCKING SCREW AND RAISE OR LOWER THE SWITCH AS REQUIRED.
RETIGHTEN BOTH SCREWS FIRMLY.
IN NORMAL OPERATION THE LATCH CHECK SWITCH SHOULD
REQUIRE NO RE-ADJUSTMENT, BUT IF THE TRIP LATCH ADJUSTMENT
IS ALTERED, THE LATCH CHECK SWITCH SETTING MUST BE CHECKED
AS ABOVE.
