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Circuit Breaker Position
HAND
POSITION
HAND
POSITION
SPRING PLUNGER
SPRING PLUNGER
CRANK ROTATED
FOR CLARITY
ARTICULATED JOINT
CUSTOM SOCKET
SPRING PLUNGER
Figure 42. Racking Crank Engagement Procedure
Breaker Racking
When inserting a circuit breaker into a cell, be sure that the
racking block is in the lowered position as shown in Figure 43.
In this position, the racking position indicator should show a
green square with the letter "D" for DISCONNECT position. If
the racking block is in the raised position, Figure 44, use the
racking crank to move the racking block to the lowered position.
Important: Failure to follow instructions may result in
damage to equipment.
Return racking mechanism to the DISCONNECT position
before inserting circuit breaker.
Figure 43. Racking Mechanism with Racking Block Down
Figure 44. Racking Mechanism with Racking Block Up
42
Courtesy of NationalSwitchgear.com
SOCKET ASSEMBLY
RACKING MECHANISM SHAFT
SHOULDER PORTION OF SHAFT
Racking Block Down
1557-95
Racking Block Down
1558-95
The circuit breaker racking method has been designed to be
used with the instrument door either open or closed. Moving
the breaker between the CONNECT and TEST or DISCONNECT
positions with the door closed provides additional protection to
the operator and is the recommended procedure.
Racking from DISCONNECT to CONNECT Position
1. Check the position indicator shows "D" for DISCONNECT
position.
2. Check that the circuit breaker is fully pushed into the cell
to the DISCONNECT position.
3. Check that the circuit breaker is OPEN.
4. Secondary disconnects will automatically connect as the
circuit breaker moves to the TEST and CONNECT position.
5. Close instrument door.
6. Insert racking crank through round opening at bottom of
door and onto the racking screw (see "Racking Crank
Engagement Procedure").
7. Push the racking crank forward to move the closed breaker
racking interlock slide back which will allow the socket to
engage the hex head on the racking screw. Do not force
slide as it is interlocked to prevent sliding forward when
the circuit breaker is closed.
8. Rotate the racking crank clockwise about 54 turns until a
positive stop is felt and the position indicated shows "C"
for the CONNECT position. The indicator will show "T"
when the circuit breaker is in TEST position.
Racking from CONNECT to TEST or DISCONNECT
Position
1. This procedure is essentially the same as racking to con-
nected position procedure except the rotation is counter-
clockwise.
2. Check that the circuit breaker is open.
3. Close instrument door.
4. Insert racking crank (see "Racking Crank Engagement
Procedure") and rotate counterclockwise about 54 turns
to a positive stop and the position indicator indicates "D"
for DISCONNECT position. The intermediate TEST position
is indicated by "T".
Contact Penetration
Make certain all electrical connections to both the line/load and
bus disconnects are de-energized and locked out. This can be
verified by blocking the shutters open and using a hot stick
potential device to double-check that all disconnects are de-
energized. Rack the breaker completely into the CONNECT
position and then withdraw it from the cell. Check that the
contact wipe is about 3/8" (10mm) on the cell primary discon-
nects, for all breaker ratings.
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