Siemens GMSG Instruction Manual page 11

Installation checks and functional tests
3. Rotate the racking crank
counterclockwise until the circuit
breaker is in the DISCONNECT position.
4. Open the circuit breaker compartment
door, slide the covers to the side that
allow the circuit breaker to roll out of
the cell, and insert the two extension
rails into the fixed rails. Be sure the
extension rails are properly secured in
place.
Figure 3: Use of extension rails for
removal of circuit breaker not at floor
level shows the two extension rails
inserted into the fixed rails within the
cell. The rails engage locking pins in
the fixed rails to secure them in
position. The photo shows use of the
extension rails in a lower cell installed
above floor level. The procedure is
similar for an upper circuit breaker cell.
5. Depress and hold down the circuit
breaker racking latch release handle
and pull the circuit breaker out from
the DISCONNECT position. The circuit
breaker can now be removed from the
cubicle and rolled out onto the two
extension rails.
6. Remove the circuit breaker from the
two extension rails using the approved
Siemens circuit breaker lifting device or
Siemens lifting sling and a suitable
crane.
7. Lift the two extension rails and
withdraw them from the switchgear.
Heavy weight.
Can result in death, serious injury or property damage.
Do not transport a circuit breaker using a lift truck with the lift
truck in the raised position.
8. For arc-resistant type GM-SG-AR
switchgear, return the covers that
allow the circuit breaker to roll out of
the cell to their original position. Close
the circuit breaker compartment door
and secure all latches.
Type GMSG vacuum circuit breakers weigh
between 430 and 834 lbs (195-379 kg)
depending upon ratings. The circuit
breaker can be moved using a properly
rated crane and lift sling. A lift sling can be
attached to the circuit breaker, and then
used to hoist the circuit breaker vertically
clear of the extension rails. When clear,
remove the rails and lower the circuit
breaker to the floor.
Racking crank engagement procedure
A crank for racking the circuit breaker is
provided as a standard accessory. Racking
a circuit breaker can be accomplished with
the drawout compartment front door open
(for type GM-SG non-arc-resistant
switchgear) or through a small opening (or
window) in the front door, with the door
closed.
The racking crank consists of an offset
handle with a custom socket assembly
welded to the end. The socket end of the
crank is designed to engage the shoulder
of the racking-mechanism shaft and
remain engaged during racking with spring
plungers. The plungers operate in a
manner similar to the retainers of an
ordinary mechanic's socket wrench.
Figure 2: Type GMSG vacuum circuit
breaker racking
Figure 3: Use of extension rails for
removal of circuit breaker not at
floor level
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