Siemens GMSG Instruction Manual page 39

Removal from switchgear
Prior to performing any inspection or
maintenance checks or tests, the circuit
breaker must be removed from the
switchgear. The "Installation checks and
initial functional tests" section (refer to
page 8) describes the removal procedure
in detail. The principal steps are repeated
here for information and guidance, but
without the details of the preceding
section.
1. The first step is to de-energize the
circuit breaker. Figure 32: Trip-control
pushbutton (lower button) illustrates
the location of the trip control on the
circuit breaker operator panel.
Depressing the trip pushbutton opens
the circuit breaker prior to removal
from the switchgear.
2. The second step in the removal
procedure is to de-energize control
power to the circuit breaker. Open the
control-power disconnect device.
3. Rack the circuit breaker to the
DISCONNECT position.
4. Perform the spring discharge check.
This is done by first depressing the red
trip pushbutton. Second, depress the
black close pushbutton. Third, depress
the red trip pushbutton again, and
observe the spring condition indicator.
It should read DISCHARGED.
5. Remove the circuit breaker from the
switchgear. Refer to page 10 of
"Installation checks and initial
functional tests" section of this
instruction manual for special
instructions and precautions regarding
removal of a circuit breaker not at floor
level.
6. The circuit breaker can be located
either on the floor or on a pallet. Each
circuit breaker has four wheels and
handles to allow one person to
maneuver the unit on a level surface
without assistance.
Checks of the primary power path
The primary power path consists of three
vacuum interrupters and three upper-
primary and three lower-primary
disconnects. These components are
checked for cleanliness and condition. The
vacuum interrupters are also checked for
vacuum integrity.
Some test engineers prefer to perform the
contact-erosion check during the manual-
spring charging check of the operator,
since charging of the springs is necessary
to place the contacts in the CLOSED
position. Also, the vacuum-integrity check
is usually performed in conjunction with
the high-potential test.
These instructions follow the
recommendation these tests (contact-
erosion/manual-spring charging check and
vacuum integrity/high-potential tests)
should be combined as described.
Cleanliness check
Figure 33: Type GMSG vacuum circuit
breaker showing vacuum interrupters and
primary disconnects (barriers removed) is
a side view of the type GMSG vacuum
circuit breaker with the outer-insulating
barriers removed to show the vacuum
interrupter and the upper- and lower-
primary disconnects.
All of these components must be cleaned
and free of dirt or any foreign objects. Use
a dry lint-free cloth. For stubborn dirt, use
a clean cloth saturated with isopropyl
alcohol (except on a vacuum interrupter).
For stubborn dirt on a vacuum interrupter,
use a cloth and warm water and a small
amount of mild liquid-household detergent
as a cleaning agent. Dry thoroughly using
a dry lint-free cloth.
Maintenance
Figure 32: Trip-control pushbutton
(lower button)
Figure 33: Type GMSG vacuum
circuit breaker showing vacuum
interrupters and primary
disconnects (barriers removed)
39