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Figure 34: Primary disconnect in
mated position
Number of
years/closing
Circuit breaker
operations
type
(whichever
comes first)
Non-generator circuit breakers
10-years/
GMSG
10,000
up to 50 kA
operations
10-years/
GMSG
10,000
63 kA
operations
Generator circuit breakers
10-years/
GMSG-GCB
10,000
40 kA
operations
10-years/
GMSG-GCB
10,000
50 kA
operations
10-years/
GMSG-GCB
10,000
63 kA
operations
Table 2: Maintenance and
lubrication schedule
40
Inspection of primary disconnects
Figure 34: Primary disconnect in mated
position shows the primary-disconnect
contact-fingers engaged. When the contacts
are mated with the switchgear primary-stud
assembly, there is forceful contact distributed
over a wide area. This maintains low-current
flow per individual contact finger.
Inspect the contact fingers for any evidence
of burning or pitting that would indicate
weakness of the contact-finger springs.
Inspect the primary-disconnect arms for
physical integrity and absence of mechanical
damage.
Inspect the flexible connectors that connect
the bottom movable-contacts of the vacuum
interrupters to the lower primary-disconnect
arms for tightness and absence of mechanical
damage, burning or pitting.
Using a clean cloth saturated with isopropyl
alcohol, clean old lubricant from primary
disconnects, and apply a very thin layer of
Siemens contact lubricant (reference 15-172-
791-233).
Checks of the stored-energy operator
mechanism
The stored-energy operator checks are
divided into mechanical and electrical checks
for simplicity and better organization. This
first series of checks determine if the basic
mechanism is clean, lubricated and operates
smoothly without control power. The contact-
erosion check of the vacuum interrupter is
also performed during these tasks.
Maintenance and lubrication
Table 2: Maintenance and lubrication
schedule gives the recommended
maintenance intervals for circuit breakers.
These intervals assume the circuit breaker is
operated under "usual service conditions" as
discussed in ANSI/IEEE C37.20.2, section 8.1,
and C37.04, section 4, together with
C37.010, section 4 for type GMSG non-
generator circuit breakers. For type GMSG-
GCB generator circuit breakers, these service
conditions are defined in ANSI/IEEE C37.20.2,
section 8.1 and ANSI/IEEE C37.013, section
4.2. The maintenance and lubrication interval
is the lesser of the number of closing
operations or the time interval since last
maintenance.
The vacuum-interrupter operator mechanism
is shown in Figure 35: Operator mechanism
lubrication on page 41, with the front cover
and the operator-control panel removed to
show construction details.
Both the tripping spring and the closing
spring are shown. The movable end of the
closing spring is connected to a crank arm.
The movable end of the opening spring is
connected to the jack shaft by a pull rod.
Clean the entire stored-energy operator
mechanism with a dry, lint-free cloth.
Check all components for evidence of
excessive wear.
Place special attention on the closing spring-
crank and the various pushrods and linkages.
Lubricate all non-electrical moving or sliding
surfaces with a light coat of synthetic grease
or oil.
Lubricants composed of ester oils and lithium
thickeners will generally be compatible.
For all lubrication (except electrical
moving or sliding surfaces), use one of the
following:
Klüber Isoflex Topas L32
(part 3AX11333H)
Klüber Isoflex Topas L32N (spray)
(part 15-172-879-201).
Source:
Klüber Isoflex Topas L32 or L32N:
Klüber Lubrication North America L.P.
www.klueber.com.
Primary-disconnect contacts (multi-fingered
clusters) and secondary- disconnect contacts
(strips and fingers) are to be wiped clean, and
a film of Siemens contact lubricant (15-172-
791-233) applied. Avoid getting contact
lubricant on any insulating materials.
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