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PowerVac
5kV Vertical Lift
®
Chapter 10. Maintenance
Be sure to discharge the interrupter before re-
moving the interrupter assemblies. Removal and
re-assembly of complete interrupter assemblies
is recommended and adjustment is not nor-
mally required due to the design of the inter-
rupter operating rod insulator connection. The
interrupter assemblies should be returned to the
same location from which they were removed.
Replacement of individual vacuum bottles is not
recommended. Therefore, vacuum bottles are
not supplied as a replacement part.
10-8 Lubrication
Proper lubrication is important for maintaining
reliable circuit breaker performance. The ML-19
mechanism uses bearings which have a syn-
thetic lining in some locations. These bearings
do not require lubrication to maintain low fric-
tion, but lubrication does not harm them and
oiling lightly is recommended. Sleeve bearings
are used in some linkage locations and needle
or roller bearings are used for low friction on
the trip shaft and close shaft.
Bearings are lubricated during factory assem-
bly with grease and oil, but all lubricants have
a tendency to deteriorate with age. Providing a
fresh lubricant supply at periodic intervals is
essential to proper breaker operation, especially
where frequent operation may have forced lu-
bricant out of the bearing surfaces. Apply a
few drops of light synthetic machine oil such
as Mobil 1 at each bearing. Apply a coat of
0282A2048P009 grease on the four corners of
the closing spring guide where it enters inside
the spring. Metal-to-metal contact surfaces
should be cleaned and lubricated with
0282A2048P009 grease to provide cleanliness
and prevent oxidation.
Electrical primary contact surfaces also require
periodic lubrication to inhibit oxidation and
minimize friction. At each inspection and main-
tenance interval, do the following:
1. Wipe clean and coat lightly with
0282A2048P009 grease all silvered primary
contact surfaces such as the movable con-
tact rod of the interrupter and the primary
disconnect fingers.
2. Clean and coat lightly with 0282A2048P009
grease the pins of the secondary coupler.
Courtesy of NationalSwitchgear.com
10-9
Recommended
Maintenance
The following operations should be performed
at each maintenance check:
1. Perform a visual inspection of the breaker.
Check for loose or damaged parts.
2. Perform a slow closing operation de-
scribed under MECHANICAL CHECKING
AND SLOW CLOSING.
3. Check the erosion indicator and the wipe
and gap as described under DIMENSIONAL
CHECKS.
4. Perform the vacuum interrupter integrity test
as described under ELECTRICAL CHECKS.
5. Lubricate the breaker operating mechanism
as described under LUBRICATION.
6. Check the electrical operation of the breaker
using the portable test cabinet.
CAUTION: REPEATED OPERATIONS AT A
RATE EXCEEDING TWO PER MINUTE MAY
CAUSE CHARGING MOTOR OVERHEAT-
ING AND SUBSEQUENT MOTOR FAILURE.
7. Examine the movable contact rod as de-
scribed in Chapter 10-5.
8. If desired, perform the additional tests
(Megger, Primary and Secondary High Po-
tential, and Primary Circuit Resistance).
See ELECTRICAL CHECKS.
10-10 Breaker Timing & Speed
Check
Timing and speed checks are optional and also
depend on the level of maintenance performed.
Generally these tests are not required for nor-
mal maintenance. If a new mechanism has been
installed or extensive repair, replacement or
major disassembly has been performed, it is
recommended that these tests be performed.
To determine contact velocity, a travel transducer
and oscillograph are required. Optional travel
transducer and linkage system can be obtained
by contacting your local GE Sales Office by or-
dering part number 0144D1238G001. The travel
transducer apparatus can typically be installed
as shown in Figure 28. A typical travel trace
and interpretation are shown in Figure 26.
32
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