29
Maintenance
Checks of the Spring Charging Motor
No additional checks of the spring charging motor are
necessary. Once every 10,000 operations, the motor
brushes need replacement (reference kit 18-658-612-886).
Use the operation counter as the basis for establishing the
operation frequency.
High-Potential Tests
The next series of tests (Vacuum Integrity Test and Insula-
tion Tests) involve use of high voltage test equipment. The
circuit breaker under test should be inside a suitable test
barrier equipped with warning lights.
Vacuum Integrity Check
A high potential test is used to verify the vacuum integrity
of the circuit breaker. This test is conducted on the circuit
breaker with its primary contacts in the Open position.
High Potential Test Voltages
The voltages for high potential tests are shown in
Table 3
.
Automatic Spring Charging Check — Control Power
Required
Repeat the automatic spring charging check described in
the section entitled Installation Checks and Initial Functional
Tests.
Primary tasks of this check are:
1. The circuit breaker is energized with control power for
this check.
2. De-energize the source of control power (
Figure 1
).
3. Install the circuit breaker end of the split plug jumper
over the secondary disconnect of the circuit breaker.
The split plug jumper has one male and one female
connector and cannot be installed incorrectly (
Figure 7
).
4. Install the switchgear end of the plug jumper over the
secondary disconnect block inside the switchgear
(
Figure 8
).
5. Energize the control power source.
6. When control power is connected to the circuit breaker,
the closing springs should automatically charge.
Visually verify that the closing springs are charged.
Note:
A temporary source of control power and test leads
may be required if the control power source has not been
connected to the switchgear. When control power is
connected to the GMI circuit breaker, the closing springs
should automatically charge.
Electrical Close and Trip Check – Control Power Required
A check of the circuit breaker control circuits is performed
while the unit is still connected to the switchgear by the
plug jumper. This check is made with the breaker energized
by control power from the switchgear.
1. Once the circuit breaker springs are charged, move the
switchgear Close/Trip switch to the Close position. There
should be both the sound of the circuit breaker closing
and indication that the circuit breaker contacts are
closed by the main contact status indicator.
2. As soon as the circuit breaker has closed, the
automatic spring charging process is repeated.
3. After a satisfactory close operation is verified, move
the switchgear Close/Trip switch to the Trip position.
Verify by both sound and contact position that the
contacts are open. Completion of these checks demon-
strates satisfactory operation of auxiliary switches,
internal relays and solenoids.
Hazardous voltages and high-speed
mechanical parts.
Can cause death, severe personal injury, or
property damage.
Follow safe procedures, exclude unnecessary
personnel and use safety barriers. Follow NFPA
70E requirements.
WARNING
High Potential tests employ hazardous
voltages.
Will cause serious injury or death.
Follow safe procedures, exclude unnecessary
personnel and use safety barriers. Keep away
from the circuit breaker during application of
test voltages. Follow NFPA 70E requirements.
Disconnect the plug jumper from between the
circuit breaker and switchgear before
conducting high potential tests.
After test completion, ground both ends and
the middle portion of the vacuum interrupter
to dissipate any static charges.
DANGER
Vacuum interrupters may emit X-ray
radiation.
Can cause personal injury.
X-rays can be produced when a high voltage is
placed across two circuit elements in a vacuum.
Keep personnel more than six (6) feet away
from a circuit breaker under test.
WARNING
N
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DC
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wa
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ve
e rre
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ffiicca
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n.. T
Th
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e d
de
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ess p
prro
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du
ucce
e h
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h p
pe
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ak
k v
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olltta
ag
ge
ess..
These high voltages will produce X-ray radiation. These devices also
show erroneous readings of leakage current when testing vacuum circuit
breakers.
