Siemens vacuum circuit breaker 38-3AH3 38 kV - Manual (Page 52)

Maintenance
7. Connect all points of the secondary
disconnect with a shorting wire.
Connect the shorting wire to the high-
potential lead of the high-voltage
tester and ground the circuit-breaker
housing. Starting with zero volts,
gradually increase the test voltage to
1,500 volts rms, 60 Hz. Maintain test
voltage for one minute.
8. If no disruptive discharge occurs, the
secondary-control insulation level is
satisfactory.
9. Disconnect the shorting wire and re-
attach the leads to the spring-charging
motor.
10. Perform contact-resistance tests of the
primary contacts (refer to Figure 45:
Contact-resistance test of the primary
contacts). Contact resistance should
not exceed the values listed in Table 4:
Maximum contact resistance.
Inspection and cleaning of circuit-
breaker insulation
1. Perform the spring discharge check on
the circuit breaker after all control
power is removed. The spring
discharge check consists of:
A. Depressing the red trip pushbutton
B. Depressing the black close
pushbutton, and
C. Depressing again the red trip
pushbutton.
All of these controls are on the circuit
breaker front panel. Visually verify the
DISCHARGE condition of the springs.
2. Remove phase barriers as shown in
Figure 7: Circuit breaker primary
disconnects on page 13.
3. Clean barriers and post insulators using
a clean cloth dipped in isopropyl
alcohol.
4. Replace all barriers. Check all visible
fasteners again for condition and
tightness.
Note: Do not use any cleaning compounds
containing chlorinated hydrocarbons such
as trichlorethylene, perchlorethylene or
carbon tetrachloride. These compounds
will damage the phenylene ether
copolymer material used in the barriers
and other insulation on the circuit breaker.
Functional tests
Refer to the "Installation checks and
functional tests" section of this instruction
manual on pages 8 to 13. Functional tests
consist of performing at least three manual
spring-charging checks and three
automatic spring-charging checks. After
these tests are complete, and the springs
fully discharged, all fasteners and
connections are checked again for
tightness and condition before re-installing
the circuit breaker into the metal-clad
switchgear.
Figure 45: Contact-resistance test of
the primary contacts
Continuous
current
rating (A)
Contact
resistance
(micro-ohms)
1,200 35
2,000 30
3,000 30
Table 4: Maximum contact
resistance
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