Siemens 3AH3 Instruction Manual page 41

Insulation and contact-resistance test
procedure
1. Observe safety precaution listed in the
danger and warning advisories for the
vacuum integrity check tests (refer to
pages 38-39).
2. Close the circuit breaker. Ground the
frame of the circuit breaker, and ground
each pole not under test. Use manual
charging, closing and tripping
procedures.
3. Apply the proper ac or dc (refer to Table
4) high-potential test voltage between a
primary conductor of the pole and
ground for one minute.
4. If no disruptive discharge occurs, the
insulation system is satisfactory.
5. After test, ground both ends and the
middle of each vacuum interrupter to
dissipate any static charge.
6. For drawout applications, connect all
points of the secondary disconnect with
a shorting wire. For stationary
applications, disconnect secondary
circuits for the operating mechanism by
disconnecting the multiple pin-plug at
the upper right corner of the operator,
and connect all pins on the operator side
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 voltage, gradually increase the
test voltage to 1,500 volts rms, 60 Hz.
Maintain test voltage for one minute.
Alternatively, the test may be conducted
at 1,800 volts rms for one second.
7. If no disruptive discharge occurs, the
secondary control insulation level is
satisfactory.
8. Disconnect the shorting wire, and
reattach the multiple pin-plug (if
applicable).
9. Perform contact-resistance tests of the
primary contacts. The resistance should
be read between the lower and upper
connection pads (refer to Figure 22).
Contact resistance should not exceed
the values listed in Table 5.
Inspection and cleaning of circuit breaker
insulation
1. Perform the spring-discharge check
(refer to page 9) on the circuit breaker
after all control power is removed. The
spring-discharge check consists of:
a) Pressing the red Open pushbutton
b) Pressing the black Close pushbutton
c) Pressing again the red Open
pushbutton.
All of these controls are on the circuit
breaker front panel (refer to Figure 1).
Visually verify the Discharged condition
of the springs.
2. Remove any inter-phase and outer-phase
barriers if furnished (applicable for
certain types only).
3. Clean barriers and post insulators using
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 checklist in the
installation checks and initial functional
tests section of this instruction manual
(refer to pages 9-10). 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 are fully
discharged, all fasteners and connections
are checked again for tightness and
condition.
Contact
Current rating
resistance
A
Micro-Ohms
1,200 35
2,000 30
3,000 30
Table 5: Maximum contact-resistance
41