Vacuum Integrity Test Procedure; As-Found Insulation And Contact Resistance Tests; Insulation And Contact Resistance Test Equipment - Siemens 3AH Series Instructions Manual

Mai n ten ance
Figure 18. Circuit Breaker Pole Assembly /Vacuum Check Mech anical / Contact Resistance Test
N ote: Do n ot use DC high potential testers incorporat­
ing half-wave rectification. T hese devices produce
high peak voltages.
These high voltages will produce X-ray rad iation.
These devices also show erroneous readings of leak­
age current when testing vacuum circuit breakers.
Vacuum lntegrityTest Procedure
1. Observe safety precautions l isted in the d anger a n d warn­
ing advisories. Construct the proper barrier and warn i n g
light system .
2. Ground each pole not u n der test.
3. Apply test voltage across each pole for one minute (Circuit
Breaker open).
4. If the pole sustains the test voltage for that period, its
vacu u m integrity has been verified.
Note: This test i ncludes not only the vacu um interrupter,
but also the other insulation components in parallel with the
vacuum interrupter. These include the post insulators
Prinary Contact
Res stance Test
Step 2
PrimarY Contac t
Closed Positi:l n - �nsulated
C ol-Per Dl!connected)
prinary contact
Open Position - (Forced
by tlar&.�al
Open Pressure)
In alingC oupleq
sui
(Operating Posti:ln)
(Lo.vered Position)
(Se p 2)
a n d the insulati ng coupler, as well as the insulating (tension )
struts between the upper and lower vacuu m i nterrupter sup­
ports. If these insu lation components a re contam i n ated or
defective, the test voltage will not be sustained. If so, clean
or replace the affected components, and retest.

As-Found Insulation and Contact Resistance Tests

As-Found tests verify the integrity of the circ u it breaker
insulation system . Megger or insulation resistance tests
conducted on equipment prior to installation provide a basis
of future comparison to detect changes in the protection
afforded by the insulation system. A permanent record of
periodic As-Found tests enables the maintenance organ iza­
tion to determine when corrective actions are req u ired by
watch ing for significant deterioration in insu lation resis­
tance, or increases in contact resistance.

Insulation and Contact Resistance Test Equipment

In a ddition to the High PotentiaiTest Equipment capable of
test voltages as listed in Table 4, the following equ ipment is
also req uired:
• AC Hig h Potential tester with test voltage of 1 500 volts,
60 Hz
•Test equipment for contact resistance tests.
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