Vacuum Integrity Test Procedure; As-Found Insulation And Contact Resistance Tests; Insulation And Contact Resistance Test Equipment - Siemens 3AH Instructions, Installation, Operation, Maintenance

Maintenance
Figure 16. 3AH Pole Assembly / Vacuum Check Mechanical / Contact Resistance Test
Note: Do not use DC high potential testers
incorporating half-wave rectification. These devices
produce high peak voltages.
These high voltages will produce X-ray radiation.
These devices also show erroneous readings of leak-
age current when testing vacuum circuit breakers.

Vacuum Integrity Test Procedure

1. Observe safety precautions listed in the danger and
warning advisories. Construct the proper barrier and
warning light system.
2. Ground each pole not under test.
3. Apply test voltage across each pole for one minute.
(Breaker open).
4. If the pole sustains the test voltage for that period, its
vacuum integrity has been verified.
Note: This test includes not only the vacuum interrupter,
but also the other insulation components in parallel with
the interrupter. These include the standoff insulators and
the insulated drive links, as well as the insulating (tension)
struts between the upper and lower vacuum interrupter
supports. If these insulation components are contaminated
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 breaker insula-
tion system. Megger or insulation resistance tests con-
ducted 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 organi-
zation to determine when corrective actions are required
by watching for significant deterioration in insulation re-
sistance, or increases in contact resistance.

Insulation and Contact Resistance Test Equipment

In addition to the High Potential Test Equipment capable
of test voltages as listed in Table 4, the following equip-
ment is also required:
• AC High Potential tester with test voltage of 1500 volts,
60 Hz
• Test equipment for contact resistance tests.
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