Inspection; Frequency Of Inspection; Inspection Process; Vacuum Interrupter Integrity Test - Eaton W-VACi User Manual

4 Inspection

4.1 Inspection
 Do not work on a breaker in the "service"
position.
 Do not work on a breaker with secondary
disconnects engaged.
 Do not work on a breaker with springs
charged or contacts closed.
 Do not override any safety interlocks.
 Do not leave the manual charging handle in
working location after charging the closing
springs.
 Do not stand less than one meter away from
the breaker when testing for vacuum integrity.
4.2

Frequency of Inspection

It is recommended to inspect the breaker when it is
received. In cases where the breaker operates in a
clean and non-corrosive environment, the circuit
breaker should be inspected after 10 years or 10,000
operations, whichever comes first. In dusty and/or
corrosive environment, inspection should be performed
at least once a year. Additionally, it is recommended to
inspect the breaker every time it interrupts a fault
current.
4.3

Inspection Process

See Table 4-4 and follow the steps to inspect the
breaker.
4.4 Vacuum Interrupter Integrity
Test
Vacuum interrupters used in all W-VACi circuit
breakers are highly reliable interrupting elements.
Satisfactory performance of these devices is
dependent upon the integrity of the vacuum in the
interrupter and the internal dielectric strength. Both of
these parameters can be readily checked by a one
minute AC high potential test. During this test, the
following warning must be observed:
Table 4-1: Testing Ratings
Breaker
12kV
17.5kV
24kV
This test should be done with the breaker in "OPEN"
position.
40
WARNING
Testing Voltage
28kV ac
38kV ac
50kV ac
65A7355H01 November 2011 www.eaton.com
Applying abnormally high voltage across a pair
of contacts in vacuum may produce x-radiation.
The radiation may increase with the increase in
voltage and/or decrease in contact spacing. X-
radiation produced during this test with
recommended voltage and normal contact
spacing is extremely low and is well below
maximum levels.
After the high potential test is conducted, an
electrical charge may be retained by the vacuum
interrupters. Failure to discharge this residual
electrostatic charge could result in an electrical
shock. Follow safety procedures for this type of
test.
4.5

Insulation Inspection

Insulation inspection is performed to keep all insulating
surfaces clean. This can be done by wiping all
insulating surfaces with a dry lint free cloth and
denatured alcohol. In case there is any tightly adhering
dirt that will not come off by wiping, it can be removed
with a mild solvent or distilled water. Confirm that the
surfaces are dry before placing the breaker in service.
If a solvent is required to remove the dirt, once the
switchgear has been isolated, use benzene or white
spirit. Secondary control wiring requires inspection for
tightness of all connections and damage to insulation.
WARNING
WARNING