Eaton W-VAC Series Instructions For Installation, Operation And Maintenance page 45

No./Section Inspection Item
4. Operating Dust or Foreign Matter
Mechanism
Lubrication
Deformation or
Excessive Wear
Manual Operation
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 RECOM-
MENDED VOLTAGE AND NORMAL CONTACT
SPACING IS EXTREMELY LOW AND WELL BELOW
MAXIMUM PERMITTED BY STANDARDS. HOWEV-
ER, AS A PRECAUTIONARY MEASURE AGAINST
POSSIBILITY OF APPLICATION OF HIGHER THAN
RECOMMENDED VOLTAGE AND/OR BELOW NOR-
MAL CONTACT SPACING, IT IS RECOMMENDED
THAT ALL OPERATING PERSONNEL STAND AT
LEAST ONE METER AWAY IN FRONT OF THE
BREAKER.
With the breaker open and securely sitting on the floor,
connect all top primary studs (bars) together and the
high potential machine lead. Connect all bottom studs
together and ground them along with the breaker frame.
Start the machine at zero potential, increase to appropri-
ate test voltage and maintain for one minute.
Successful withstand indicates that all interrupters have
satisfactory vacuum level. If there is a breakdown, the
defective interrupter or interrupters should be identified
by an individual test and replaced before placing the
breaker in service.
AFTER THE HIGH POTENTIAL IS REMOVED, AN
ELECTRICAL CHARGE MAY BE RETAINED BY THE
VACUUM INTERRUPTERS. FAILURE TO DIS-
CHARGE THIS RESIDUAL ELECTROSTATIC
IB131009EN
Criteria
No dust or foreign
matter
Smooth operation
and no excessive
wear
No excessive
deformation or wear
Smooth operation
WARNING
WARNING
Inspection Method
Visual Check
Sight and feel
Visual and operational
Manual charging closing
and tripping
CHARGE COULD RESULT IN AN ELECTRICAL
SHOCK. ALL SIX PRIMARY TERMINALS AND THE
CENTER RING OF EACH VACUUM INTERRUPTER
OF THE CIRCUIT BREAKER SHOULD BE GROUND-
ED TO REDUCE THIS ELECTRICAL CHARGE
BEFORE COMING IN CONTACT WITH THE PRIMA-
RY CIRCUIT.
To avoid any ambiguity in the ac high potential test due
to leakage or displacement (capacitive) current, the test
unit should have sufficient volt-ampere capacity. It is
recommended that the equipment be capable of deliver-
ing 25 milliamperes for one minute.
Although an ac high potential test is recommended, a dc
test may be performed if only a dc test unit is available.
In this case the equipment must be capable of delivering
5 milliamperes for one minute to avoid ambiguity due to
field emission or leakage currents and the test voltage
shall be as shown in Table 6.1.
The current delivery capability of 25 ma ac and 5 ma dc
apply when all three VIs are tested in parallel. If individ-
ual VIs are tested, current capability may be one third of
these values.
Table 6.1 Test Voltage
Breaker Rated
Maximum Voltage
Up to and including
17.5 kV
Instruction Book
Page 39
Corrective Action
Clean as necessary
Lubricate very sparingly
with light machine oil
Remove cause and replace
parts
Correct per trouble-shooting
chart if necessary
Vacuum Interrupter Integrity Test Voltage
ac 60 Hz dc
27 kV 40 kV