Eaton 50 VCP-TR16, Инструкция по использованию

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Instruction Book
Effective: November 2017 Page 52
For more information visit: www.Eaton.com IB131016EN
WARNING
APPLYING ABNORMALLY HIGH VOLTAGE
ACROSS A PAIR OF OPEN 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 WELL BELOW MAXIMUM PERMITTED
BY STANDARDS. HOWEVER, AS A
PRECAUTIONARY MEASURE AGAINST
POSSIBILITY OF APPLICATION OF HIGHER THAN
RECOMMENDED VOLTAGE AND/OR BELOW
NORMAL CONTACT SPACING, IT IS
RECOMMENDED THAT ALL OPERATING
PERSONNEL STAND AT LEAST ONE METER
AWAY IN FRONT OF THE BREAKER.
With the circuit breaker open and securely sitting on the
floor or secured in a fixed position, connect all top
primary studs (bars) together and to 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 appropriate 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
circuit breaker in service.
WARNING
AFTER THE HIGH POTENTIAL IS REMOVED, AN
ELECTRICAL CHARGE MAY BE RETAINED BY THE
VACUUM INTERRUPTERS. FAILURE TO
DISCHARGE THIS RESIDUAL ELECTROSTATIC
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
GROUNDED TO REDUCE THIS ELECTRICAL
CHARGE BEFORE COMING IN CONTACT WITH
THE PRIMARY 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
delivering 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 6.2.
Table 6.2 Test Voltage
Breaker Rated
Maximum Voltage
Vacuum Interrupter Integrity Test Voltage
at 60 Hz dc
4.76 kV
20 kV 28 kV
8.25 kV 20 kV 28 kV
15.0 kV 27 kV 40 kV
The current delivery capability of 25 ma ac and 5 ma dc
apply when all three VIs are tested in parallel. If
individual VIs are tested, current capability may be one
third of these values.
WARNING
SOME DC HIGH POTENTIAL UNITS, OPERATING
AS UNFILTERED HALF-WAVE RECTIFIERS, ARE
NOT SUITABLE FOR USE TO TEST VACUUM
INTERRUPTERS BECAUSE THE PEAK VOLTAGE
APPEARING ACROSS THE INTERRUPTERS CAN
BE SUBSTANTIALLY GREATER THAN THE VALUE
READ ON THE METER.
6-4 CONTACT EROSION (Up TO 25KA)
Since the contacts are contained inside the interrupter,
they remain clean and require no maintenance.
However, during high current interruptions there may be
a minimum amount of erosion from the contact
surfaces. Maximum permitted erosion is 3 mm. To
determine contact erosion, close the breaker and
observe the vacuum interrupter moving stem from the
rear of the breaker. If the mark on each stem is visible,
erosion has not reached maximum value thus
indicating satisfactory contact surface of the interrupter.
If the mark is not visible, the pole unit assembly must
be replaced (Figure
6-1).
6-5 CONTACT WIPE (Up TO 25KA)
To check contact wipe, close the breaker and observe
the drive insulators from the rear of the breaker (Figure
6-2). Since the indicator to be observed is in the lower
rear portion of each pole unit assembly, a flashlight
should be used. Refer to Figures
6-3 and 6-4 for
graphical representations of satisfactory and
unsatisfactory contact wipe conditions. If the identified
wipe indicator is observed to be below the top surface
of the drive insulator as shown in Figure
6-3, the contact
wipe is satisfactory. If the wipe indicator is observed to
be flush with or protruding out past the top surface of
the drive insulator as shown in Figure
6-4, the contact
wipe is unsatisfactory. The pole unit assembly must be
replaced when an unsatisfactory wipe condition is
observed.