WARNING
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 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 CIRCUIT
BREAKER.
Vacuum Interrupter Integrity Test
otee:
N
Roll over each high potential test diagram configuration above to see the
correct lead connection to the equipment.
otee:
N
The secondary disconnect must be grounded during test.
Vacuum interrupters used in Type VR-Series 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, using the appropriate test voltage in the following
table.
Circuit breaker Rated Maximum
Voltage
Vacuum Interrupter Integrity
Test Voltage
ac 60Hz
Up to and including 15.0 kV
27 kV
WARNING
DC HI-POTENTIAL TESTS ARE NOT RECOMMENDED BY EATON. DO NOT APPLY
DC AT ANY LEVEL TO VR-SERIES POWER CIRCUIT BREAKERS.
With the circuit breaker open and securely sitting on the floor, connect
all top/front primary studs (bars) together and the high potential machine
lead. Connect all bottom/rear studs together. Do not ground them to
the circuit 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.
After the high potential unit is removed, discharge any electrical charge
that may be retained. This charge is particularly true from the center shield
of vacuum interrupters. 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.
The current delivery capability of 25 mA ac and 5 mA dc apply when
all three VI’s are tested in parallel. If individual VI’s are tested, current
capability may be one third of these values.
Vacuum Interrupter Integrity Testing Configuration
OS
Lead
C B A
G/R
Lead
OS
Lead
C B A
G/R
Lead
OS
Lead
C B A
G/R
Lead
OS
Lead
C B A
G/R
Lead
OS
Lead
C B A
G/R
Lead
OS
Lead
C B A
G/R
Lead
OS
Lead
C B A
G/R
Lead
OS
Lead
C B A
G/R
Lead
OS
Lead
C B A
G/R
Lead
OS
Lead
C B A
G/R
Lead
OS Lead
= Output Signal Lead
G/R Lead
= Ground / Return Lead
4
EATON
| Visual Instruction Booklet Essentials | DST-2-VR - 18WR Element | May 2017
