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FP-25-LV-VSR
Breaker-To-Motor Starter Conversion
6.3.5 Inspection After Short Circuit
The magnitude of a short circuit may exceed the damage threshold
of the vacuum bottle on the V201 contactor. After a short circuit,
the unit should be examined for any apparent physical damage,
or deformation of the conductor bars. If there is any evidence of
severe stress, it is recommended that the unit be replaced. If the
over-travel has changed significantly (from the last inspection) on one
or more bottles, the unit should be replaced.
A dielectric test may be performed at 1760 Vac (80% of factory test
level) (see Section 6.6). A dielectric test would not by itself confirm
that the unit should be returned to service after a fault. Vacuum
Integrity is to be performed at 5.5 kVac RMS per Section 6.4.
However, if there is no physical evidence of stress, and if the over-
travel exceeds the 0.020 in. (0.51 mm) minimum, the bottles can
then be dielectrically tested as outlined in this manual. If physical
stress, over-travel, and dielectric are satisfactory, it is reasonable
to return the unit to service after a fault and after unit has been
properly cleaned.
6.4 Vacuum Interrupter Integrity Test
Vacuum interrupters used in the LV-VSR are highly reliable
interrupting contactors. 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.
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 THE MAXIMUM PERMITTED BY
STANDARDS. HOWEVER, AS A PRECAUTIONARY MEASURE AGAINST THE
POSSIBILITY OF APPLICATION OF HIGHER THAN RECOMMENDED VOLTAGE
AND/OR BELOW NORMAL CONTACT SPACING, IT IS RECOMMENDED THAT
ALL OPERATING PERSONNEL STAND AT LEAST 3.2 FEET (1 METER) AWAY
IN FRONT OF THE LV-VSR.
Only use an AC high potential test set. A DC high potential test may
result in inaccurate test results.
1. Conduct the test with the LV-VSR open and securely placed on a
workbench or suitable surface.
2. Short the CTs and the secondary block connections to ground.
3. Connect all top primary studs (bars) together and the high
potential machine lead.
4. Connect all bottom studs together. Do not ground them to the
LV-VSR frame. Connect the high potential ground to the bottom
studs.
5. Start the machine at zero potential, then increase to 5.5 kV AC
RMS and maintain for one minute.
6. Successful withstand indicates that all interrupters have
satisfactory vacuum levels. If there is a breakdown, the contactor
should be replaced before placing the LV-VSR in service.
7 . After the high potential is removed, discharge any electrical
charge that may be retained, particularly 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.
8. Remove ALL shorting wire on CTs and secondary block before
placing unit back into service.
20
Instruction Book
IB019008EN October 2016 www.eaton.com
WARNING
FAILURE TO REMOVE ALL SHORTING WIRE FROM THE CURRENT
TRANSFORMERS AND SECONDARY CONNECTIONS MAY CAUSE INJURIES
AND EQUIPMENT DAMAGE.
DC HIGH POTENTIAL TESTS ARE NOT RECOMMENDED ON VACUUM
INTERRUPTER ASSEMBLIES.
6.5 Insulation
In LV-VSRs, insulation maintenance primarily consists of keeping
all insulating surfaces clean. This can be done by wiping off all
insulating surfaces with a dry lint free cloth. 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. Be sure that the
surfaces are dry before placing the LV-VSR in service. If a solvent is
required to cut dirt, use isopropyl alcohol. Secondary control wiring
requires inspection for tightness of all connections and damage to
insulation.
6.6 Insulation Integrity Check
Primary Circuit
The integrity of primary insulation may be checked by the AC high
potential test. The test voltage is 1760 V RMS, 60 Hz. Conduct the
test as follows.
1. Conduct the test with the LV-VSR open and securely placed on a
workbench or suitable surface.
2. Ground the LV-VSR frame.
3. Short the CTs connections to ground.
4. Close the contactor on the LV-VSR. Control power will be
needed to close the Contactor.
5. Connect the high potential lead of the test machine to one of the
phases of the LV-VSR.
6. Connect the remaining two phases and LV-VSR frame to ground.
7 . Start the test machine with the output potential at zero and
increase to the test voltage. Maintain the test voltage for one
minute.
8. Repeat for the remaining phases. Successful withstand indicates
satisfactory insulation strength of the primary circuit.
9. Disconnect the control power from the LV-VSR.
10. After the control power has been removed and disconnected
from the LV-VSR, short all of the secondary connections together
and to the frame.
11. Connect the high potential lead of the test machine to one of the
poles of the LV-VSR.
12. Connect the remaining poles and LV-VSR frame to ground.
13. Start the test machine with the output potential at zero and
increase to the test voltage. Maintain the test voltage for one
minute.
14. Repeat for the remaining poles. Successful withstand indicates
satisfactory insulation strength of the primary circuit.
15. Remove ALL shorting wire on the CTs and secondary block
before placing unit back in to service.
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