Powell 27PV25ASD, Руководство пользователя

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PowlVac® ASD 27kV & 38kV Vacuum Circuit Breaker
IB-65100
Installation
Recording the leakage readings is not
necessary, as a dielectric breakdown will
trip all portable DC hipot test sets. If a
DC test breakdown occurs, the test must
be repeated after reversing the DC high
voltage test supply connection across the
vacuum interrupter. The working condition
of a vacuum interrupter should be
questioned only if it has failed both tests.
CAUTION CAUTION !
When testing with DC, use a DC high
potential test (HIPOT) set with FULL WAVE
rectification. Do NOT use half-wave
rectifiers. The capacitance of the vacuum
interrupter in combination with the leakage
currents in the rectifiers and its DC voltage
measuring equipment may result in applying
peak voltages as much as three times the
measured voltage. These abnormally high
voltages may give a false indication of a
defective vacuum interrupter, and may
produce abnormal x-radiation.
CAUTION CAUTION
!
If DC high potential testing is performed,
the DC high potential test machine must
not produce instantaneous peak voltages
exceeding 57kV.
No attempt should be made to try to
compare the condition of one vacuum
interrupter with another, nor to correlate
the condition of any vacuum interrupter
with low values of DC leakage current.
There is no significant correlation.
3) Control Voltage Insulation Integrity
If the user wishes to check the insulation
integrity of the control circuit, it may be
done with a 500V or 1000V insulation
resistance tester or with an AC high
potential tester. The AC high potential test
should be made at 1125V, 50Hz or 60Hz for
one minute. The charging motor must be
disconnected prior to testing the control
circuit. The charging motor itself may be
similarly tested at a voltage not to exceed
675V, 50Hz or 60 Hz. Be sure to remove any
test jumpers and reconnect the charging
motor after the tests are complete.
CAUTION CAUTION !
Remove all grounding conductors applied for
field dielectric test before placing the circuit
breaker back into service.
4) Mechanical Operation Check
The mechanical operation of the circuit
breaker is checked by inserting the manual
charging handle into the manual charging
crank and pushing down until a metallic
click is heard. (The click indicates that the
holding pawl has dropped into place on the
ratchet wheel.) The procedure is repeated
until the spring charge indicator indicates
“Closing Spring Charged”. This requires
about 60 operations of the handle. Remove
the handle.