Powell 38PV40ARMM-4, Instruction Bulletin

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27 Installation
01.4IB.65131
After the high potential is removed, an
electrical charge may be retained by the
vacuum interrupter. Failure to discharge this
residual electrostatic charge could result in an
electrical shock. All six primary disconnecting
devices of the circuit breaker and the metallic
mid band ring if present should be grounded
and remain grounded for at least one minute
to reduce this electrical charge before coming
into contact with the primary circuit.
!
WARNING
Remove all grounding conductors applied for
this test before placing the circuit breaker back
into service.
!
CAUTION
The tests described in this section are the
only tests required to ascertain insulation
integrity. Because of the design of the
PowlVac® insulation system, no valid data
can be obtained utilizing other types of
high voltage insulation tests.
2) Vacuum Integrity
Applying abnormally high voltage across
a pair of contacts in vacuum may produce
x-radiation. The radiation may increase with
increased voltage and/or decreased contact
spacing.
X-radiation produced during this test with
the voltage specified in Table A and normal
contact spacing is extremely low and well
below the maximum permitted by standards.
Do not apply voltage that is higher than the
recommended value. Do not use contact
separation that is less than the normal open
position separation of the circuit breaker
contacts.
!
CAUTION
Powell recommends AC testing for reliable
verification of vacuum integrity. All
PowlVac 38™ ARM 3000A Series 4 vacuum
circuit breakers shall be tested with a
minimum of 40kVAC applied directly across
fully open contacts for 10 seconds. No
dielectric breakdown during the test period
constitutes a successful test.
Note
: This test does not replace the AC
high potential testing (Hipot) used to
determine “High voltage insulation
integrity.” See Ch 4 Installation,
D. Placing Circuit Breaker Into Service,
1) High Voltage Insulation Integrity .
Powell offers a compact and lightweight
PowlVac ® Vacuum Integrity Tester
designed specifically for PowlVac circuit
breakers. If this device is used refer to
the instruction bulletin provided with the
vacuum integrity tester.