Powell 38PV40ARMM-4, Instruction Bulletin

Page: 60 / 68

Powered by Safety
®
50 Maintenance
PowlVac 38™ ARM 3000A Series 4
Vacuum Circuit Breaker
01.4IB.65131
6. Turn the close bar adjusting screw
3 to 3½ turns counterclockwise.
Retighten the locking nut holding
the screw.
7. Repeat step 5 . Then CLOSE and
OPEN the circuit breaker to ensure
proper operation.
8. Replace the escutcheon .
6) Electrical Operation
After performing any necessary mechanical
and lubrication maintenance, operate the
circuit breaker electrically several times to
ensure that the electrical control system
works properly. See Ch 4 Installation,
D. Placing the Circuit Breaker Into Service,
5) Electrical Operation Check .
c. v
AcuuM
I
nterrupter AnD
c
ontAct
A
reA
1) Vacuum Interrupter and Contact Erosion
At each inspection the vacuum interrupters
should be checked for contact erosion.
The circuit breaker must be closed for this
check. Each new vacuum interrupter is set
with a gap of about 1/4” to 5/8” between
the contact loading spring yoke and the
lock nut on the operating pushrod stud. As
the contacts erode with use, this gap will
decrease. Because the factory setting of
the lock nut gap varies for each vacuum
interrupter, a label is provided on the
lower part of each vacuum interrupter.
The original factory setting of the gap and
the end-of-life measurement of this gap
is recorded on the label. When the gap
measurement reaches the end-of-life value
given on this label, the vacuum interrupter
should be replaced.
2) Vacuum Integrity
Refer to Ch 4 Installation, D. Placing Circuit
Breaker into Service, 2) Vacuum Integrity
for information on vacuum integrity and
testing of vacuum interrupters.
3) Mechanical Adjustment of Vacuum
Interrupters
There are no adjustments required
for routine maintenance of a vacuum
interrupter assembly. There are several
factory adjustments which will vary over
the operating life of the vacuum interrupter.
Adjustments of these settings is only
necessary when repair requires the removal
or replacement of the vacuum interrupter.
Do not adjust these settings unnecessarily as
damage to the circuit breaker may result.
!
CAUTION
When it is necessary to remove or replace
the vacuum interrupter it should only be
done by a qualified technician or a Powell
service technician. Contact Powell for
further assistance at 1.800.480.7273.