Toshiba VK-6M32A Installation Operation & Maintenance page 42

filav.31,2012
9:2lAM
No
1530
D
)1
Page 4O
MAINTENANCE
VACUUM
CHECK PROCEDURE FOR:
10040
6M/P/o50
t0MlP/o5o
The
relationship between
the
diel€ctric
breakdown vohage and
lhe
vacuum internal
pr€slruro is
shown in Fig. 54.
Ptoc6dure:
Voltage
is
ro
be
applied between
the
i6rmlnah of thc vacuum int6rupt6r
Start
tt
zeto and increase voltag0 gradually
lf
ammeter
shows current
flow,
reduce
voltags to zero and again incraaee.
Bepeat steps
{2}
ancl (3) d
few
tlmBs.
lf
th6 curent
increE8es
with a
voltage
lncrass6, th€
intsffuptsr
is d6fectiv6,
ll
zerc,
$
ne0llglble
(le$e
than
0.5
A)
currenl is found
with
a voltage
increase,
rhe intenupter is good.
1)
2t
3)
4)
Ra.Irtion
Expocura Hezard.
X-
Criteria:
lEy5 may cause ifiness
or iniury.
Stary
at leaSt
'l
mster
13.3
ft)
away
fiom
clrcult
breaker
durim
fii8
taEt.
lTwiEn-q
Hazildou$
Yortase$
ere
pr*ent
drdng
dlelestrlc testing
which
can
rrsult in eavcre iniury or derth.
Only quallfiad
peEonnd
$hould conduct thi$ testing.
$et up:
1)
Test circuit:
Fig.
49
2)
Circuit Breaker:
Test
in
opsn
"tripped'
poshion
3)
Expocted Failuro Volrage Fange:
17-21
kVac
4l
Applisd Test Voltage (Vappl; 25 kVac
5)
Tirne of appligd
voltegs:1Ossc.
maximum.
OTE:
Apply
voltage
at a
rat6
of
approximately 2kV per second until
Vapp
is
reached. Decrease
at
the
s€me rat€.
1)
2t
Fig.
53
Typicrl
T6nt S6tup
g
o
6 rli
I
c
€
.l
t
_a
'o
E
-t
o
to€
EE
Eg
:E
E;
lc ci
TE
Fio.
tr
Vottege
Vs. lntemal Vacuum Pressure