T Y P E CO CIRCUIT OP E NING RE LAY
INDICATING INSTANTANEOUS TRIP
The core screw must be adj usted to the value of
Plck-up current desired.
The nameplate data will furnish the actual cur
rent range that may be obtained from the liT unit .
I NSTAL LATION
The relays s hould be mounted on s witchboard
panels or their equivalent in a location free from dirt ,
moisture, exce ssive vibration and heat.
Mount the
relay vertically by means of the mounting stud for the
type I<,T projection case or by means of the four
mounting holes on the flange for the semi-flush type
FT case. Either the stud or the mounting screws may
be utilized for grounding the relay. The electrical
connections may be made directly to the terminals by
means of screws for steel panel mounting or to the
terminal stud furnished with the relay for thick p anel
mounting. The terminal stud may be e asily removed
or inserted by locking two nuts on the stud and then
turning the proper nut with a wrench.
For detail information on the FT case refer to
IL
4 1-076.
ADJUSTMENTS AND MAI NTE NANC E
The proper adjustments to insure correct opera
tion of t his relay have been made at the factory. Upon
receipt of the relay no c ustomer adjustments , other
than those covered under " SETTINGS" should be
required.
ACC EPTANCE CHECK
The following check is recommended to insure
that the relay is in proper working order:
1.
CONTACTS
a) By turning the time dial , mov e the moving con
tacts until they d eflect the stationary cont act
to a po sition where the stationary contact is
resting against its backstop . The index mark
located on the movement frame should coincide
with the
"0"
mark on t he time dial.
b) For relays identified with a "T" , located at
lower l eft of stationary contact block, the index
mark on the m ovement frame wi ll coincide with
the
' ' 0 ' '
mark on the time dial when the station
ary contact has mov ed through approximately
1 4
one-half of its normal deflection. Therefore,
with the stationary contact resting against the
backstop , the index mark is offset to the r ight of
the
" 0 "
mark by approximately
.
0
2
0
" .
The
placement of the various time dial po sitions in
line with the index mark will give op erating
times as shown on the respective time-current
curves.
For typ e
C0- 1 1
relay only, the
1 . 30
times tap
valu e operating time from the number 6 time di al
po sitio n is 54.9
±
5% seconds and should be check
ed first. It is important that the
1 . 30
times tap value
current be maintained accurately. Th e maintaining
of thi s current accurately i s necessary because of
the steepness of the slope of the time-current char
acteristic (Figure 9 ) . A 1% variation in the
1 . 30
times tap value current ( including measuring in stru
ment deviation) will change the nominal operating
time by approximately 4%.
2.
MINIMUM TRIP CURRENT
Set the time dial to position
6.
Alternately apply
tap value current plus
3%
and tap value current minus
3%. The moving contact s ho uld leave the backstop
at tap value current plus
3%
and should return to the
backstop at tap value c urrent minus
3%.
3.
TIME CURVE
Table I shows the time curve calibration points
for the various types of relays. With the time dial set
to the indicated position, apply t he currents speci
fied by Table I, ( e . g . for the
co- 2,
3 and
20
time s
tap value current) and measure the operating time of
the relay. The operating times should equal those of
Table I plus or minus 5 percent.
4.
DE-ION CONTACTOR SWITCH
The de-ion contactor switch should operate with
a minimum of
4
amperes a-c applied.
5. OPERATION INDICATOR
The operation indicator should operate with a
minimum of 3 amperes a-c applied.
The operation
indicator target should drop freely.
6 .
INDICATING INSTANTANEOUS TRIP UNIT (liT)
The core screw which is adjustable from the top
of the trip unit determines the pickup value. The trip
unit has a nominal ratio of adjustment of
1
to
4
and
an accuracy within the limits of
1 0% .
The making of the contacts and target indication
should occur at approximately the same instant. The
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