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T Y P E CO C I R C U I T O P E N I NG R E LAY
INDICATING INSTANTANEOUS TRIP (liT
The core screw must be adj usted to the value of
Plck-up current desired.
The nameplate data will furnish the actual c ur
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.
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.
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 i nformation o n the FT case refer to
IL
4 1-0 76.
ADJUSTMENTS AND MAI N T E 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:
CONTACTS
1.
a) By turning the time dial , mov e the moving con
tacts until they d eflect the stationary cont act
to a p o 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 h as mov ed through approximately
1 4
one-half of its normal deflection. Therefor e ,
with the stationary contact resting against the
backstop , the index mark i s offset to the r ight of
the
placement of the various time dial po sitions in
line with the i ndex 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 tim e s tap
valu e o p erating tim e from the number 6 time di al
po sitio n i s 5 4 . 9
Mount the
ed first. It is important that the 1 . 30 times tap value
current be m aintained accurately. Th e maintai ning
of thi s current accurately i s necessary becau s e of
the steepness of the slo p e of the time-current char
acteristic (Figu re 9 ) . A 1% variation in the 1 . 30
The electrical
times tap value current ( including m easuring in stru
m ent deviation) will change the nominal operating
time by approximately 4%.
MINIMUM TRIP CURRENT
2.
Set the time dial to position
tap value current plus 3% and tap value c urrent minus
3%.
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 s e t
t o the indicated position, apply t he currents speci
fied by Table I, ( e . g . for the
tap value current) and measure the operating time of
the relay.
Table I plus or minus 5 percent.
DE-ION CONTACTOR SWITCH (CS)
4.
The de-ion contactor switch should operate with
a minimum of
5. OPERAT ION INDICAT OR (OI)
The
minimum of 3 amperes a-c applied.
indicator target should drop freely.
INDICATING INSTANTANEOUS TRIP UNIT (liT)
6 .
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
an accuracy within the limits of
The making of the contacts and target indication
should occur at approximately the same instant. The
" 0 "
mark by approximately
±
5% seconds and should be check
The moving contact s ho uld leave the backstop
co- 2 ,
The operating times should equal those of
amperes a-c applied.
4
operation indicator should operate with a
0 2 0
The
.
" .
Alternately apply
6.
time s
3 and
20
The operation
to
and
1
4
1 0% .
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