L E A D
G)
POSI TION
RATED O-C
R E S I STOR
L E A D
0
VOLTAGE
R ESISTANCE
2
48
300
3
1 25
2700
4
250
6500
NOTE
.
R E L AYS ARE SHIPPED
ON TH
E
125 VOLT TAP
184A316
Fig. 13. Selection of Proper Voltage Tap for Auxiliary
Switch (CS- 1) Operation.
receipt of the relay, no customer adjustments, other
than those covered under "SETTINGS", should be
required.
Acceptance C h e c k
The following check is recommended t o insure
that the relay is in proper working order;
Instantaneous Overcurrent Unit (I)
1. Contact
- The gap between the station
ary and moving contacts with the relay in the de
energized position should be approximately . 0 20".
2 .
Minimum Trip Current - The D contacts
should
be
blocked clos ed when checking the pick-up
of the o vercurrent unit.
The pick-up of the overcurrent unit can be check
ed by inserting the tap screw in the desired tap hole
and applying rated tap value current. The contact
should close within
±
5% of tap value current.
Directional Unit (D)
1.
Contact Gap - The gap between the station
ary contact anct moving contact with the relay in the
de-energized position should be approximately . 020".
2. Sensitivity - The directional unit should trip
with 1 . 2 volts and 4 amperes at its maximum to rque
angl e ( current leading the voltage by 30
°
)
for the
4 to 1 2 amp ere range relays and
1.
2 volts and 2
amperes for the 0 . 5 to 2 . 5 ampere and the 2 to
6
ampere range relays.
1 8
3. Spurious Torque Adjustments - There should
be no spurious closing torques when the operating
circuits are energized per Table 2 with the polarizing
circuit short circuited.
Time Overcurrent Unit ( CO)
1.
Contacts - The index mark on the movement
frame will coincide with the
"0"
mark on the time
dial when the stationary contact has moved through
approximately one-half of its normal deflection. There
fore, with the stationary contact resting against the
backstop , the index mark is offset to the right of the
"0"
mark by approximately . 0 20". The placement of
the various time dial positions in line with the index
mark will give operating times as shown on the re
spective time-current curves.
2. Minimum Trip Current - Set the time dial to
position
6
with the auxiliary switch (CS- 1) contacts
blocked closed, alternately apply tap value current
plus 3% and tap value current minus 3%. The moving
contact should leave the backstop at tap value cur
rent plus 3% and should return to the backstop at
tap value current minus 3o/o-
3. Time Curve - Tabl e
1
shows the time curve
c al ibration points for the various types of rel ays.
With the time dial set to the indicated position, apply
the currents specified by Table 1 ( e g. for the IRV- 2
3 and 20 times tap value current) And m easure the
operating time of the relay. The operating times
should equal those of Table
1
plus or minus 5 percent.
For type IRV- 1 1 rei ay only, the 1. 30 times tap
val ue operating time from the number
6
time dial
po sition is 54.9 ±5% seconds. It is important that the
1 . 30 tim es tap v alue current be m aintained accurate
l y� The m aintaining of this current accuratel y i s ne
cessary b ecau se of the steepness of the slope of the
tim e- current characteristic (Fig. 19) . A 1% variation
in the 1. 30 times tap v al u e current (including m ea
suring instrument deviation) will change the nominal
operating time by approximately 4%.
Indicating Contactor Switches (ICS/ 1) and (ICS/T)
A) Close the contacts of the CO and the direc
tional unit (D) and pass sufficient d. c. current through
the trip circuit to close the contacts of (ICS/T). This
value of current should not be greater than the parti
cular (ICS/T) tap setting being used. The operation
indicator target should drop freely, bringing the letter
"T" into view.
B) Close the contacts of the instantaneous over
current unit (I) and the directional unit (D). Pass suf-
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