TYPES I RP, I R C AND I R D R E LAYS
Time Overcurrent Unit
Range
Taps
. 5- 2 . 5
0 . 5
0 . 6
0 . 8
1 . 0
1 . 5
2.0
2. 5
2-6
2
2. 5
3
3 . 5
4
5
6
4- 1 2
4
5
6
7
8
10
1 2
The tap value i s the minimum current required to
just close the relay contacts.
The time vs. current characteristics for the time
overcurrent unit are shown in Figs.
10
to
16.
Thes e
characteristics give the contact closing time for the
various time dial settings when the indicated multi
ples of tap value current are applied to the relay.
T rip Ci rcui t
The relay contacts will safely close
30
amperes
at 250 volts
d
c and the seal-in conlacts of the indi
c:lting contactor switches will safely carry this cur
rent long enough to tri p a circuit breaker.
The indicating contactor switch has two taps that
provide a pickup setting of
0 . 2
or
2
amperes . To
change taps requires connecting the lead located in
front of the tap block to the desired setting by means
of a screw connection.
TIIP
WITN
RELATIVE
IIIIAIITAIIEOUS
POlAI ITY
AS
SIKMI, TilE O I IECTIOIAL
UII IT COMTACT CLOSES TO TilE LEFT.
IUTAIITAIEOU$
O'IEIC&IUEMT
Wi l T
(UH'EI
CYLIIKI
!M I T )
UTUIATIIIQ
TIAISFOIMll
lED
DOT
DIIECTIOIAL
!*IT
( LOIIIEI
CYLI IIIEI
UIIIT)
IUUCTI.
UIIT
CMASSIS
Of"£1AJED
SMOI:TIIQ
SIITCM
lED IIAULE
TEST s-.TCM
CUII£1T TEST .uti
T
UMU
I
A
L
184A034
F ig.
B.
Internal Schematic of the Type /RC Relay in the
Type F T 3 l Case.
6
C o n ta cts
The moving contact assembly has been factory
adjusted for low contact bounce performance and
should not be changed.
The set screw in e ach stationary contact has
been shop adjusted for optimum follow and this ad
justment should not be disturbed.
WITH RELATIVE IIISTAIHANEOUS
POLAR ITY AS SIIOWII, THE D I RECT I ONAL
U II J T CONTACT CLOSES TO TilE LEFT.
INSTAIITANEOUS
OVERCURRENT UIII I T
(UPPEII CYLINDEII
UNIT)
S.UURA.TIMQ
TRAIISFOR,.ER
liED DOT
III.DUCTION UIIIT
O I IIECTIOIIAL UIIIT
(LOWER CYLI IIDER
UNIT)
CHAS S I S OPERATED
StiORTING SWITCH
REO HANDLE
SWITCH
TERMIIIAL
184Ao33
F ig.
7.
Internal Schematic
of
the Type IRP Relay in the
Type F T3 l Case.
DIRECTIOIAL.
COliTACTS
( N O DDLE U I I T )
WITit RELATIVE
I II STAIITAIIEOUS
I"OLAR ITY AS SHOWII,
THE DIII:ECTIOUl
UIIIT
COIITACT
CLOSES TO TME lEFT.
184A020
F ig.
9.
Internal Schematic
of
the Type IRD Relay in the
T _-,., t- F T4 1 Case.
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