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I.L. 41-103H
I NTUUL SCHENA Tl C
OPEUTIQII UIOICATOR
AUX. CUUEJIT
TRAIISF. SECOIDUY
�
TEST SWITCH
--
FROII T YIEW
2
NOTE: i£RM.
AJIO 8 ARf TO 8[
JUMPERED AT RELAY CASE
Fig. 1.
Internal Schematic of the Circuit Opening Type
CO Relay in Type F T-21 Case
OPERATION INDICATOR (OI)
The operation indicator is a small clapper type
device. A magnetic armature is attracted to the
magnetic core upon energization of the switch.
When the switch closes two fingers on the arma
ture deflect a spring located on the front of the
switch,
which
allows the operation indicator
target to drop.
The front spring, in addition to holding the
target, provides restraint for the armature and
thus controls the pickup value of the switch.
INDICATING INSTANTANEOUS
TRIP UNIT (liT)
The instantaneous trip unit is a small a-c oper
ated clapper type device. A magnetic armature, to
which leaf-spring mounted contacts are attached,
is attracted to the magnetic core upon energiza
tion of the switch. When the switch closes, the
moving contacts bridge two stationary contacts
completing the trip circuit. Also, during the op
eration, two fingers on the armature deflect a
spring located on the front of the switch which
allows the operation indicator target to drop.
A core screw accessible from the top of the
switch provides the adjustable pickup range.
2
---- -- -- -- --
OE·IOII
CONTACTOR SWITCH
AUX. CURRENT
TUIISF. f'IIMAU
cs
co
IIIOUCTtON UNIT
C K A S S I S OPEIATtO
SHOITIII!I SWITCH
TE-.IUL
Sub2
183A055
INTERNAL SCHENAT IC
OPEUTIOII IIIOICATOR
AUX. CURII:EIIT
TilUSF. SECOJIDARY
TEST Sifii i TCH
Fig. 2.
Internal Schematic of the Circuit Opening Type
CO Relay, with Indicating Instantaneous Trip,
in Type F T-21 Case
CHARACTERISTICS
The relays are available in the following current
range:
RANGE
4- 12
4
5
12
The circuit-opening relay is recommended only
in the 4 to
ampere range. A lower range is
not desirable because the burden of a low-range
trip coil is too heavy on the current transformer.
One trip coil is required for each relay.
5.7
The burden of the auxiliary current trans
former at 4 amps. is 4. 6 VA with contacts
CO closed and
VA with contacts open.
3
The time vs. current characteristics are shown
in Figs.
to 9. These characteristics give the con
tact closing time for the various time dial settings
when the indicated multiples of tap value current
are applied to the relay.
DE-ION
COHTACTOR SWITCH
AUX. CURREIH
TRAMSF. PRht.
IMOICATIII<i
INSTANTAiiEOUS
TRIP UN IT
!IIDUCTIOII UMIT
CHASSIS OPERATED
SHOII:TIMG SlitiTCH
C UIIREIIT TEST JACK
TAPS
7
8
6
10
12
liT
or
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