GE IAC51V Instructions Manual page 16

Time
GEH-1753
Overcurrent
INTRODUCTION
The a-c tripping unit is a Type
designed to energize a circuit breaker trip coil from
its associated current transformer upon the operation
of the main unit of the lAC relay.
current from the secondary of the current trans­
former into the trip coil and removes the current
from the trip coil when the breaker trips.
The tripping unit is mounted on the rear of the
frame opposite the
(
induction unit see Fig.
unit is illustrated in Fig.
circulates through the induction unit current coil
and the main coil of the
returning through the
transformer. Normally, most of the flux generated
REA
by the main coil passes through the upper limb
of the magnetic structure and holds the armature
unit
firmly against this limb.
induction close, the shorting coil of the
a t
short-circuited and current
transformer c ion, causing a redistribution of flux
REA
which actuates the armature and the
The opening of the
current to flow through the tri
breaker.
0.0 . )0
0.025
.
�
o.c;2o
w.J
{).01�
a.. ....
::l
�
0
0.010
0.005
0
0
Fig.
8
Relays Type
lAC
A·C TRIPPING
REA
relay unit
It transfers the
tapped operating coil of the
8). The operation of this
9.
The se condary current
REA
auxiliary tripping unit,
REA
contacts to the current
When the contacts of the
REA
flows in this coil by
REA
contacts.
p
contacts causes the secondary
coil which trips the
)
1 2
t.t.IL T I PLES
10 (6306872 [5])
Tl.me-current Characteristics
UN11
CURRENT
TRANS
is
9
of Type
Fig. (K-6154766-2)
lAC Relays having an
OPERATING TIME
RANGE
FOR Nff
SffiiNG
PICKUP
4 6 7
OF' PI CK-uP
of
Original Instantaneous Unit
COIL
T&SI
BREAKER
TRIP
TlltP UNIT
SHOI!T I loG
AC
COIL
AC TRII' UNIT
'MAIN CO'IL
Operatio�
A-C
Diagram Illustrating
Tripping Unit.
b 10