GE IAC51A Instructions Manual page 5

Time Overcurrent Relays Type lAC GEH-1753
The current-closing ratlng of the contacts is
30 amperes for voltages not exceedlng 250 volts.
BURDENS
•
The current-carrying ratings are affected
by
the
selection of the
tap
on the target and seal-ln coll
as lndicated In the (ollowlng table:
Burdens for the standard colls are given In the
followlng table. These are calculated burdens at
five amperes based on burden of mlnimum tap.
•
•
...
..
...
•
•
FUNCTION
Amperes, AC or DC
2-Amp Tap 0.2 Amp Tap
Volt-ampere burdens for the lowest tap on any
of the three colls can be determlned for any value
of current, up
to
20 times tap settlng, from Fig. 3.
Operatlng Range 2-30 0.2-2
Coll
Freq. Tap
Amperes
Trlpplng
Duty
30 5
Carry Contlnuously 3 0.3
Resistance 0.13 7
Impedance @ 60 cycles
0.53 52
If the trIPping current exceeds 30 amperes, an
auxlliary relay should be used, the connections belng
such that the trlPplng current does not pass through
the contacts or the target and seal-ln colls of the
protective relay.
y
o
.8
••
30
/
/
l 27
T
•
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/ /
.
"
[
21
18
12
•
•
o
k
.,,/ /
-0
Y
if"
~:
,./ ,./
/
.,./
4-16
1.5-6.0
0.5-2.0
/
/
/
/
I
./
'i
/
'/
/.
/
/
,.-
. /
~
.,./
o
2 4
Ii
8 10 12 14 16 18 20
MULTIPLEs OF MINIMUM TAP SETtiNG
SATURATION CURVES AT VARIOUS FREQUENCIES
FOR, TAP HAMGES OF THE TYPE IAC51' RELAY
LOWEST TAP USED ,. ALL CASES
60 4.0
50 4.0
25 4.0
60 1.5
50 1.5
25 1.5
60
0.5
50 0.5
25 0.5
TAP
RANGE
.5-2.0
.0
~
••
~
2 ....
TAP
RANGE
60 ... 1.5-6.0
50... AMPS •
}
TAP
.~
... G,
25 ... 4-16
50 ... AMP!.
Volt-
Imp.
Amps Ohms
8.8
0.35
8.0
0.32
7.5
0.30
59.0 2.36
52.0 2.08
48.0 1.92
530.0
21.2
470.0 18.8
430.0 17.2
Fig. 3 Saturation Curves for Lowest Taps of the Induction Unit of Type lAC Relays
with Inverse-time Characteristics
PF
0.29
0.31
0.36
0.26
0.28
0.34
0.26
0.28
0.34
5
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