The current-closing rating of the contacts is
30
amperes for voltages not exceeding
250
volts.
The current-carrying ratings are affected by the
selection of the tap on the target and seal-in coil
as indicated in the following table:
DUAL RATED
0.2/2.0
0.6/2.0
0.2
2.0
0.6
2.0
Carry
30
amps for
( sec)
0.05
2.2
0.5
3.5
Carry
10
amps for
(sec)
0.45
20
5.0
30
Carry continuously
(amp)
0.37
2.3
1.2
2.6
Minimum operating
(amp)
0.2
2.0
0.6
2.0
Minimum dropout
(amp)
0.05
0.5
0.15
0.5
DC resistance
(ohms)
8.3
0.24
0.78
0.18
60
hertz impedance
(Oh':l!S)
50
0.65
6.2
0.65
50
hertz impedance
(ohms)
42
0.54
5.1
0.54
If
the tripping current exceeds
30
amperes, an
auxiliary relay should be used, the connections being
such that the tripping current does not pass through
the contacts or the target and seal-in coils of the
protective relay.
48
45
42
311
}6
.n
30
v
0
L
27
T
A
G
24
(
21
18
15
12
9
6
)
0
Time Overcurrent Relays Type
lAC
GEH-1753
BURDENS
Burdens for the standard coils are given in the
following table.
These are calculated burdens at
five amperes based on burden of minimum tap.
Volt-ampere burdens for the lowest tap on any
of the three coils can be determined for any value
of current, up to
20
times tap setting, from Fig.
3.
Coil
Freq.
Tap
Volt-
Imp.
PF
Amperes
Amps
Ohms
4-16
60
4.0
8.8
0.35
0.29
50
4.0
8.0
0.32
0.31
25
4.0
7.5
0.30
0.36
1.5-6.0
60
1.5
59.0
2.36
0.26
50
1.5
52.0
2.08
0.28
25
1.5
48.0
1.92
0.34
0.5-2.0
60
0.5
530.0
2 1.2
0.26
50
0.5
470.0
18.8
0.28
25
0.5
430.0
17.2
0.34
25
TAP
RANGE
.5-2.0
60
"'
50
"'
1
TAP
...
4-16
50ft,
AMPS.
0
4
6
8
10
l2
14
16
18
20
MULTIPLES OF
MINIMUM TAP SETTING
SATURATION CURVES AT VARIOUS FREQUENCIES
FOR
3
TAP RAKGES
OF
THE TYPE IAC�lA RELAY
LOWEST TAP USED IN ALL CASES
fig. J.
(K-6306891-1)
Saturation Curves for Lowest
Taps .,f the
Induction Unit
of
Type lAC Relays
with Inverse-time Charactcrislics.
5
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