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INTRODUCTION
The instantaneous unit is a small instantaneous
hinge-type unit which may be mounted on the right
front side
of
the induction
contacts are normally
the contacts of the main unit.
in series with the operating coil of the main unit.
When the current reaches a predetermined value,
the instantaneous unit operates, closing the contact
rircuit and raising its target into view.
latches
in
the exposed position until released by
pressing
the
button beneath the lower left-hand
corner of the relay cover.
APPLICATION
The instantaneous unit is used on certain lAC
relay models to provide instantaneous tripping for
current exceeding a predetermined value.
OPERATING
CHARACTERISTICS
The instantaneous element operates over a
1
range and has its calibration stamped on a scale
Fig. 7.
(8006998)
Type
Instantaneous Unit.
INSTANTANEOUS UNIT
7).
unit (See Fig.
connected
in parallel with
Its coil is connected
The target
OP[IIATING
COIL
CONTACTS
CONTACT
ASSEMBLY
lAC Relay with an
Time Overcurrent Relays Type lAC
mounted beside the adjustable pole piece.
current
characteristics
Its
The instantaneous unit is designed to use either
of two coils having pickup ranges of
20
80
to
amperes respectively.
rating of the contacts is
250
not exceeding
Burden data on the instantaneous unit coils are
given in the following table:
Coil
Freq.
10-40
60
50
25
20-80
60
50
4
to
25
Fig. 8.
(8007060)
A-C Tripping Unit.
are
shown
in
RATINGS
10
The current-closing
30
amperes for voltages
volts.
BURDENS
Volt
Imp.
Amp.
Amp
Ohms
5
0.83
0.033
5
0.80
0.032
5
0.65
0.027
5
0.21
0.008
5
0.20
0.008
5
0.15
0.007
Type
IAC Relay with an
GEH-1753
Time
10.
Fig.
to
40,
and
PF
0.95
0.95
0.98
0.95
0.95
0.98
7
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