GE IAC53A User manual

INSTRUCTIONS
GEH-1788L
TIME OVERCURRENT RELAYS
TYPES
IAC53A IAC53R
IAC53B IAC54A
IAC53C IAC54B
GENERALf) ELECTRIC

GEH-1788 Tvne IAC Time Overcurrent Relay
TOP PIVOT
TAP PLUG
TAP BLOCK
SEAL-IN
UNIT
HOLDING
--- TIME DltlL
COIL
SEAL-IN
DISK SHAFT
TARGET
MAIN
SEAL-IN ._-- MOVING
UNIT CONTACT
STATIONARY
CONTACT, MA:N
LEFT
STATIONARY
BRUSH
AND
SEAL-I N--
CONTACT
UNIT
ASSEMBLY
STATIONARY
CONTACT, MAGNET
RIGHT DISK
SEAL-IN
MOVING
CONTACT
ASSEMBLY
Fig. I
The Induction Unit for Type lAC Relays (Front View)
DISK
AND
SHAFT---
LOWER .'
JEWEL SCREwj
COIL
ANO
TAP
BLOCK
-
ASSEMBLY
Fig. 2 The Induction Unit for Type lAC Relays (Rear View)
-
Ltl
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C'-I
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TIME OVERCURRENT RELAYS
TYPE lAC
INTRODUCTION
Type
Contact Instan. A-C Trip
Induc. Outline
lnt.
Circuits Unit
IAC53A(-)A
One No
IAC53B(-~A
One Yes
IAr.53C(- A One No
JAC53R(-)A
One Yes
IAC54A~-~A
Two No
IAC54B - A
Two Yes
The Types IAC53 and IAC54 relays are time
overcurrent relays with a very-inverse time char-
acteristic. They are employed to protect against
overcurrent on single-phase and poly-phase circuits.
The various relays described in this instruction book
differ in the number of circuits they close, and if an
instantaneous unit and/or an a-c tripping unit is
included.
These relays consist of an induction unit or an
induction unit with an instantaneous unit which per-
Unit Unit
&P. D.
Conn.
No
One
Fig. 20
Fig. 12
No
One
Fig. 20
Fig. 13
Yes On~
Fie:. 20
Fig. 14
Yes
One
Fig. 20
Fig. 15
No
One Fig. 20
Fig. 16
No
One
'Fig. 20
Fig. 17
.-
mits instantaneous tripping for exteremely high cur-
rents, or an induction unit with an a-c tripping unit for
use where d-c power is unavailable or a-c tripping is
preferred. Since practically all Type IAC relays are
composed of various combinations of the above (that
is, the induction unit, the instantaneous unit and the
a -c tripping unit), they are, for convenience, describ-
ed separately in the following text. The above table
indicates the units comprising each type and also lists
the internal connections and outline and panel drilling
diagrams.
INDUCTION UNIT
INTRODUCTION APPLICATION
The induction unit is the basic unit in all Type
JAC relays. Figs. 1 and 2 show the induction unit
mounted in the cradle. These units are of the induc-
tion-disk construction type. The disk is actuated by a
current operating coil on a laminated U-magnet. The
disk shaft carries the moving contact which completes
the alarm or trip circuit when it touches the station-
ary contact or contacts. The disk shaft is restrained
by a spiral spring to give the proper contact-closing
current and its motion is retarded by a permanent
magnet acting on the disk to give the correct time
delay.
There is a seal-in unit mounted on the front to
the left of the shaft. This unit has its coil in series
and its contacts in parallel with the main contacts
such that when the main contacts -close the seal-in
unit picks up and seals in. When the seal-in unit
picks up, it raises a target into view which latches
up and remains exposed until released by pressing
a button beneath the lower left corner of the cover.
The induction unit is the main unit in all Type
JAC relays, supplying the very inverse time delay
characteristics of the relay and sounding an alarm or
tripping the breakers for overload currents which
cause it to close its contacts.
OPERATING CHARACTERISTICS
The induction unit may have one or two circuit-
closing contacts which close as the current increases
to the pick-up value as set on the tap block. The
time delay in closing the contacts is determined by
the setting of the time dial (Fig. 1). The time-cur-
rent characteristics are shown in Fig. 3.
RATINGS
The induction unit is designed to use anyone of
four operating coilS, each having a different com-
bination of taps as follows, 4,5,6,7,8,10,12, and 16
amperes; 1.5,2.0, 2.5, 3.0, 4.0, 5.0 and 6.0 amperes;
0.5, 0.6, 0.8, 1.0, 1.2, 1.5 and 2.0 amperes; 0.1,
0.12, 0.16,
0.2, 0.24, 0.3 and 0.4 amperes.
These instructions do not purport to cover all details or variations in equipment nor to provide for
,}very possible contingency to be met in connection with installation, operation or maintenance. Should
further information be desired or should particular problems arise which are not covered sufficiently for
the purchaser's purposes, the matter should be referred to the General Electric Company.
To the extent required the products described herein meet applicable ANSI, IEEE and NEMA standards;
but no such assurance is gi ven wi th respect to local codes and ordinances bec~use they vary greatly.
3

GEH-1788 Type IAC Time Overcurrent Relay
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MULTIPLES OF RELAY TAP SETTING
Figure 3 <088880270 [3]) Time-Current Curves for Type IAC Relays with
Very-Inverse-Time Characteristics
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CALI BRATION
PLATE
ADJUSTABLE
POLE PIECE
INSTANTANEOUS
UNIT
OPERATING
COIL
TARGET
STATIONARY
CONTACTS
MOVING
CONTACT
ASSEMBLY
Fi g. L+
Type lAC Relay with an Instantaneous Unit
(Front View)
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:
Function
Amperes, a-c or d-c
2-Amp Tap
0.2 Amp Tap
Tripping Duty 30 5
Carry Continuously
3 0.3
Operating Range
2-30
0.2-2
Resistance
0.13
7
Impedance at 60 cy 0.53 52
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.
Type lAC Time Overcurrent Relay GEH-1788
SHORTING
COIL
MAIN
COIL
A-C
TRIPPING
UNIT
Fi g. S Type lAC Relay with an A-C Trip Unit
(Rear View)
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. 6.
Coil
Freq.
Tap Amps
Volt
Imp.
PF
Amps Amps
Ohms
4-16
60 4 5
2.0
0.08 0.50
50
4 5 1.7
0.07 0.50
25 4 5 1.3
0.05
0.61
1.5-6
60
1.5 5
14.5
0.58
0.42
50
1.5 5
12.0
0.48
0.42
25
1.5 5
9.0
0.36 0.55
0.5-2
60 0.5 5
105.0
4.20
0.35
50 0.5 5
86.0
3.45
0.34
25 0.5 5
82.0
3.28
0.55
* 3050
122
0.38
0.1-0.4
60
0.1
5
50 0.1 5
2546
102
0.36
------.
INSTANTANEOUS
INTRODUCTION
UNIT
The instantaneous unit is a small instantaneous
hinge-type unit which may be mounted on the right
front side of the induction unit (See Fig. 4). Its
contacts are normally connected in parallel with
the contacts of the main unit. Its coil is connected
in series with the operating coil of the main unit.
When the current reaches a predeterm:ned
value, the instantaneous unit operates, closing the
contact circuit and raising its target into view.
The target latches in the exposed position until
released by preSSing the button beneath the lower
left-hand corner of the relay cover.
5

GE8-1788 Type lAC Time Overcurrent Relay
26
24
22
20
18
16
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14
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601'\.1
50"",
25"V
TAP
RANGE
0.5-2.0
AMPS.
601'\.1 TAP
RANGE
50"", 1. 5-6.0
A~PS •.
25"", TAP
60"" J RANGE
501'\.1 4-16
251'V AMPS.
o 2 4 6 8 10 12 14
16 18
20
MULTIPLES OF MINIMUM PICK-UP CURRENT
SATURATION CURVES FOR lO~EST TAPS OF
INOUCTION UNITS ON VERY INVERSE
TYPE lAC RELAYS
Fig. 6 Saturation Curves for Lowest Taps of tne Induction Unit of Type lAC Relays with
Very-Inverse-Time Characteristics
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1'ype lAC Time Overcurrent Relay U~H-17aa
0.030
0.025
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en 0.020
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u 0.010
CL
0.005
o o 1 2 4
OPERATI NG TIME
RANGE FOR ~y
PICKUP SETIING
5 6 7
MULTIPLES Of PICK-UP
9
10
Fig. 7A (K-6306872 [5]) Time-Current Characteristics for Original Instantaneous Unit
.025 t---+----+-+_
".oro +---+---4
.oos +--+----!-+'__..
1.5 2 B 9
10
~ULTI PLES OF PICKUP
Fig. 7B (0208A869 5-1) Time-Current Characteristics for the "Hi-Gil Unit
7

GEH-1788 Type IAC Time Overcurrent Relay
APPLICATION
The instantaneous unit is used on certain Type
IAC relay models to provide instantaneous tripping
for current exceeding a predetermined value.
OPERATING CHARACTERISTICS
* The instantaneous unit operates over a four-
to-one range and has its calibration stamped on
a scale mounted beside the adjustable pole piece.
Time-current characteristics are shown in Fig.
7A for the instantaneous unit used before 1977.
In 1977 the instantaneous unit was modified to
make it have a higher seismic rating. The new
instantaneous unit can be identified by the mark-
ing "Hi -G" moulded into the front mouldi ng jus t
above the target windows. The time-current
characteristic for the "Hi-G" unit is shown in
Fig. 7B.
RATINGS
The instantaneous unit is designed to use
the coils listed below;
Coil Freq Amp
Volt-
Imp.
P.F.
Amp
Ohms
0.5-2
60 5 360 14.4 0.74
1-4 60 5 90
3.6
0.77
2-8
60 5 22.5
0.90 0.83
25 5
8.0
0.32 0.83
4-16
60
5 5.63 0.225
0.87
50 5
4.77
0.191 0.87
40 5 3.93 0.157
0.88
25 5
2.37
0.095 0.88
7-28
60 5 1.68 0.067
0.88
10-40
60 5 0.83 0.033
0.95
50 5
0.80 0.032 0.95
25 5 0.68
0.027
0.98
20-80
60 5
0.20
0.008 0.95
50 5 0.20 0.008
0.95
25 5 0.18
0.007
0.98
A-C TRIPPING UNIT
INTRODUCTION
The a-c tripping unit is a Type REA relay unit
designed to energize a circuit-breaker trip coil
from its associated cuz:rent transformer upon the
operation of the main unit of the Type IAC relay. It
transfers the current from the secondary of the
current transformer 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 tapped operating coil of the in-
duction unit (see Fig. 5). The operation of this unit
is illustrated in Fig. 11. The secondary current
8 * Indicates revision
circulates through the induction unit current coil and
the main coil of the Type REA auxiliary tripping unit,
returning through the Type REA contacts to the cur-
rent transformer. Normally, most ofthefluxgener-
ated by the main Type REA coil passes through the
upper limb of the magnetic structure and holds the
armature firmly against this limb. When the contacts
of the induction unit close, the shorting coil of the
Type REA unit is short-circuited and current flows
in this coil by transformer action, causing a redis-
tribution of flux which actuates the armature and the
Type REA contacts. The opening of the Type REA
contacts causes the secondary current to flow through
the trip coil which trips the breaker.

A-C 8~ S
TRIP BLS
(-) --.------
2
3
5 5
51-3
.a=.!
6 6
5
.llii.
H
6
-------
Figure B (K-6375667 [2]) External Connections of
Three Type IAC53A Relays Used for Phase-to-
Phase and Ground Overcurrent Protection of a
3-Phase Circuit
A-C BUS
Figure 9. (K6375668-1) External Connections of
Three Type IAC53A Relays used in Conjunction
with Tripping Reactors for Protection of a 3-Phase
Circuit
Type IAC Time Overcurrent Relay GEH-1788
Device Function Numbers for Use with ALL
51-1 External Diagrams
50
51
51N
52
SI
TC
A
Instantaneous Unit
Overcurrent Relay, Type IAC
Ground Overcurrent Relay, Type IAC
Power Circuit Breaker
Seal-in Unit, with Target
Trip Coil
Auxiliary Contact, closed
when breake .. • closes
A-C IIJS
~
IOC
Figure 10. (K-6375669-6) External Connections of
Three Type IAC53R Relays Used For 3-Phase
Circuit Protection
9

GEH-l'/MM 'rype IAC 'rime Overcurrent Relay
APPLICATION
The a-c tripping unit is used in Type IAC relays
where a reliable direct-current tripping source is
not available and it is necessary to trip the breaker
from the current-transformer secondary.
RATINGS
T6S1 BREAKER
TRIP COIL
The a-c tripping Wlit has a continuous rating of CURRENT
five amperes but will operate on a minimum current TRANS
of 3.5 amperes. It should be used with three-
ampere trip coils. The contacts of these units will
transfer current-transformer secondary current up
to 100 amperes. For applications where the sec-
ondary current exceeds 100 amperes, the Type
REAllB relay, which has contacts rated 200 am-
peres, can be used in conjWlction with Type IAC
overcurrent relays. The Type REAllB is not
mOWlted inside the Type IAC case.
aURDENS
Burdens of the Type REA unit are given in the
following table:
Impedance
PF
Volt-
Frequency Amps in Ohms
Amperes
60 5 0.49 0.80
12.2
50 5 0.33
0.80
8.3
25 5 0.23 0.62 5.8 *
Fig. II Diagram Illustrating Operation of Type
lAC Relays having an A-C Tripping Unit
RECEIVING, HANDLING AND STORAGE
These relays, when not included as a part of a
control panel will be shipped in cartons designed to
protect them against damage. Immediately upon
receipt of a relay, examine it for any damage
sustained in transit. If injury or damage resulting
from rough handling is evident, file a damage claim
at once with the transportation company and promptly
notify the nearest General Electric Apparatus Sales
Office.
Reasonable care should be exercised in Wlpack-
ing the relay in order that none of the parts are
injured or the adjustments disturbed.
If the relays are not to be installed immed-
iately, they should be stored in their original car-
tons in a place that is free from moisture, dust
and metallic chips. Foreign matter collected on
the outside of the case may find its way inside
when the cover is removed and cause trouble in
the operation of the relay.
INSTALLATION
LOCATION
The location should be clean and dry, free from
dust and excessive vibration, and well lighted to
facilitate inspection and testing.
MOUNTING
* The relay should be mounted on a vertical
surface. The outline and panel diagram is shown
in Fig. 20.
CONNECTIONS
The internal connection diagrams for the various
10 * Indicates Revision
relay types are shown in Figs. 12 to 17 inclusive.
Typical wiring diagrams are given in Figs. 8 to
10 inclusive.
One of the mounting studs or screws should be
permanently grounded by a conductor not less than
No. 12 B & S gage copper wire or its equivalent.
INSPECTION
At the time of installation, the relay should
be inspected fur tarnished contacts, loose screws,
or other imperfections. If any trouble is fOWld,
it should be corrected in the manner described
under MAINTENANCE.