GE IAC59A User manual

INSTRUCTIONS
UNDERCURRENT
GET-21903
F
Supersedes
GEI-21903
E
Insert
Booklet
GEI-1753
AND
OVERCURRENT
RELAYS
Types
IAC59A,
1AC59B,
and 1AC59(
GENERALS
ELECT’
IC

Undercurrent
and
Overcurrent
flelays
Type
IAC
Figure
1.
(IC-6400264)
Time-Current
Characteristics
for
IAC59C
Relays.
Figure
2.
(K-6400289)
Time-Current
Characteristics
for
Type
IAC59B
Relay
IQ
IC
0
C
Type
IAC59A
and
2

Undercurrent
and
Overcurrent
Relays
Type
IAC
(Ih1)
LJTOUT
.21V
_G8
7
DSLL
ECE
15M
E44UI.45
CASE
P
EL
(?
HOLES)
[tOLLED
1
\
(OFA
I
,Ltsruo
(2Vk4?4)
it
3 DRILL
VIEW SHOWIN
(IhLU)
IAMbA
00
E
1 DSILL
(Il
(to HOLES)
(9MM)
PAN DfILLING
F0l
MOHING
115
VOLTS RTE1i
HLQUNCY
MF2 IHMER
S 2
IAC
AOJUST6(
RES
Figure
5. (K-6400302)
Type
IAC59A
and IAC59B Relays,
Test Connections
PANEL
DWNG
F SDdI-FWSH
MOUNTING (FRONT
VIEW)
*
Figure
6. (6209271-6)
Outline
and
Panel Drilling
for the Type
IAC59A
Relay
*Indicates
revision
5

UNDERCURRENT
AND
OVERCURRENT
RELAYS
TYPE IAC
INTRODUCTION
These
instructions
are
a supplement
to
instruc
tion
book
GEH-1753
which
is
included
in
this
book.
The
combination
of
the
two
form
complete
instruc
tions
for
the
Types
IAC59A,
JAC59B
arid
IAC59C
relays.
The Type
IAC59A
relay
is
similar
in
construc
tion
and
operation
to
the
Type
IAC51A
relay,
des
cribed in
the
included
instructions,
except
that
it
has
double
throw
contacts
with
a
seal-in
unit
for
each
contact.
The
left-hand
contacts
are
adjusted
to
close
at
tap
value
of
current
while
the
right-hand
contacts
may be
adjusted
to
close from
50
to
95
percent
of
tap
value.
The
Type
IAC59B
relay
is
similar
to
the
Type
IACS9A
relay
except
that
it is
a
short
time relay
adjusted
to
close its
right-hand
contacts
when
the
current
is
reduced
to
tap
value.
The
left-hand
con
tact
may
be
adjusted
to
close
from
105
to
150
per
cent
of
tap
value.
MOUNTING
The
outline
and
panel
drilling
dimensions
for
these
relays
are
shown in
Fig.
6
of
this
supplement,
CON
NECTIONS
Internal
connection
diagrams
are
shown
in fig.
3 and
Fig.
4
inclusive.
ADJUSTMENTS
AND
TESTS
With
connections
as
shown
in
Fig.
5
pickup
ad
justments
and
time
checks
may
be
made.
The
relay is
energized
for
pickup
or
dropout
check
by
closing
Si.
Unless
otherwise
requested
the
IAC59A
is
set
at
the
factory
to
close
its
right
contacts
at
80%
of
tap
value and
the
IAC59B
is
set
to
close
its
left
contacts
at
110%
of
tap
value.
If
it
is
desired
to
change
this
percentage
or
contact
spread,
the
following
procedure
is
necessary.
Turning
the
spring-adjusting
ring, as
described
under
“current
setting”
of
the
included
instructions,
affects
primarily
the
current
required
to
close
the
left
contacts,
Rotating
the
right-hand
moving
con
tact,
after
loosening
the
clamping screws
holding
it
The
Type
LAC59C
relay
is
similar
to
the
Type
IAC59A
relay
except
that
the
seal-in
units
are
omitted.
BURDENS
Burdens
for
the
various relay
ratings
at
mini
mum
pick-up
current
and
60
cycles
are
given
in
the
following
table:
Mm—
Cont.
Relay Tap
Pick-
Cur-
Volt-
Imp. P,F.
Type Range
up rent Amps
Ohms
IAC59A
0,5-2
0,5
5
1,17 4,71 .27
IACS9C
1.5—6
1.5 15 1,17 0,52
.25
4-16
4.0 15 1.36
0.08
.38
IAC59B
0,5-2
0.5 2.5 4.72
18,90
.29
1.5—6
1,5
7,5
4,68 2.08
.26
4—16
4,0 15
I492
0,31
.27
in
place, changes
the
current
required
to close
the
right contacts,
Each
of
these adjustments
affects
the
other,
hence simultaneous
adjustment
for
clos
ing
left
and
closing
right
must
be
made
to
obtain the
desired
contact
spread,
The
relays
are
adjusted
at the factory
to
give
the
time
characteristics
shown
in
Fig.
1
and
Fig.
2,
The
time
may
be
changed
slightly
by
changing
the
position
of
the
permanent
magnet
on
its
supporting
shelf.
In
general,
moving
the
magnet toward
the
back
of
the
relay
decreases
its
time
of
operation.
To
check
overcurrent
time, suddenly
apply
the
desired
preset
current
to
the
relay
by
closing
Si.
The
time
read
on
the
timer
is
that
required
to
close
the
left contacts.
To
check the
undercurrent
time close
Si
and
S2
and,
using Ri,
adjust
the
current
to
a
value
greater
than
that required
to
close
the
left-hand
contacts.
With
S2
open,
use
R2
to
set
the
current
to
the
desired
value
below
the
current required
to
close
the
right-hand contacts.
Then
with
Sl
and
S2
both
closed,
open
S2.
The
time
read
on
the
timer
is
that
required
for
the
right
contacts to
close
when
the
current
is
suddenly
reduced
from
a
value
sufficient
to
close
the
left-hand
contacts,
to
a
predetermined
value,
INSTALLATION
These
instructions
do
not
purport
to
cover
ll
details or
variations in
equipment nor
to
provide for
every
possible contingency
Co
be
met
in
connection
with
installation, operation or
maintenance. Should
further
information
be
desired
or should
particular problems
arise
which
az-c
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 applicablo
ANSI, IEP’E
and
WEMA
standards;
but
no such assurance
is
given with
respect
to
loca 7
codes
and
ordinances
because
they
vary
greatly.
3

OPERATING
CO
I
L
Figure
3.
(K-6400242)
Type
IAC59A
and
IAC59B
Relays
Internal
Con
nections
(Front
View).
Un&rcurrent
and
Overcurrent
Relays
Type
IAC
SEAL—I
N
ELEMENT
9
SHORT FINGER
OPERAT
I
NO
COIL
LI.
4
—
SHORT
FINGR
Figure
4.
(K-6400432) Type
IAC59C
Relay
Internal
Connections
(Front
View).
4

GENERAL ELECTRIC
COMPANY
POWER
SYSTEMS
MANAGEMENT
BUSINESS
DEPT.
PHILADELPHIA,
PA.
19142
GENERAL
ELECTRIC
7-80
2-(8

000 CJ1UU1
-
-
-
-v m
00
C,
m
m
I
3
m
I
0
m
C)
C
m
z
-I
r
11<
U)
-I
C
n
-I
5
z = I

GEH-1753
Time
Overcurrent
Relays
Type
IAC
TOP
PIVOT
-
_____________
TAP
PLUG
SEAL-IN
UNIT
HOLDING COIL
SEAL-IN
(j
SEAL-IN
UNIT
STATIONARY
CONTACT,
LEFT
SEAL-IN
UNIT
STATIONARY
CONTACT,
RIGHr
SEAL-IN
MOVING
CON
TA CT
ASSEMBLV
A
-
(S006996)
Front
View
B
—
(8006997)
8ar
View
FiBur
B
educLicnj
Ln
L
or
Tvp- JAC
Re
1ay
—
/
r’ 1
LOWER
JEWEL
SCREW—_3
2

TIME-OVERCURRENT
RELAYS
TYPE
IAC
INTRODUCTION
Contact
Instantaneous
AC
Trip
Induction
Outline
&
Internal
Typ.
Circuits
Unit
Unit
Unit
Panel Drilling
Connection
LAC5IA(-)A
One
Nn
No
One
Fig.
18
Fig.
II
IAC51B(-)A
One
Yes
No
One
Fig.
18
Fig.
12
LAC51R(-)A One
Yes
Yes
One
Fig.
18
Fig.
13
LAC52A(-)A
Two
No
No
One
Fig.
18
Fig.
14
LAC52B(-)A
Two
Yes
No
One
Fig.
18
Fig.
15
The
Type
IAC
relays
comprise
agroup
of
relays
that
are
employed
to
protect against
overcurrent
on
single-phase
and
polyphase
circuits.
The
various
relays
in
this
IAC
group
are
identified
by model
numbers,
and
the
relays
differ
in
the
number
of
circuits
they
close,
the
length
of
time
delay
and
features
that
are
determined
by
the
characteristics
of
the
protected
circuit.
These
relays
consist
of
an induction
unit
or
an
induction
unit
with
an
instantaneous
unit
which
permits
instantaneous
tripping
for
extremely
high
currents,
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
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
con
venience,
described
separately
in
the
following
text.
The
above
table
indicates
the
units
comprising
each
type and
also
lists
the
internal
connections
and
out
line
and
panel
drilling
diagrams.
INDUCTION
UNiT
INTRODUCTION
The
induction
unit
is
the
basic
unit
in
all
TAC
relays.
Fig.
1
shows
the
induction
unit
mounted
in
the
cradle.
These
units
are
of
the
induction-disk
construction
type. The
disk
is
actuated
bya
current
operating
coil
on
a
laminated
U-magnet.
The
disk
shaft
carries
the
moving
contact
which
completes
the
alarm
or
trip
circuit
when
ittouchesthe
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.
APPLICATION
The
induction
unit
is
the
main
unit
in all
IAC
relays,
supplying
the
inverse
time
delay
character
istics
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
settingofthetirnedial(Fig.
1).
The
time—current
characteristics are
shown
in
Fig.
2.
RAflNGS
The
induction
element
is
designed
to
use
any
one
of
three
operating
coils,
each having
a
different
combination
of
taps
as follows:
4, 5,
6, 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
am
peres.
‘1rnnc
instructions
do
not
purport
to cover
all
details
or
variations
in equipment
nor
to provide
for
every
lcnsll)le continqency
to
be
met
in connection
with
installation,
operation
or
maintenance.
Should
furLhr
in
formatIon
be
desired
or should
particular
problems
arise
which
are
not
covered
sufficiently
for
th
purchaser’n
curpcrnes,
the
matter
should
be referred
to
the General
Elect
rIc
Company.
Te
t5e
extent
required
the
products described
herein
meet
applicable
1,1151,
IEEE
and
NEM.
standards;
no
rninh
rnsnrnnce
is given
with
respect
to
local
codes
and
ordinances
because
they
vary
greatly.
3

GEH-1753
Time
Overcurrent
Relays
Type
IAC
In
z
a
C-)
In
z
MULTIPLES
OF
RELAY
TAP
SETTING
Fig.2.
(0888R0269
3J)
Time—current
Curves
of
Type
1AC
Relays
with
inverse—lime
Characteristics
4

Time
Overcurrent
Relays
Type
IAC
GEH-1753
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
(see)
0.05
2.2
0.5
3.5
Carry
10
amps for
(see)
0.45
20
5.0
30
Carry
conflnuously
(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
(ohms)
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.
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
Volt-
Imp.
P
F
Freq.
Tap
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
21.2
0.26
50
0.5
470.0
18.8
0.28
25
0.5
430.0
17.2
0.34
V
0
T
A
E
9
6
3
0
/
----r-
/
//
——--
--V.77
———
—--————
—-
/--—---
I
r—
0
2
4
6
B
10
12
14 16
18
UULTIPLIS
OF
MINIVuM
TAP
SCTtING
SATURATIOH
CuRVIS
AT
VARIOUS
FREQUt6CIS
FOR
3
TAP
RAUGIS
OF
TI4t
TYP(
IACSIA
RE1A
LOAEST TAP
USED IN
ALL CASES
TAP
.5—2.0
TAP
RANGE
1.5—6.0
AU
PS.
TAP
68
GE
4—16
5D..jAUPs.
Fig.
3.
(K—6306$91-1)
Snturatzi
on
Curves
for
I
OWL
,ips
i I.
h
1nuctioi1
Unit
01
Zype
1.AC
Re].oys
\JiLL
1nvers
—time
flarflCturisI1t.
25
60
50
42
36
36
33
30
27
24
21
18
5

GEH-1753
Time
Overcurrent
Relays
Type
IAC
DEVICE
FUNCTION NUMBERS
FOR
USE
WITH
ALL
EXTERNAL
DIAGRAMS
50
-
Instantaneous
Unit
51
-
Overcurrent,
Relay,
Type
IAC
51N
-
Ground
Overcurrent
Relay,
Type
IAC
52
-
Power
Circuit
Breaker
SI -
Seal-in
Unit,
with
Target
TC
-
Trip
Coil
A
-
Auxiliary contact,
closed
when
breaker
closes.
Fig.
5
(K631S668-l)
Ritvrnal
CnntcLions
of
‘i:,rc•e
Type
C5[i\
lu-Jays
used
in
Conjunction
with
Tripping
Re.,cLors
f’r
Eretction
of
a1
re&—Pnase
(
Lrcuit
Fig.
4
(K-6375667-2)
External
Connections
of
Three
Type
IAC51A
Relays
used
for
Phase-to-Phase
and
Ground
Overcurrenc
Portectjon
of
a
3—Phase
Circuit.
Fig.
6
(K-6375669-6)
External
Connections
of
Three
Tyn
IAC5TR
Relays
used
for
3-Phase
CircuiL
PruLetion.
A-C
ALJS
eus
3
6

Time
Overcurrent
Relays
Type
IAC
GEH-1753
INSTANTANEOUS
UNIT
INTRODUCTION
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.
7).
Its
contacts
are
n r
mally
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
predetermined
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.
APPLICATION
The
instantaneous
unit
is
used
on
certain
IAC
relay
models
to
provide
instantaneous tripping
for
current
exceeding
a
predetermined
value.
OPERATING
CHARACTERISTICS
The
instantaneous
element
operates
over
a
4
to
I
range
and
has
its
calibration
stamped
on
a scale
mounted
beside
the
adjustable
pole
piece. Time-
current
characteristics
are
shown
in
Fig.
10.
RATINGS
The
instantaneous
unit
is
designed
to
use
either
of
two
coils
having pickup
ranges
of 10
to
40,
and
20
to
80
amperes respectively.
The
current-closing
rating
of
the
contacts
is 30
amperes
for
voltages
not
exceeding
250
volts.
BURDENS
Burden
data
on
the
instantaneous
unit
coils
are
given
in
the
following
table:
Volt Imp.
F
Coil
Freq.
Amp.
Amp
Ohms
10-40
60
5
0.83
0.033
0.95
50
5
0.80 0.032
0.95
25
5
0.65
0.027
0.98
20-80
60
5
0.21
0.008
0.95
50
5
0.20 0.008
0.95
25
5
0.15
0.007
0.98
C
AL
It
RATION
-
-
VVIPLATE
ADJUSTABLE
________
POLE
PIECE
IN$1ANTANOUS
.
UNT
OPEATINO
r
COIL
TARGET
L=
STATIONARY
V:
CONTACTS
MOVING
CONTACT
[
h
ASSEMBLY
I
(.IM
RALL
V
Vjfl[
Fig.
7. (bOO6,9ct)
jyiw
TAC
R1ay
with
an
lilt
ifltafle.ius
IniL.
F
t.
8.
(61)07060)
I’i
iiL
R
lay
with
an
A—(V:
;if)iLIi
[nit
____
.4
—
-‘
Li’’.
I
•
—
—
V
!V
VVV
SHORTING
—
--
MAIN
COIL
I
AVC
—TRIPPING
—
7

GEH-1753
Time
Overcurrent
Relays
Type
IAC
INTRODUCTION
A-C
TRIPPING
UNIT
The
a-c
tripping
unit
is
a
Type
REA
relay
unit
designed
to
energize
a
circuit
breaker
trip
coilfrom
its
associated
current transformer
upon
the
operation
of
the
main
unit
of
the
IAC
relay.
It
transfers
the
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
tapped
operating
coil
of
the
induction
unit
(see
Fig.
8).
The
operation
of
this
unit
is
illustrated
in
Fig.
9.
The
secondary
current
circulates
through
the
induction
unit
current
coil
and the
main
coil
of
the
REA
auxiliary
tripping
unit,
returning
through
the
REA
contacts
to
the
current
transformer.
Normally,
most
of
the
flux
generated
by
the
main
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
REA
is
short-circuited
and
current
flows
in
this
coil
by
transformer
action, causing
a
redistribution
of
flux
which
actuates
the
armature
and the
REA
contacts.
The
opening
of
the
flEA
contacts
causes
the
secondary
current
to flow
through
the
trip
coil
which
trips
the
breaker.
U,
___ ___
___ ___
a
‘-‘
0.010
0.
Fig.
9
(K-6154766—2)
Diagram
Illustrating
OperatioiT
of
Type
TAG
Relays having
an
A-C
Tripping
Unit.
MULTIPLES
OF PICK—UP
Fig.
10
(6306872
15))
Time—current
Characteristics
of
Original Instantaneous
Unit
• AC
TRIP
IJRIr
HO
I. LV
CLOSED
CON1ACTS
AC
TRIP
UNIT
sOR1
INC
coit
AC
TRIP
UNIT
MAIN
COIL
0.030
0.025
0.
Ct20
0.015
___
I
OPERATING
TIME
,
c—
RANGE
FOR
ANY
PICKUP
SETTING
—
0.005
0
0
1
2
3
4
5
6
7
b
10
8

Time
Overcurrent
Relays
Type
IAC
GEH-1753
APPLICATION
The
a-c
tripping
unit
is
used
In
Type
LAC
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
The
a-c
tripping
unit
has
a
continuous
rating
of
five
amperes
but
will
operate
on
a minimum
current
of
3.5
amperes.
They
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
second
ary
current
exceeds
100
amperes,
the
REA11B
relay,
which
has
contacts
rated
200
amperes,
can
be
used
In
conjunction with
IAC
overcurrent
relays.
The
REA11B
is
not
mounted
Inside
the
IAC
case.
BURDENS
Burdens
of
the
REA
unit
are
given
in
the
following
table:
Impedance
P
F
Volt-
Frequency
Amp
in
Ohms
Amperes
60
5
0.49
0.80
12.2
50
5 0.33
0.85
8.4
25
5
0.23
0.62
5.8
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 the
relay,
an
examination
should
be
made
for
any
damage
sustained
during
shipment.
If
injury
or damage
resulting
from rough
handling
is
evident,
a claim
should
be
filed
t
once
with the
transportation
company
and
the
nearest
Sales
Office
of
the
General
Electric
Company
notified
promptly.
Reasonable
care
should
be
exercised
in
Un
SEAL—I
N
UN
T
packing
the
relay
in
order
that
none
of
the
parts are
injured
or
the
adjustments
disturbed.
If
the
relays
are
not
to
be
Installed immediately,
they
should
be
stored
In
their
original
cartons 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.
IN
DUC
TIC
N
Li
NIT
6
INTERNAL
CONNECTIONS
(FRONT
VIEW)ZSHORT
FINGER
Fig.
ii.
(K-6209658-IO)
Internal
Connection
fo:
tw
ype IAC5IA
Relay
(Front View).
SHORT
FINGER
Fig.
12.
(K—6209661
Ill)
Internal
Connections
for
the
Type
IAC51E Relay
(Front
View)
SEAL—
IN
UNIT
1
5
2
6
2
5
9

GEH-1753
Time
Overcurrent
Relays
Type
IAC
INDUCTION
UNIT
SI
SL—IN
UNIT
SHORT
FINGER
Fig. 14
(K—6209662
(5])
Internal
ConnectionB
for
the
Type
IAC52A
Relay (Front
View)
SEAL—IN A—C
RIP
UNIT
I
NSTANT.
UI.i
Fig. 13
(K-6209294-3)
Internal
Connections
for
the
Type
IAC51R
Relay
(Front
View)
INDUCT
I
ON
L
j\j
rJS’4
6
10

Time
Overcurrent
Relays
Type
IAC
GEH-1753
To
TIMER
STOP”
TO
TIMER
“START”
lAIN.
RECC**AENDED
VOLTS,
120
AT
RATED FREQUENCY
1
‘1
IC’
INCICATINC;
LIGHT
‘MC?l
CIILCYINC,
PICKUP
OF
IAAIN
UNIT
1)
IDICATING
LIGI-IT
ANtI
CHFCKINL I’ICKUP
OF
I
N,TANTANEOLS
UNIT
To
ACCURATELY
REPROWCE
RELA’ CHARACTERISTICS
ALL
TESTS
SHOULD
BE
WDE WITH
RELAY
IN
CASE.
Fig.
15
01—6209663
[8])
Internal
Connections
for
the
Type
IAC52B
Relay
(Front
View)
Fig.
16
(K-6154399.-7)
Testing
Connections
for
Type
[AC
Relays
such
as
Type
IAC51A
INSTALLATION
LOCATION
The
location
shou:ld
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 diagrams
are
shown
in
FIgs.
20
and
21.
CONNECTIONS
Internal
connection
diagrams
for
the
various
relay
types
are
shown
in
Fig.
11
to
17
inclusive.
Typical
wiring
diagrams
are
given
in
Fig.
4
to
6
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.
INSPLCTION
At the
time
of
installation,
the
relay
should
be
Inspected
for
tarnished
contacts,
loose
screws,
or
other
imperfections.
Ti
any
trouble
is
found,
it
should
be corrected
in
the
manner
described
under
MAINTENANCE.
CAUTION:
Every
circuit
in
the
drawout
case
has
an
auxi
liary
brush.
It
is
especially
important
on
current
circuits
and
other
circuits
with
shorting
bars
that
the
auxiliary
brush
be
bent
high enough to
engage
the
connecting plug
or
test
plug
before
the
main
brushes
do.
This
will
prevent
CT
secondary
cir
cuits from
being opened.
AUXILIARY
BRUSH —i
TERMINAL
BLOCK
NOTE’
AFTER
ENGAGING
AUXILIARY
BRUSH.CONNECTING
PLUG
TRAVELS
1/4
INCH
BEFORE
ENGAGING
THE MAIN
BRUSH
ON
HE
TERMINAL
BLOCK.
Fig.
17
(8025039)
Cross
Section
of
Drawout
Case
Showing
Position
of
Auxiliary
Brush.
SEAL—I
N
115
IT
I
NSTANT.
Ut
I
I
-
-
-
-1-
-
-
—
0
1
2
3
4
5
0
0
00
7
II
9
10
INSTANT.
UN
I
T
1
XLA13
TEST
PLIJG
-VARIABLE
RESISTOR
3
5
9
.
SHORT
FINGER
CONNECTING
PLUG MAIN
BRUSH
CONNECTING
BLOCK
11

GEH-1753
Time
Overcurrent
Relays
Type
L&C
ADJUSTMENTS
TARGET
AND
SEAL-IN
UNIT
For
trip coils operating
on
currents
ranging
from
0.2
up
to
2.0
amperes
at
the minimum
control
voltage,
set
the
target
and seal-in
tap
screw
in
the
0.2-ampere
tap.
For
trip
coils operating
on
currents
ranging
from
2
to
30
amperes
at
the
minimum
control
volt
age,
place
the
tap plug
in
the
2-ampere
tap.
The tap
screw
is
the
screw
holding
the
right-
hand
stationary
contact
of
the
seal-in
unit.
To
change
the tap
setting,
first
remove
the
connecting
plug.
Then, take
a
screw
from
the
left-hand
station
ary contact
and
place
it
in
the
desired
tap.
Next,
remove
the
screw
from
the
other tap,
and
place
it
in
the
left-hand
contact. This
procedure
is
neces
sary
to
prevent
the right-hand
stationary
contact
from
getting
out of
adjustment.
Screws
should
not
be
in
both taps
at
the
same
time.
INDUCTION
UNIT
CURRENT
SETTING
The tap
plug
must
not
be
removed
without
first
withdrawing
the
connecting
plug.
The
current
at
which
the
contacts
operate
may
be
changed
by
changing
the
position
of
the
tap
plug
in
the
tap
block
at
the
top
of
the relay.
Screw
the
tap
plug
firmly
into
the tap
marked
for
the desired
current
(below
which
the
unit
is
not
to
operate).
When
changing
the
current
setting
of
the
unit,
remove
the
connecting
plug to
short
circuit
the
cur
rent
transformer
secondary
circuit.
Next,
screw
the tap
plug
into tap
marked
for the
desired
current
and
then
replace
the
connecting
plug.
The
pickup
of
the
unit
for
any
current
tap
is
adjusted
by
means
of
a
spring—adjusting
ring.
The
ring
may
be
turned
by
inserting
a
screw
driver
in
the notches
around
the
edge.
By
turning
the
ring,
the operating
current
of
the
unit
may
be
brought
into agreement
with
the
tap
setting
employed,
if
for
some
reason,
this adjustment
has
been
disturbed.
This
adjustment also
permits
any
desired
setting
Intermediate
between
the
various
tap settings
to
be
obtained.
The
unit
is
adjusted
at
the
factory
to
close
its
contacts
from any
time-dial
position at
a
mini
mum
current
within
five
percent
of
the
tap-plug
setting.
The unit
resets
at
90
per
cent
of
the
mini
mum closing
value.
TIME
SETTING
The setting
of
the
time dial
determines
the
length
of
time
the
unit requires
to
close its
contacts
when the
current
reaches a
predetermined
value.
The
Contacts
are just
closed
when
the
dial
is
set
on
0.
When
the dial is
set
on 10,
the
disk
must
travel
the
maximum amount
to
close
the
contacts
and
there
fore
this setting
gives
the
maximum
time
setting.
The primary
adjustment
for
the
time
of
opera
tion
of
the
unit
is
made by
means
of
the
time
dial.
However,
further
adjustment
is
obtained
by
moving
the permanent
magnet
along
its
supporting
shell;
moving the
magnet
toward
the
disk shaft
decreases
the
time,
while moving
It
away
increases
the
time.
If
selective
action
of
two
or
more
relays
Is
required, determine
the
maximum
possible
short-
circuit
current
of
the line
and
then
choose
a
time
value
for each
relay
that
differs
sufficiently
to
in
sure
the
proper
sequence
in
the
operatiop
of
the
several
circuit breakers.
Allowance
must
le
made
for
the
time
involved
in
opening
each
breakr
after
the relay
contacts
close.
For
this
reason,
unless
the
circuit
time
of
operation
is
known
with
accuracy,
there
should
be
a
difference
of
about
0.5
second
(at
the
maximum
current)
between
relays
whose
opera
tion is
to
be
selective.
EXAMPLE OF
SETTING
The
time
and
current
settings
of
the
overcurrent
unit can
be
made
easily
and
quickly.
Each
time
value
shown
in
Fig. 2
indicates
the
time
required
for
the
contacts
to
close
with
a
particular
time-dial
setting
when
the
current
is
a
prescribed
number
of
times
the
current-tap
setting.
In
order
to
secure
any
of
the
particular time-current
settings
shown
In
Fig. 2,
insert
the
removable
plug
in
the
proper
tap
re
ceptacle
and
adjust
the
time-dial
to
the
proper
position.
The following
example
illustrates
the
procedure
in
making
a
relay
setting.
Assume
a
Type
IAC
relay is
used In
a
circuit
where
the
circuit
breaker
should
trip on
a
sustained
current
of
approximately
450
amperes;
also,
the
breaker
should
trip
in
1.9 secons
ona
short-circuit
current
of 3750 amperes.
Assume
further
that
current transformers
of
60/1
ratio
are
used.
The current
tap
setting
Is found
by
dividing
the
minimum
primary
tripping
current
by
the
current
transformer
ratio.
In
this
case,
450
divided
by
60
equals
7.5
amps.
Since
there
is
no
7.5-amp
tap,
the
8-amp.
tap
is
used.
To
find
the
proper
time-dial
setting
to
give
1.9 seconds
time
delay at
3750
am
peres,
divide
3750
by
the
transformer
ratio.
This
gives
62.5
amperes
secondary
current
which
is
7.8
times
the
8-ampere
setting.
By
referring
to the
time current
curves
(Fig.
2),
it will
be
seen
that
7.8
times
the
minimum
operating
current
gives
1.9
seconds
time
delay
when
the
relay
is
set
slightly
above
the
No.
6
time-dial
setting.
The above
results
should
be
checked
by
neans
of
an
accurate
timing
device.
Slight
readjustment
of
the dial
can
be
made
until
the
deired
time
is
obtained.
Aid
in
making
the
proper selection
of
relay
settings
may be
obtained
on
application
to
the
nearest
Sales
Office
of
the General
Electric
Company.
12