GE IACS1A User manual

GEK—34053G
TYPES
IACS1A
FORM
800
AND
UP
IACS1B
FORM
800
AND
UP
IACS2A
FORM
800
AND
UP
IAC52B
FORM
800
AND
UP
INSTRUCTIONS
TIME
OVERCURRENT
RELAYS
GENERAL
ELECTRIC

GEK-34053
TABLE
OF
CONTENTS
DESCRIPTION
APPLICATION
CONSTRUCTION
RATINGS
TIME-OVERCURRENT
UNIT
INSTANTANEOUS
UNIT
TARGET
AND
SEAL-IN
UNIT
.
CONTACTS
BURDENS
CHARACTERISTICS
RECEIVING,
HANDLING,
AND
STORAGE
ACCEPTANCE
TESTS
VISUAL
INSPECTION
MECHANICAL
INSPECTION
ELECTRICAL
TESTS
DRAWOUT
RELAYS,
GENERAL
POWER
REQUIREMENTS,
GENERAL
TIME-OVERCURRENT
UNIT
TIME
SETTING
PICKUP
TEST
TIME
TEST
INSTANTANEOUS
UNIT
SETTING
THE
INSTANTANEOUS
PICKUP
TEST
TARGET
AND
SEAL-IN
UNIT
PICKUP
AND
DROPOUT
TEST
INSTALLATION
TIME-OVERCURRENT
UNIT
TARGET
AND
SEAL-IN
UNIT
INSTANTANEOUS
UNIT
PERIODIC
CHECKS
AND
ROUTINE
TIME
OVERCURRENT
UNIT
INSTANTANEOUS
UNIT
TARGET
AND
SEAL—IN
UNIT
CONTACT
CLEANING
-
SYSTEM
TEST
SERVICING
TIME-OVERCURRENT
UNIT
PICKUP
TESTS
.
TIME
TESTS
INSTANTANEOUS
UNIT
TARGET
AND
SEAL-IN
UNIT
RENEWAL
PARTS
LIST
OF
FIGURES
(Cover
photo
8041316)
UNIT
MAINTENANCE
PAGE
3
4
4
5
5
6
7
7
8
9
9
...
9
•
.
•
10
•
.
.
10
•
.. 10
10
•
.
•
11
•
..
11
•
.
.
11
•
.
•
12
•
••
12
•
.
.
12
•
.
.
12
•
.
•
12
•
..
13
•
.
.
13
•
..
14
•
..
14
••
.
14
14
15
•
.
•
15
•
..
15
•
.
.
15
•
.
•
15
15
••
.
16
•••
16
•
.
.
16
•
.
•
17
•
•
.
17
•
..
18
•
.
•
18
•
.
19
2

GEK-34053
TIME OVERCURRENT
RELAYS
DESCRIPTION
The
Type
IAC51
and
1AC52
relays
are
single—phase,
current—
operated,
AC
devices
with
inverse
time/current
characteristics.
They
are
utilized
to
protect
commercial,
industrial,
and
utility
power
distribution
systems
against
either
multi—phase
or
phase—to—ground
faults.
Each
relay
consists
of
a
basic
induction—disk
time—overcurrent
unit,
and
a
dual—rated
target/seal—in
unit,
and
may
include
a
hinge—
type
instantaneous—overcurrent
unit.
Both
the
time—overcurrent
unit
and
the
instantaneous
unit
are
adjustable
over a
range
of
about
8
to
1.
The
available
ranges
in
amperes
of
both
units,
as
well as
information
on
their
continuous
rating,
contact
rating,
and
target/seal—in unit
tap
ratings
are
given
in
the
section
on
RATINGS.
A
standard
Si
case
is
used to
mount
each
relay.
The
outline
and
mounting
dimensions
of
this
case
are
shown
in
Figure
12.
The
basic
differences
between
the
relays
covered
by
these
instructions
are
noted
in the following
table:
TYPE
INSTANTANEOUS CONTACT
INTERNAL
UNIT
CIRCUIT
CONNECTIONS
IACS1A
NO
1
FIGURE
4
IAC51B
YES
1
FIGURE
5
IAC52A
NO
2
FIGURE
6
IAC52B
YES
2
FIGURE
7
The.se
instructions
do
not
purport to
cover
all
details
or
variations
in
equipment
nor provide
for
every
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
given,
with
respect
to
local
codes
and
ordinances
because
they
vary
greatly.
3

GEK-34053
APPLICATION
The
inverse
time—current
characteristics
make
the
IAC51
and
IACS2
relays
well
suited
for
multi—phase
and
phase—to—ground
fault
protection
of
commercial,
industrial,
and
utility
distribution
systems,
and
frequently
for
overload
back-up
protection.
They
are
particularly
well
suited
for
application
in
locations
where
the
fault—current
magnitude
is
dependent
mainly
upon
the
location
of
the
fault relative
to the
relay
and
only
slightly
upon
the
system
generating
setup
at
the
time
of
the
fault.
The
general
practice
is
to
use
a
set
of
three
relays
for
interphase
faults
and
a
separate
relay,
residually
connected,
for
single—phase—to—ground
faults.
Use
of
a
separate
ground
relay
is
advantageous
because
it
can
be
adjusted
to
provide
more—sensitive
protection
on
ground
faults.
Typical
connections
for
such
an
application
are
shown
in
Figure
14.
A
typical
application
and
external
connections
of
the
IAC52A,
which
has
two
closing
contacts, is
shown
in
Figure
15.
Care
should
be taken
in
applying
this
relay,
since
simultaneous
closing
of
both
contacts
may
not
occur.
In
the
application
of
IAC51
and
52
relays
with
automatic
reclosing
devices,
the
reset
time
should
be
considered.
The
reset
time
of
all
relays
covered
by
these
instructions
is
approximately
seven
seconds
(7 secs),
from
the
fully—closed
to
the
fully—open
position,
when
set
at
number
10
on
the time
dial.
When
setting
these
relays
to coordinate
with
downstreamu
relays,
a
coordination
time
of
from
0.25
to
0.40
second
is
generally
allowed.
These
coordination
times
include,
in
addition
to breaker—clearing
time,
0.10
second
for
relay
overtravel
and
0.17
second
for
safety
factor.
For
example,
if
the breaker—clearing
time
is
0.13 second
(8
cycles),
the
coordination
time
would
be
0.40
second.
If
the
relay
operating
time
is set
by test
at
the
current
level
in
question,
the
safety factor
may
be
reduced
from
0.17
to
0.07 second
with
relay
overtravel
of .10
second.
Then
if the
“downstream”
breaker
time
is
5
cycles
(0.08
sec)
a
minimum
of
0.25
second
could
be
allowed
for
coordination.
CONSTRUCTION
The
induction
unit
is
the
basic
unit
in
all
Type—IAC
relays.
Figures
2
and
3 show
the
induction
unit
mounted
in
the
cradle.
These
units
are
of
the
induction—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
stationary
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
target
and
seal—in
unit
mounted
on
the
front,
to
the
left
of
the
shaft
of
the
time—overcurrent
unit.
The
seal—in
unit
has
its
coil
in
series
and
its
contacts
in
parallel
with
the
contacts
of
4

GEK-34053
the
time—overcurrent
unit,
such
that
when
the
induction—unit
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
instantaneous
unit
is
a
small
hinge—type
unit,
which
is
mounted
on
the
front
of
the
B
models
to
the
right
of
the
shaft
of
the
time—overcurrent
unit.
Its
contacts
are
normally
connected
in
parallel
with
the
contacts
of
the
time—overcurrent
unit
and
its
coil
is
connected
in
series
with
the
time—overcurrent
unit.
When
the
instantaneous
unit
picks
up
it
raises
a
target,
which
latches
up
and
remains
exposed
until
it
is
released.
The
same
button
that
releases
the
target
of
the
seal—in
unit
also
releases
the
target
of
the
instantaneous
unit.
RATINGS
TIME-OVERCURRENT
UNIT
Ratings
for
the
time—overcurrent
unit
are
shown
in Table
I.
TABLE
I
PICKUP
RANGE,
AMPERES
RELAY
FREQUENCY
MAIN
(TIME)
INSTANTANEOUS
CYCLES
UNIT UNIT
IAC51A
and
50
0.5
-
4.0
IAC52A
60
2.0
-
16.0
IAC51B
and
50
0.5
-
4.0
0.5
—
4.0
IAC52B
60
2.0
—
16.0
2.0
-
16.0
10.0
-
80.0
20.0
-
160.0
Available
taps
of
the
time—overcurrent
unit
are
shown
on
Table
II.
TABLE
II
RANGE,
AMPERES
TAPS
AVAILABLE
(AMPERES)
0.5
-
4.0
0.5,
0.6. 0.7,
0.8
1.0,
1.2, 1.5,
2.0,
2.5, 3.0,
4.0
2.0
-
16
2.0, 2.5,
3.0,
4.0,
5.0,
6.0, 7.0,
8.0,
10.0,
12.0.
The
one—second
thermal
ratings
are
listed
in Table
III.
5

GE
K-34053
TABLE
III
TIME
OVERCURRENT
UNIT
ONE
SECOND
K
(AMPS) RATJNG(AMPS)
0.5
-
4.0
70.0
4,900.0
2.0
-
16.0
260.0
67,600.0
For
ratings
for
less
than
one
second,
the
rating
may
be
calculated
according
to
the
formula
K
T
where
T
is
the
time,
in
seconds,
that
the
current
flows.
The
continuous
ratings
of
the
time—overcurrent
units
are
shown
in
Tables
IV
and
V.
TABLE
IV
0.5
-
4.0
AMP RANGE
TAP
0.5 0.6
0.7
0.8
1.0
1.2
1.5
2.0
2.5 3.0
4.0
RATING
1.6
1.8
2.0
2.1
2.3 2.7
3.0
3.5
4.0 4.5
5.0
TABLE
V
2.0
-
16.0
AMP
RANGE
TAP
2.0
2.5
3.0
4.0
5.0
6.0 7.0
8.0
10.0
12.0
16
RATING
8.0
9.0
10.0
12.0
14.0 15.0 16.0 17.5
20.0
20.0
20.0
INSTANTANEOUS
UNIT
The
instantaneous
unit
has
a double—wound
coil
for
operation
on
either
one
of
two
ranges.
Any
setting
obtained
in
the
lower
range
(series
connected)
is
doubled,
within
±10%,
when
the
unit
is
connected
for
high—range
operation
(parallel
connected).
The
instantaneous
unit
has
a
continuous
rating
of
1.5 times
minimum
setting
or
25
amperes, whichever
is
smaller.
Example:
the
2.0—16.0
ampere
instantaneous
unit,
when
set
on
the
low
range
(2.0—
8.0
amperes) has
a
continuous
rating
of
3.0
amperes,
and
when
connected
for
high—range
operation
(4.0—16.0
amperes)
has
a
continuous
rating
of
6.0
amperes.
The
continuous
and
one—second
ratings
for
the
instantaneous
unit
are
shown
in
Table
VI.
6

GEK-34053
TABLE
VI
RANGE
CONNECTIONS
CONTINUOUS
I-
ONE
K
if
RATING
SECOND
0.5
-
4.00
0.5
-
2.00
S
0.75 25.0
625
1.0
-
4.00
P
1.5
50.0 2,500
2.0
-
16.0
2.0
-
8.00
S
3.0
130.0
16,900
4.0
-
16.00
P
6.0
260.0 67,600
10.0
-
80.0
10.0
-
40.0
S
15.0
400.0
160,000
20.0
-
80.0
P
25.0 600.0
360,000
20.0
-
160.0
20.0
-
80.0
S
25.0
600.0
360,000
40.0
-
160.0
P
25.0
600.0
360,000
I
Higher
currents
may
be
applied
for
shorter
lengths
of time
in
accordance
with
the
formula
K
1=!—
‘I,
where
T
is
the time,
in
seconds,
that
the
current
flows.
It
S
Series
connected,
P
=
Parallel
connected
TARGET
AND
SEAL-IN
UNIT
Ratings
for
the
target
and
seal—in
unit
are
shown
in
Table
VII
TABLE
VII
TAP
0.2
2.0
D.C.
Resistance
±10%
(ohms)
7
0.13
Mi
Operating
(amperes)
+0
-
25%
0.2
2.0
Carry
Continuously
(amperes)
0.3
3.0
Carry
30
Amps
for
(sec.)
0.03
4.0
Carry
10
Amps
for
(sec.)
0.25 30.0
60
Hz
Impedance
(ohms)
52.0
0.53
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
of
the
target
and
seal—in
coils
of
the
protective
relay.
CONTACTS
The
current—closing
rating
of
the
contacts
is
30
amperes
for
voltages
not exceeding
250
volts.
The
current—carrying
rating
is
limited
by the
ratings
of
the
seal—in
unit.
7

GEK-34053
BURDENS
Burdens
for the
time—overcurrent
unit are
given in Table VIII.
TABLE
VIII
RANGE
HZ MIN.
BURDENS
AT MIN.
BURDENS IN
V.A. AT
5
AMPS
TAP PICKUP
MIN. TAP
OHMS (1)
CALCULATED
FROM
IMPEDANCE AT MIN.
PICKUP
(121)
R Z
3 10 20.0
TIMES
TIMES TIMES
PICK- PICK- PICK
UP
UP UP
0.5
- 0.4 60 0.5 5.60 21.0 22.0
10.80 5.00 3.66
550.0
2.0 - 15.0 60
2.0
0.37 1.44 1.45
0.65
0.32 0.24 36.3
NOTE: The impedance values
given are
those for
the minimum
tap
of
each relay. The impedance for other taps
at
pick
up
current (tap rating) varies
inversely (approximately) as
the
square of the
tap rating.
For
examp1e for
a
relay
with
0.5-4.0
amp range, the impedance
of the 0.5 amp tap
is given
as
22.0 ohms. The
impedance of the
2.0 amp
tap
at 2.0 amperes is
(.5/2)2
x 22
= 1.37
ohm.
The instantaneous
unit burdens are listed
in
Table
IX.
TABLE IX
BURDENS AT MIN. BURDENS IN
RANGE
tCON-
MIN.
PICKUP
MIN. TAP OHMS (1)
60
HZ
NEC- TAP
___________________ __________________
RELAYS TIONS AMPS R Z
3
10 20.0 V.A. AT
5AMPS
ONLY
OHMS OHMS OHMS TIMES TIMES TIMES CALCULATED
FROM
(AMPS) PICK PICK PICK
IMPEDANCE
AT MIN.
UP
UP UP PICKUP
(12Z)
O
5—4
0
LOW
0.5
12.7
11.5 17.1 9.6
8.7
8.2 427.5
HIGH
1.0 3.18 2.87
4.28 2.40 2.18 2.04 107.0
2 0-16 0
LOW 2.0 0.76 0.72 1.05 0.59 0.53
0.50
26.25
HIGH
4.0 0.189
0.180 0.261 0.147 0.133 0.125
6.63
10
0-80 0
LOW
10.0
0.042 0.029 0.051
0.029 0.026 0.024 1.28
HIGH 20.0
0.010 0.007 0.013 0.007
0.007
0.006 0.33
20.0-160.0
LOW 20.0
0.015 0.008
0.017
0.010
0.009
0.008
0.43
HIGH
40.0
0.004
0.002
0.004
0.002 0.002
0.002
0.10
j-
Low means two
windings
connected
in
series.
High means two
windings
connected
in parallel.
See
Internal-Connections
diagram
for
additional
information.
8

GEK-34053
CHARACTERI
STICS
Pickup
of
these
relays
is
defined
as
the
current
required
to
close
the
contacts
from
the
0.5
time—dial
position.
The
pickup
value
of
the
IAC51
relays is
within
3%
of
tap
value.
The
setting
of the
time
dial
determines
the
length
of
time
the
unit requires
to
close
its
contacts
when
the
current
reaches
the
predetermined
value.
The
contacts
are
just
closed
when
the
dial
is
set
at
zero.
When
the
dial
is
set
at 10,
the
disk
must
travel
the
maximum
distance
to
close
the
contacts;
this
gives
the
maximum
time
setting.
The
unit
resets
at
90%
of
the
minimum
closing
value
of
current.
The
time
to
reset
to the
No.
10
time—dial
position
when
the
current
is
reduced
to zero
is
approximately
7
seconds.
Figure
9 shows
the
50
Hz
and
Figure
10
shows
the
60
Hz
time/current
characteristics
for
relay
types
IAC51
and
1AC52.
The
time/current
curve
for
the
instantaneous
unit
is
shown on
Figure
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
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
Sales
Office.
Reasonable
care
should
be
exercised
in
unpacking
the
relay
in
order
that
none
of
the
parts
are
injured
nor
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.
ACCEPTANCE
TESTS
Immediately
upon
receipt
of
the
relay
an
INSPECTION
AND
ACCEPTANCE
TEST
should
be made
to
make
sure
that
no
damage
has
been
sustained
in
shipment
and
that
the
relay
calibrations
have
not
been
disturbed.
If
the examination
or
test
indicates
that
readjustment
is
necessary,
refer
to the
section
on
SERVICING.
These
tests
may
be
performed as
part
of
the
installation
or
as
acceptance
tests,
at the
discretion
of
the
user.
Since
most
operating
companies
use
different
procedures
for
acceptance
and
for
installation
tests,
the
following
section
includes
all
applicable
tests
that
may
be
performed
on
these
relays.
9

GEK-34053
VISUAL
INSPECTION
Check
the
nameplate
stamping
to
make
sure
that
the
model
number
and
rating
of
the
relay
agree
with
the
requisition.
Remove
the
relay
from
its
case
and
check
that
there
are
no
broken
or
cracked
molded
parts
or
other
signs
of
physical
damage,
and
that
all
screws
are
tight.
MECHANICAL
INSPECTION
1.
There
should
be
no
noticeable
friction
when
the
disk
is
rotated
slowly
clockwise.
The
disk
should
return
by
itself
to
its
rest
position.
2.
Make
sure
the
control
spring
is
not
deformed,
nor
its
convolutions
tangled
or
touching.
3.
The
armature
and
contacts
of
the
seal—in
unit,
as
well
as
the
armature
and
contacts
of
the
instantaneous
unit,
should
move
freely
when
operated
by
hand;
there
should
be
at
least
1/32”
wipe
on
the
seal—in
contacts.
4.
The
targets
in
the
seal—in
unit
and
in
the
instantaneous
unit
must
come
into
view
and
latch
when
the
armatures
are
operated
by
hand,
and
should
unlatch
when
the
target
release
lever
is
operated.
5.
Make
sure
that
the
fingers
and
shorting
bars
agree
with
the
internal—connections
diagram.
CAUTION
Every
circuit
in
the
drawout
case
has
an
auxiliary
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
Current
Transformer
(CT)
secondary
circuits
from
being
opened.
See
Figure
1.
ELECTRICAL
TESTS
DRAWOUT
RELAYS,
GENERAL
Since
all
drawout
relays
in
service
operate
in
their
cases,
it
is
recommended
that
they
be
tested
in
their
cases
or
an
equivalent
steel
case.
In
this
way,
any
magnetic
effects
of
the
enclosure
will
be
accurately
duplicated
during
testing.
A
relay
may
be
tested
without
removing
it
from
the
panel
by
using
a
12XLA13A
test
plug.
This
plug
makes
connections
only with
the
relay
and
does
not
disturb
any
shoring bars
in
the
case.
The
12XLA12A
test
plug
may
also
be
used.
Although
this
test
plug
allows
greater
testing
flexibility,
it
requires
C.T.
shorting
jumpers
and
the
exercise
of
greater
care,
since
connections
are
made
to
both
the
relay
and
the
external
circuitry.
10