GE IAC77A User manual

GEK
-
34055
F
INSTRUCTIONS
TIME
OVERCURRENT
RELAYS
TYPES
IAC
77
A
FORM
800
AND
UP
IAC
77
B
FORM
800
AND
UP
IAC
78
A
FORM
800
AND
UP
IAC
78
B
FORM
800
AND
UP
GENERAL
ELECTRIC
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GEK
-
34055
TABLE
OF
CONTENTS
PAGE
DESCRIPTION
APPLICATION
CONSTRUCTION
RATINGS
3
4
4
5
TIME
-
OVERCURRENT
UNIT
.
INSTANTANEOUS
UNIT
. .
TARGET
AND
SEAL
-
IN
UNIT
CONTACTS
5
6
7
8
BURDENS
CHARACTERISTICS
RECEIVING
,
HANDLING
,
AND
STORAGE
..
. .
ACCEPTANCE TESTS
VISUAL
INSPECTION
MECHANICAL
INSPECTION
ELECTRICAL TESTS
DRAWOUT
RELAYS
GENERAL
POWER
REQUIREMENTS
GENERAL
..
.
TIME
-
OVERCURRENT
UNIT
PICKUP TEST
TIME
TEST
INSTANTANEOUS
UNIT
SETTING
THE
INSTANTANEOUS
UNIT
PICK
UP
TESTS
TARGET
AND
SEAL
-
IN
UNIT
. . .
.
PICK
-
UP
AND
DROPOUT
TEST
.
.
8
9
9
10
.
10
10
11
11
11
11
12
12
.
12
12
13
13
13
14
INSTALLATION
TIME
-
OVERCURRENT
UNIT
TARGET
AND
SEAL
-
IN
UNIT
INSTANTANEOUS
UNIT
.
PERIODIC
CHECKS
AND
ROUTINE MAINTENANCE
TIME
OVERCURRENT
UNIT
INSTANTANEOUS
UNIT
,
TARGET
AND
SEAL
-
IN
UNIT
CONTACT CLEANING
SYSTEM
TEST
SERVICING
,
TIME
-
OVERCURRENT
UNIT
TIME
TESTS
INSTANTANEOUS
UNIT
TARGET
AND
SEAL
-
IN
UNIT
RENEWAL
PARTS
14
14
14
15
15
15
15
15
15
16
16
17
18
18
18
(
Cover
photo
8041299
)
2
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GEK
-
34055
TIME
OVERCURRENT
RELAYS
TYPES
IAC
77
A
,
77
B
,
78
A
,
78
B
FORM
800
and
UP
DESCRIPTION
nype
IAC
77
and
IAC
78
relays
are
single
-
phase
,
current
-
operated
,
AC
de
ices
with
extremely
inverse
time
/
current
characteristics
.
They
can
be
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
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
.
1
.
A
standard
SI
case
is
used
to
mount
each
relay
,
mounting
dimensions
of
this
case
are
shown
in
Figures
11
and
12
.
The
outline
and
The
basic
differences
between
the
relays
covered
by
these
instructions
are
noted
in
the
following
Table
I
.
TABLE
I
INSTANTANEOUS
CONTACT
CIRCUITS
INTERNAL
CONNECTIONS
TYPE
UNIT
IAC
77
A
IAC
77
B
IAC
78
A
IAC
78
B
1
FIGURE
4
FIGURE
5
FIGURE
6
FIGURE
7
NO
1
YES
2
NO
YES
2
These
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
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GEK
-
34055
APPLICATION
The
extremely
inverse
time
/
current
characteristics
make
the
IAC
77
IAC
78
relays
particularly
well
suited
for
the
protection
of
In
such
applications
,
because
the
power
fuses
possible
to
obtain
and
primary
distribution
circuits
.
relay
characteristics
closely
parallel
those
of
the
normally
employed
in
these
circuits
,
it
is
selective
fault
protection
with
a
minimum
time
delay
.
The
unique
time
-
current
characteristics
of
these
relays
also
make
them
well
suited
for
picking
up
cold
loads
.
For
any
given
cold
load
pick
up
capability
,
the
resulting
setting
will
provide
faster
protection
at
high
fault
currents
with
the
extremely
inverse
relay
than
with
less
inverse
devices
.
The
general
practice
is
to
use
a
set
of
three
relays
for
interphase
faults
.
A
separate
relay
,
residually
connected
,
can
be
utilized
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
applying
these
relays
are
shown
in
Figures
14
and
15
.
In
the
application
of
IAC
77
and
IAC
78
relays
with
automatic
reclosing
devices
,
the
reset
time
should
be
considered
.
The
reset
time
of
all
relays
covered
by
these
instructions
is
approximately
60
seconds
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
"
downstream
"
relays
,
a
coordination
time
of
from
0.25
to
.
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
time
is
set
by
test
at
the
current
level
in
question
,
the
safety
factor
may
be
reduced
from
0.17
to
0.07
second
.
Then
with
relay
overtravel
of
.
10
second
,
if
the
"
downstream
"
breaker
time
is
5
cycles
(
0.08
second
)
,
a
minimum
of
0.25
second
could
be
allowed
for
coordination
.
If
the
downstream
devices
are
fuses
rather
than
circuit
breakers
,
then
the
maximum
clearing
time
of
the
fuse
should
be
used
and
the
time
allowed
for
breaker
-
clearing
time
should
be
omitted
.
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
wattmetric
-
type
current
-
operating
element
.
This
is
similar
to
the
standard
element
as
used
in
watthour
meters
,
except
the
actuating
coils
above
and
below
the
operating
disk
are
connected
in
series
.
A
capacitor
and
variable
resistor
connected
in
series
with
the
inner
coil
on
the
upper
laminated
structure
makes
up
the
phase
-
shifting
circuit
.
contact
,
which
completes
the
trip
or
alarm
circuit
,
is
restrained
by
a
spiral
spring
to
give
proper
contact
-
closing
The
disk
shaft
carries
the
moving
The
disk
shaft
4
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GEK
-
34055
and
its
motion
is
retarded
by
a
permanent
magnet
acting
on
current
,
the
disk
to
give
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
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
,
instantaneous
unit
picks
up
it
raises
a
target
,
which
latches
up
and
remains
exposed
until
it
is
released
,
the
target
of
the
seal
-
in
unit
also
releases
the
target
of
the
instantaneous
unit
.
When
the
The
same
button
that
releases
RATINGS
TIME
-
OVERCURRENT
UNIT
Ratings
of
the
time
-
overcurrent
unit
are
given
in
Table
II
.
TABLE
II
PICK
UP
RANGE
.
AMPERES
MAIN
(
TIME
)
FREQUENCY
CYCLES
INSTANTANEOUS
RELAY
UNIT
UNIT
0.5
-
4.0
1.5
-
12.0
2.0
-
15.0
IAC
77
A
and
IAC
78
A
50
60
0.5
-
4.0
1.5
-
12.0
2.0
-
15.0
0.5
-
4.0
2.0
-
16.0
10.0
-
80.0
20.0
-
160.0
IAC
77
B
and
IAC
78
B
50
60
Available
taps
of
the
t
ime
-
overcur
rent
unit
are
shown
on
Table
III
.
TABLE
III
TAPS
AVAILABLE
(
AMPERES
)
RANGE
,
AMPERES
0.5
,
0.6
,
0.7
,
0.8
1.0
,
1.2
,
1.5
,
2.0
,
2.5
,
3.0
,
4.0
0.5
-
4.0
1.5
-
12.0
1.5
,
2.0
,
2.5
,
3.0
,
4.0
,
5.0
,
6.0
,
7.0
,
8.0
,
10.0
,
12.0
2.0
-
15.0
2.0
,
2.5
,
3.0
,
4.0
,
5.0
,
6.0
,
7.0
,
8.0
,
10.0
,
12.0
,
15.0
The
one
-
second
thermal
ratings
are
listed
in
Table
IV
.
5
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GEK
-
34055
TABLE
IV
TIME
OVERCURRENT
UNIT
(
AMPS
)
ONE
SECOND
RATING
(
AMPS
)
K
0.5
-
4.0
125.0
15
,
625
1.5
-
12.0
260.0
67
,
600
2.0
-
15.0
260.0
67
,
600
For
ratings
of
less
than
one
second
,
the
rating
may
be
calculated
according
to
the
formula
/
=
where
T
is
the
time
,
in
seconds
,
that
the
current
flows
.
The
continuous
ratings
of
the
time
-
overcurrent
units
are
shown
in
Table
V
.
TABLE
V
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
3.5
3.7
4.0
4.5
5.0
5.5
6.0
7.0
8.0
9.0
10.0
1.5
-
12.0
AMPRANGE
TAP
1.5
2.0
2.5
3.0
4.0
5.0
6.0
7.0
8.0
10.0 12.0
RATING
9.5
10.5 11.5
12.5
14.0
15.5
17.0 18.0 19.0
20.0 20.0
2.0
-
15.0
AMPRANGE
TAP
2.0
2.5
3.0
4.0
5.0
6.0
7.0
8.0
10.0
12.0
15.0
RATING
10.0
11.0
12.0
13.0
15.0
17.0
18.0 19.0
20.0
20.0
20.0
INSTANTANEOUS
UNIT
The
instantaneous
unit
has
a
double
-
wound
coil
for
operation
on
Any
setting
obtained
in
the
lower
range
either
one
of
two
ranges
.
(
series
connected
)
is
doubled
,
within
±
3
%
,
when
the
unit
is
connected
for
high
-
range
operation
(
parallel
connected
)
.
6
Courtesy of NationalSwitchgear.com

GEK
-
34055
The
instantaneous unit
has
a
continuous
rating
of
minimum
setting
or
25
amperes
,
whichever
is
smaller
.
2.0
-
16.0
ampere
instantaneous
unit
,
8.0
amperes
)
has
a
continuous
rating
of
3.0
connected for
high
-
range
operation
(
4.0
-
16.0
continuous
rating
of
6.0
amperes
.
ratings
for
the
instantaneous
unit
are
shown
in
Table
VI
.
times
The
1.5
Example
:
when
set
on
the
low
range
(
2.0
-
amperes
,
and
when
amperes
)
has
a
The
continuous
and
one
-
second
TABLE
VI
RANGE
CONNECT
-
CONTINUOUS
RATING
t
ONE
SECOND
K
IONS
tt
0.5
-
4.0 0.5
2.0
S
4.0
P
0.75
25.0
625
1.0
1.5
50.0
2
,
500
2.0
-
16.0
2.0
130.0
260.0
16
,
900
67
,
600
8.0
S
16.0
P
3.0
4.0
6.0
10.0
-
80.0
10.0
-
40.0
S
20.0
-
80.0
P
15.0
160
,
000
360
,
000
400.0
600.0 25.0
20.0
-
160.0
20.0
-
80.0
S
40.0
-
160.0
P
25.0 600.0
600.0
360
,
000
360
,
000
25.0
t
Higher
currents
may
be
applied
for
shorter
lengths
of
time
in
accordance
with
the
formula
K
/
=
V
-
7
where
T
is
the
time
,
in
seconds
,
that the
current
flows
.
tt
S
Series
connected
,
P
-
Parallel
connected
TARGET
AND
SEAL
-
IN
UNIT
Ratings
for
the
target
seal
-
in
unit
are
shown
in
Table
VII
.
TABLE
VII
TAP
0.2
2.0
D
.
C
.
Resistance
±
10
%
(
ohms
)
0.13
7
MIN
.
Operating
(
amperes
)
+
0
-
25
%
2.0
0.2
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
7
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GEK
-
34055
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
.
BURDENS
Burdens
for
the
time
-
overcur
rent
unit
are
given
in
Table
VIII
.
TABLE
VIII
BURDENS
AT
MIN
.
PICKUP
MIN
.
TAP
BURDENS
IN
OHMS
(
Z
)
V
.
A
.
AT
5
AMPS
3
10
20.0
CALCULATED
FROM
IMPEDANCE
AT
MIN
.
PICKUP
(
l
2
z
)
RANGE
HZ
MIN
.
R
Jx
Z
TAP
TIMES
TIMES
TIMES
PICK
-
PICK
-
PICK
-
UP UP
UP
0.5
-
0.4
60
0.5
0.80
1.38
1.60 1.60
1.60 1.60
40
1.5
-
12.0
60
1.5
0.085
.
147
0.17
0.17 0.17 0.17
4.25
2.0
-
15.0
60
2.0
0.05
0.086
0.099
0.10 0.10 0.10
2.5
The
impedance
values
given
are
those
for
the
minimum
tap
of
each
relay
.
cur
rent
NOTE
:
The
impedance
for
other
taps
at
(
tap
rating
)
varies
inversely
For
4.0
amp
range
,
the
1.60
ohms
.
pick
-
up
(
approximately
)
as
the
square
of
the
tap
rating
,
example
,
for
a
relay
with
0.5
impedance
of
the
0.5
amp
tap
is
given
as
The
impedance
of
the
2.0
amp
tap
at
2.0
amperes
is
(
.
5
/
2
)
2
x
1.6
or
0.10
ohm
.
8
Courtesy of NationalSwitchgear.com

GEK
-
34055
The
instantaneous
unit
burdens
are
listed
in
Table
IX
.
TABLE
IX
BURDENS
AT
MIN
.
PICKUP
MIN
.
TAP
BURDENS
IN
OHMS
(
Z
)
RANGE
60
HZ
RELAYS
CON
-
MIN
.
NEC
-
TAP
TIONS
AMPS
R
Jx
Z
3
10
20.0
OHMS OHMS
OHMS
TIMES
TIMES
TIMES
PICK PICK
PICK
V
.
A
.
AT
5
AMPS
CALCULATED
FROM
IMPEDANCE
AT
MIN
.
PICKUP
(
I
2
Z
)
ONLY
t
(
AMPS
)
UP
UP
UP
0.5
12.7
11.5
17.1
1.0
3.18
2.87
4.28
LOW
9.6
8.7
8.2
2.40
2.18
2.04
427.5
107.0
0.5
-
4.0
HIGH
1.05
LOW
2.0
0.76
0.72
0.189
0.180
0.261
0.147
0.133
0.125
0.59
0.53
0.50
26.25
2.0
-
16.0
HIGH
4.0
6.63
10.0
LOW
0.042
0.029
0.051
0.029
0.026
0.024
0.010
0.007
0.013
0.007
0.007
0.006
1.28
10.0
-
80.0
HIGH
20.0
0.33
0.015
0.008
0.017
0.010
0.009
0.008
0.004
0.002
0.004
0.002
0.002
0.002
LOW
20.0
0.43
20.0
-
160.0
HIGH
40.0
0.10
t
Low
means
two
windings
connected
in
series
.
High
means
two
windings
connected
in
parallel
.
See
Internal
-
Connections
diagram
for
additional
information
.
CHARACTERISTICS
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
IAC
77
relays
is
within
3
%
of
the
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
85
%
of
the
minimum
closing
value
of
current
.
Figure
9
shows
the
50
-
Hz
and
Figure
10
shows
the
60
-
Hz
Time
/
Current
Characteristics
for
Relay
types
IAC
77
and
IAC
78
.
The
time
to
reset
to
the
10
time
-
dial
position
when
the
current
is
reduced
to
zero
is
approximately
57
seconds
.
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
9
Courtesy of NationalSwitchgear.com

GEK
-
34055
sustained
in
transit
,
handling
is
evident
,
transportation
company
and
promptly
notify
Electric
Sales
Office
.
If
injury
or
damage
resulting
from
rough
file
a
damage
claim
at
once
with
the
the
nearest
General
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
,
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
.
Since
most
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
the
screws
are
tight
.
MECHANICAL
INSPECTION
There
should
be
no
noticeable
friction
when
the
disk
is
rotated
slowly
clockwise
.
The
disk
should
return
by
itself
to
its
rest
position
.
1
.
Make
sure
the
control
spring
is
not
deformed
,
nor
its
convolutions
tangled
or
touching
.
2
.
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
.
3
.
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
.
10
Courtesy of NationalSwitchgear.com