GE IFC51AD User manual
GEK
-
49827
OVERCURRENT
RELAYS
TYPES
IFC
51
AD
and
51
BD
IFC
53
AD
and
53
BD
IFC
77
AD
and
77
BD
INTRODUCTION
These
instructions
plus
those
in
the
included
book
,
GEK
-
45375
,
form
the
instructions
for
these
relays
.
DESCRIPTION
The
Types
IFC
51
AD
,
IFC
53
AD
and
IFC
77
AD
covered
by
these
instructions
are
similar
respectively
to
the
IFC
51
A
,
IFC
53
A
and
IFC
77
A
in
the
included
instructions
except
that
the
target
seal
-
in
units
have
two
elec
-
trically
separate
contacts
.
The
Types
IFC
51
BD
,
IFC
53
BD
and
IFC
77
BD
are
similar
respectively
to
the
IFC
51
B
,
IFC
53
B
and
IFC
77
B
except
that
each
target
seal
-
in
and
instantaneous
unit
has
two
electrically
separate
contacts
.
The
internal
connections
are
included
in
these
instructions
as
tabulated
below
:
Types
Figure
IFC
51
AD
,
-
53
AD
,
-
77
AD
IFC
51
BD
,
-
53
BD
,
-
77
BD
1
2
APPLICATION
The
application
areas
of
these
relays
are
the
same
in
all
respects
to
those
covered
by
the
APPLICATION
section
in
the
included
instructions
,
GEK
-
45375
.
Note
that
the
second
contact
on
the
seal
-
in
unit
,
and
the
instantaneous
overcurrent
unit
when
present
,
is
intended
for
local
alarm
and
/
or
remote
indication
as
shown
on
the
typical
external
connections
in
Figure
3
of
these
instructions
.
All
other
sections
of
the
included
book
,
GEK
-
45375
,
also
apply
to
these
relays
.
These
instructions
do
not
purport
to
cover
all
details
or
variations
in
equipment
nor
to
provide
for
every
possible
contingency
to
be
met
in
connection
with
installation
,
operation
or
maintenance
.
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
.
Should
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
Courtesy of NationalSwitchgear.com
GEK
-
49827
T
£
SI
INST
.
to
U
INDUCTION
UNIT
T
$
SI
—
INST
.
INST
.
O
CUD
L
H
\
1
/
v
\
K
M
/
Y
*
V
*
4
\
1
/
M
/
V
V
V
*
V
*
Y
*
V
*
V
*
o
c
o
c
2
12
6
14
O
o
o
o
o
3
1
5
11
13
INSTANTANEOUS
SETTINGS
:
SET
LINK
TO
"
Hw
FOR
HIGH
RANGE
AND
TO
"
L
"
P
0
R
LOW
RANGE
.
LINK
SHOWN
IN
HIGH
RANGE
POSITION
.
-
K
-
=
SHORT
FINGER
FIG
.
2
(
0208
A
8515
-
1
)
INTERNAL
CONNECTIONS
FOR
RELAY
TYPES
IFC
51
BD
,
IFC
53
BD
AND
IFC
77
BD
-
FRONT
VIEW
.
5
Courtesy of NationalSwitchgear.com
GEK
-
49827
A
-
C
BUS
50
-
1
51
~
i
Ar
Vr
5
o
50
-
2
51
-
2
-
^
F
-
V
50
-
3
51
-
3
A
5
\
Jluf
51
-
N
50
-
N
\
5
6
NOTE
:
50
DEVICr
ER
:
•
2
'
IT
'
-
N
.
Y
IN
IFC
52
B
,
-
54
B
AND
—
78
B
52
IT
r
FEEDER
(
+
)
D
-
C
TRIP
BUS
(
+
)
ALARM
BUS
S
1
^
51
-
1
j
TSI
n
151
-
1
*
13
*
51
-
2
51
-
3
51
-
N
JT
5
jTl
1
hQ
±
50
±
7
~
ST
j
5
tl
T
50
-
1
SAME
AS
PHASE
1
T
50
-
1
12
T
14
'
2
3
ALARM
JR
REMOTE
INDICATION
52
*
PHASES
2
£
3
AND
NEUTRAL
SAME
AS
PHASE
~
1
TC
(
-
)
FIG
.
3
(
0275
AI
903
-
0
)
EXTERNAL
CONNECTIONS
OF
FOUR
IFC
RELAYS
USED
FOR
MULTI
-
PHASE
AND
PHASE
TO
GROUND
FAULT
PROTECTION
OF
A
3
-
PHASE
CIRCUIT
.
6
Courtesy of NationalSwitchgear.com
GEK
-
45375
CONTENTS
DESCRIPTION
3
APPLICATION
3
CONSTRUCTION
5
6
RATINGS
6
TIME
OVERCURRENT
UNIT
HIGH
-
SEISMIC
INSTANTANEOUS
UNIT
HIGH
-
SEISMIC
TARGET
AND
SEAL
-
IN
UNIT
CONTACTS
7
8
8
BURDENS
9
CHARACTERISTICS
TIME
OVERCURRENT
UNIT
HIGH
-
SEISMIC
INSTANTANEOUS
UNIT
HIGH
-
SEISMIC
TARGET
AND
SEAL
-
IN
UNIT
10
10
10
10
RECEIVING
,
HANDLING
AND
STORAGE
10
ACCEPTANCE
TESTS
VISUAL
INSPECTION
MECHANICAL
INSPECTION
DRAWOUT
RELAY
TESTING
GENERAL
POWER
REQUIREMENTS
TIME
OVERCURRENT
UNIT
HIGH
-
SEISMIC
INSTANTANEOUS
UNIT
HIGH
-
SEISMIC
TARGET
AND
SEAL
-
IN
UNIT
11
11
11
12
12
12
13
14
INSTALLATION
INSTALLATION
TESTS
15
15
PERIODIC
CHECKS
AND
ROUTINE
MAINTENANCE
.
.
TIME
OVERCURRENT
UNIT
HIGH
-
SEISMIC
INSTANTANEOUS
UNIT
HIGH
-
SEISMIC
TARGET
AND
SEAL
-
IN
UNIT
CONTACT
CLEANING
COVER
CLEANING
SYSTEM
TEST
16
16
16
16
16
17
17
SERVICING
17
TIME
OVERCURRENT
UNIT
HIGH
-
SEISMIC
INSTANTANEOUS
UNIT
HIGH
-
SEISMIC
TARGET
AND
SEAL
-
IN
UNIT
17
19
19
RENEWAL
PARTS
20
LIST
OF
FIGURES
40
-
2
-
Courtesy of NationalSwitchgear.com
GEK
-
45375
TIKE
OVERCURRENT
RELAYS
TYPES
IFC
51
A
and
51
B
IFC
43
A
and
53
B
IFC
77
A
and
77
B
DESCRIPTION
The
type
IFC
relays
covered
by
these
instructions
are
extended
range
,
single
phase
,
time
overcurrent
relays
,
available
are
as
follows
:
The
various
time
-
current
characteristics
IFC
51
A
,
IFC
51
B
-
Inverse
time
IFC
53
A
,
IFC
53
B
-
Very
inverse
time
IFC
77
A
,
IFC
77
B
-
Extremely
inverse
time
The
IFC
51
B
,
53
B
and
77
B
relays
also
include
a
hinged
-
armature
instantaneous
overcurrent
unit
,
which
provides
instantaneous
tripping
at
high
current
levels
.
The
instantaneous
unit
is
not
included
in
the
IFC
51
A
,
53
A
or
77
A
relays
.
Both
the
time
overcurrent
unit
and
the
instantaneous
overcurrent
unit
Each
relay
is
are
described
in
detail
in
the
section
on
CONSTRUCTION
,
equipped
with
a
dual
-
rated
target
and
seal
-
in
unit
.
When
semi
flush
mounted
on
a
suitable
panel
,
these
relays
have
a
high
seismic
capability
,
including
both
the
target
seal
-
in
unit
and
the
instantaneous
overcurrent
unit
when
it
is
supplied
.
Also
,
these
relays
are
recognized
under
the
Components
Program
of
Underwriters
Laboratories
,
Inc
.
The
relay
is
mounted
in
a
size
Cl
drawout
case
of
molded
construction
.
The
outline
and
panel
drilling
are
shown
in
Figures
23
and
24
.
The
relay
internal
connections
are
shown
in
Figure
4
for
the
IFC
51
A
,
53
A
and
77
A
,
and
in
Figure
5
for
the
IFC
51
B
,
53
B
and
77
B
.
APPLICATION
Time
overcurrent
relays
are
used
extensively
for
the
protection
of
utility
and
industrial
power
distribution
systems
and
frequently
for
overload
backup
protection
at
other
locations
.
The
EXTREMELY
INVERSE
time
charactersisties
,
Figures
10
and
22
,
of
the
IFC
77
A
and
77
B
relays
are
designed
primarily
for
use
where
they
are
required
to
coordinate
rather
closely
with
power
fuses
,
distribution
cutouts
and
reclosers
.
They
also
provide
maximum
tolerance
to
allow
for
cold
load
pickup
such
as
results
from
an
extended
service
outage
,
which
results
in
a
heavy
accumulation
of
loads
of
automatically
controlled
devices
such
as
refrigerators
,
water
heaters
,
water
pumps
,
oil
burners
,
etc
.
Such
load
accumulations
often
produce
inrush
currents
considerably
in
excess
of
feeder
full
load
current
for
a
short
time
after
the
feeder
is
energized
.
These
instructions
do
not
purport
to
cover
all
details
or
variations
in
equipment
nor
to
provide
for
every
possible
contingency
to
be
met
in
connection
with
installation
,
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
reguired
the
products
described
herein
meet
applicable
ANSI
,
but
no
such
assurance
is
given
with
respect
to
local
codes
and
ordinances
because
they
vary
greatly
.
Should
operation
or
maintenance
.
IEEE
and
NEHA
standards
/
-
3
-
Courtesy of NationalSwitchgear.com
GEK
-
45375
The
EXTREMELY
INVERSE
time
characteristic
often
permits
successful
pickup
of
these
loads
and
at
the
same
time
provides
adequate
fault
protection
.
The
VERY
INVERSE
time
characteristics
,
Figures
7
and
21
,
of
the
IFC
53
A
and
53
B
relays
are
likely
to
provide
faster
overall
protection
in
applications
where
the
available
fault
current
magnitude
remains
fairly
constant
due
to
a
relatively
constant
generating
capacity
.
The
variation
in
the
magnitude
of
fault
current
through
the
relay
is
therefore
mainly
dependent
upon
the
location
of
the
fault
with
respect
to
the
relay
.
The
INVERSE
time
overcurrent
characteristics
,
Figures
6
and
20
,
of
the
IFC
51
A
and
51
B
relays
tend
to
make
the
relay
operating
time
less
dependent
upon
the
magnitude
of
the
fault
current
than
in
the
case
of
VERY
INVERSE
and
EXTREMELY
INVERSE
devices
.
faster
overall
protection
in
applications
where
the
available
fault
current
magnitudes
vary
significantly
as
a
result
of
frequent
changes
in
the
source
impedance
due
to
system
loading
and
switching
.
For
this
reason
,
INVERSE
type
relays
are
likely
to
provide
The
usual
application
of
these
relays
requires
three
relays
for
multiphase
fault
protection
,
one
per
phase
,
and
a
separate
relay
residually
connected
for
single
-
phase
-
to
-
ground
faults
.
Typical
external
connections
for
this
appli
-
cation
are
shown
in
Figure
9
.
Use
of
a
separate
ground
relay
is
advantageous
because
it
can
be
set
to
provide
more
sensitive
protection
against
ground
faults
.
In
the
application
of
these
relays
with
downstream
automatic
reclosing
devices
,
the
relay
reset
time
should
be
considered
.
This
is
the
time
required
for
the
relay
to
go
from
the
contacts
-
fully
-
closed
position
to
the
fully
-
open
position
when
set
at
the
number
10
time
dial
.
At
lower
time
dial
settings
the
reset
times
are
proportionately
lower
.
The
reset
time
of
all
VERY
INVERSE
and
EXTREMELY
INVERSE
relays
is
approximately
60
seconds
.
The
reset
time
of
all
INVERSE
relays
covered
by
these
instructions
is
approximately
12
seconds
.
When
setting
these
relays
to
coordinate
with
downstream
relays
,
a
coordination
time
of
from
0.25
to
0.40
seconds
is
generally
allowed
,
depending
on
the
clearing
time
of
the
breaker
involved
and
how
accurately
the
relay
time
can
be
estimated
.
These
coordination
times
include
,
in
addition
to
breaker
clearing
time
,
0.10
seconds
for
relay
overtravel
and
0.17
seconds
for
safety
factor
.
For
example
,
if
the
breaker
clearing
time
is
0.13
seconds
(
8
cycles
)
,
the
coordination
time
would
be
0.40
seconds
(
0.13
+
0.10
+
0.17
)
.
If
the
relay
time
is
set
for
the
specific
current
level
at
the
site
,
and
if
it
has
been
tested
,
the
safety
factor
may
be
reduced
to
0.07
seconds
.
Then
if
the
downstream
breaker
time
is
5
cycles
(
0.08
seconds
)
,
a
minimum
of
0.25
seconds
(
0.08
+
0.10
+
0.07
)
could
be
allowed
for
coordination
.
If
relay
coordination
times
are
marginal
or
impossible
to
obtain
,
use
the
relay
overtravel
curves
of
Figures
10
,
11
or
12
to
refine
the
relay
settings
.
First
determine
the
relay
operating
time
necessary
to
just
match
the
operating
time
of
the
downstream
relay
with
which
coordination
is
desired
.
Determine
the
multiple
of
pickup
and
the
necessary
time
dial
setting
to
provide
this
relay
operating
time
.
Use
the
appropriate
curve
of
Figure
10
,
11
or
12
to
determine
the
overtravel
time
in
percent
of
operating
time
,
and
covert
this
into
real
time
.
Add
this
time
to
the
breaker
time
and
the
safety
factor
time
and
the
original
relay
operating
time
to
determine
the
final
relay
operating
time
.
Set
the
relay
to
this
value
.
-
4
-
Courtesy of NationalSwitchgear.com
GEK
-
45375
Once
the
current
in
the
relay
operating
coil
is
cut
off
,
the
relay
contacts
will
open
in
approximately
6
cycles
(
0.1
second
)
with
normal
adjustment
of
contact
wipe
.
instantaneous
reclosing
schemes
without
risk
of
a
false
retrip
when
the
circuit
breaker
is
reclosed
on
a
circuit
from
which
a
fault
has
just
been
cl
eared
.
This
permits
the
use
of
the
relay
in
conjunction
with
The
instantaneous
overcurrent
unit
present
in
the
IFC
51
B
,
53
B
and
77
B
relays
has
a
transient
overeach
characteristic
as
illustrated
in
Figure
13
.
This
is
the
result
of
the
DC
offset
that
is
usually
present
in
the
line
current
at
the
inception
of
a
fault
.
When
determining
the
pickup
setting
for
this
unit
,
the
transient
overreach
must
be
taken
into
consideration
.
The
percent
transient
overreach
should
be
applied
to
increase
the
calculated
pickup
setting
proportionately
so
that
the
instantaneous
unit
will
not
overreach
a
downstream
device
and
thereby
cause
a
loss
of
coordination
in
the
system
protection
scheme
.
The
operating
time
characteristics
of
this
unit
are
shown
in
Figure
14
.
CONSTRUCTION
The
IFC
induction
disk
relays
consist
of
a
molded
case
,
cover
,
support
structure
assembly
,
and
a
connection
plug
to
make
up
the
electrical
connection
.
See
Cover
Figure
and
Figures
1
,
2
,
3
and
19
.
Figures
2
and
3
show
the
induction
unit
mounted
to
the
molded
support
structure
.
This
disk
is
activated
by
a
current
-
operating
coil
mounted
on
either
a
laminated
EE
-
or
a
U
-
Magnet
.
completes
the
alarm
or
trip
circuit
when
it
touches
a
stationary
contact
.
The
disk
assembly
is
restrained
by
a
spiral
spring
to
give
the
proper
contact
closing
current
.
Its
rotation
is
retarded
by
a
permanent
magnet
mounted
in
a
molded
housing
on
the
support
structure
.
The
disk
and
shaft
assembly
carries
a
moving
contact
,
which
The
drawout
connection
/
test
system
for
the
Cl
case
,
shown
in
Figure
19
,
has
provisions
for
14
connection
points
,
and
a
visible
CT
shorting
bar
located
up
front
.
fingers
in
the
output
contact
circuits
first
,
opened
before
any
other
circuits
are
disconnected
,
fingers
on
the
case
connection
block
engage
the
shorting
bar
(
located
at
the
lower
front
of
the
case
)
to
short
-
circuit
external
current
transformer
secondary
connections
,
shorting
.
The
connection
plug
then
clears
the
current
circuit
contact
fingers
on
the
case
and
finally
those
on
the
relay
support
structure
,
to
de
-
energize
the
drawout
element
completely
.
As
the
connection
plug
is
withdrawn
,
it
clears
the
shorter
contact
Thus
,
the
trip
circuit
is
Next
,
current
circuit
The
window
provides
visual
confirmation
of
CT
There
is
a
High
-
Seismic
target
and
seal
-
in
unit
mounted
on
the
front
to
the
left
of
the
shaft
of
the
time
overcurrent
unit
(
see
Figure
1
)
.
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
reset
button
located
on
the
upper
left
side
of
the
cover
.
-
5
-
Courtesy of NationalSwitchgear.com
GEK
-
45375
The
IFC
"
B
"
model
relays
,
in
addition
to
the
above
,
contain
a
high
-
seismic
instantaneous
unit
(
see
Figure
1
)
.
The
instantaneous
unit
is
a
small
hinged
-
type
unit
which
is
mounted
on
the
front
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
reset
button
that
releases
the
target
seal
-
in
unit
also
releases
the
target
of
the
instantaneous
unit
.
A
magnetic
shield
,
depicted
in
Figure
1
,
is
mounted
to
the
support
structure
of
inverse
and
very
inverse
time
overcurrent
IFC
relays
(
IFC
51
and
IFC
53
)
,
to
eliminate
the
proximity
effect
of
external
magnetic
materials
.
Both
the
High
-
Seismic
target
and
seal
-
in
unit
and
the
High
-
Seismic
instantaneous
unit
have
the
letters
"
Hi
-
G
"
molded
into
their
target
blocks
to
distinguish
them
as
High
-
Seismic
units
.
Seismic
Fragility
Level
exceeds
peak
axial
acceleration
of
log
'
s
(
4
g
ZPA
)
when
tested
using
a
biaxial
multi
-
frequency
input
motion
to
produce
a
Required
Response
Spectrum
(
RRS
)
in
accordance
with
the
IEEE
Proposed
Guide
for
Seismic
Testing
of
Relays
,
P
501
,
May
,
1977
.
RATINGS
The
relays
are
designed
for
operation
in
an
ambient
air
temperature
from
-
20
OC
to
+
55
°
C
.
TIME
OVERCURRENT
UNIT
Ranges
for
the
time
overcurrent
unit
are
shown
in
Table
I
.
TABLE
I
Frequency
(
Hertz
)
Relay
Current
Range
(
Amperes
)
IFC
51
A
&
B
IFC
53
A
&
B
IFC
77
A
&
B
0.5
-
1.0
-
12.0
4.0
50
and
60
The
current
taps
are
selected
with
two
sliding
tap
screws
on
an
alphabetically
labeled
tap
block
.
The
tap
screw
settings
are
as
listed
in
Table
II
,
on
page
20
,
for
each
model
of
relay
and
tap
range
.
The
one
-
second
thermal
ratings
are
listed
in
Table
III
.
-
6
-
Courtesy of NationalSwitchgear.com
GEK
-
45375
TABLE
III
Model
Time
Overcurrent
Unit
(
Amperes
)
One
Second
Rating
Any
Tap
(
Amperes
)
K
16384
4.0
128
0.5
IFC
51
1.0
-
12.0
260
67600
0.5
-
4.0
140
19600
IFC
53
1.0
-
12.0
26
U
67600
0.5
-
4.0
84
7056
IFC
77
1.0
-
12.0
220
48400
Ratings
less
than
one
second
may
be
calculated
according
to
the
formula
I
-
,
/
K
/
T
,
where
T
is
the
time
in
seconds
that
the
current
flows
.
The
continuous
ratings
for
the
time
overcurrent
unit
are
shown
in
Tables
IV
and
V
.
TABLE
IV
0.5
-
4.0
Ampere
Range
Ratings
f
Tap
Model
0.5
0.6
0.7
0.8
1.0
1.2
1.5
2.0
2.5
3.0
4.0
!
l
FC
51
T
FC
53
IFC
77
1.6
1.8
2.0
2.1
2.3
2.7
3.0
3.5
4.0
4.5
5.0
3.8
4.0
4.2
4.4
4.7
5.0
5.3
5.8
6.2
6.6
7.1
2.5
2.7
3.0
3.2
3.6
4.0
4.5
5.2
5.9
6.5
7.5
TABLE
V
1.0
-
12.0
Ampere
Range
Ratings
Tap
Model
1.0
1.2
1.5
2.0
2.5
3.0
4.0
5.0
6.0
7.0
8.0
10.0
12.0
IFC
51
3.7
4.1
4.6
5.3
6.0
6.5
7.6
8.5
9.3
10.0
10.8
12.1
13.2
IFC
53
6.8
7.1
7.7
8.3
8.8
9.4
10.3
11.0
11.6
12.4
12.6
13.5
14.4
IFC
77
5.8
6.4
7.2
8.4
9.4
10.4
12.1
13.6
15.1
16.4
17.6
19.8
21.8
.
HIGH
-
SEISMIC
INSTANTANEOUS
UNIT
The
instantaneous
coil
is
tapped
for
operation
on
either
one
of
two
ranges
(
H
or
L
)
.
Selection
of
the
high
or
low
range
is
determined
by
the
position
of
the
link
located
on
the
top
of
the
support
structure
(
see
Figure
2
and
Table
V I
)
.
-
7
-
Courtesy of NationalSwitchgear.com
6
EK
-
45375
TABLE
VI
One
High
-
Seismic
Instantaneous
Link
Range
Unit
(
Amps
)
Position
(
Amps
)
Continuous
Second
Rating Rating
(
Amps
)
(
Amps
)
K
2
-
10
2.7
10
-
50
7.5
L
2
-
5 0
130
16
,
900
H
6
-
3 0
10.2
30
-
150
19.6
L
6
-
150
260
67
,
600
H
The
range
is
approximate
,
which
means
that
the
2
-
10
,
10
-
50
may
be
2
-
8
,
8
-
50
.
There
will
always
be
at
least
one
ampere
overlap
between
the
maximum
L
setting
and
the
minimum
H
setting
.
Whenever
possible
,
be
sure
to
select
the
higher
range
,
since
it
has
the
higher
continuous
rating
.
Higher
currents
may
be
applied
for
shorter
lengths
of
time
in
accordance
with
the
formula
:
I
=
VK
/
T
Since
the
instantaneous
unit
coil
is
in
series
with
the
time
overcurrent
unit
coil
,
see
Tables
III
,
IV
,
V
and
VI
to
determine
the
current
-
limiting
element
for
both
continuous
and
short
-
time
ratings
.
HIGH
-
SEISMIC
TARGET
AND
SEAL
-
IN
UNIT
Ratings
for
the
target
and
seal
-
in
unit
are
shown
in
Table
VII
.
TABLE
VII
Tap
0.2
2
DC
Resistance
±
10
%
(
ohms
)
Min
.
Operating
(
Amps
)
+
0
-
60
%
Carry
Continuous
(
Amperes
)
Carry
30
Amps
for
(
sec
.
)
Carry
10
Amps
for
(
sec
.
)
60
Hz
Impedance
(
ohms
)
8.0
0.24
0.2
2.0
0.3
3
0.03
4
0.25
30
68.6
0.73
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
.
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
.
-
8
-
Courtesy of NationalSwitchgear.com
GEK
-
45375
BURDENS
Burdens
for
the
time
overcurrent
unit
are
given
in
Table
VIII
.
TABLE
VIII
Min
Burdens
at
Min
.
Pickup
Min
.
Tap
(
Ohms
)
Burdens
in
Ohms
(
Z
)
Times
Pickup
Tap
Model
Hz
Range
Amps
10
20
Jx
3
R
Z
0.5
-
4.0
0.5
5.43
21.53
22.20
12.55
5.14
3.29
1.0
-
12.0
1.0
1.475
.
3 4
5.54
3.09
1.28
0.82
IFC
51
60
4.47
3.10
1.93
1.11
0.78
0.49
0.5
-
4.0
0.5
1.52
4.23
4.50
1.0
-
12.0
1.0
0.38
1.06
1.13
IFC
53
60
0.5
-
4.0
0.5
1.55
2.36
2.82
1.0
-
12.0
1.0
0.59
0.43
0.73
2.86
2.93
2.76
0.74
0.75
0.70
IFC
77
60
0.5
-
4.0
0.5
4.53
17.95
18.50
11.45
4.28
2.70
1.0
-
12.0
1.0
1.22
4.45
4.62
2.58
1.07
0.68
IFC
51
50
3.72
2.58
1.61
0.93
0.65
0.41
0.5
-
4.0
0.5
1.27
3.52
3.75
1.0
-
12.0
1.0
0.32
0.88
0.94
IFC
53
50
0.5
-
4.0
0.5
1.29
1.97
2.35
1.0
-
12.0
1.0
0.49
0.36
0.61
2.38
2.44
2.30
0.62
0.63
0.58
IFC
77
50
Note
:
The
impedance
values
given
are
those
for
minimum
tap
of
each
range
;
the
impedance
for
other
taps
at
pickup
current
(
tap
rating
)
varies
inversely
(
approximately
)
as
the
square
of
the
tap
rating
.
For
example
,
an
IFC
77
60
Hz
relay
with
0.5
-
4.0
amp
range
has
an
Impedance
of
2.82
ohms
on
the
0.5
amp
tap
.
The
impedance
of
the
2.0
amp
tap
is
(
0.5
/
2.0
)
2
x
2.82
=
0.176
ohms
.
The
High
-
Seismic
instantaneous
unit
burdens
are
listed
in
Table
IX
.
TABLE
IX
Burdens
at
Min
.
Pickup
Min
.
Tap
(
Ohms
)
Burdens
in
Ohms
(
Z
)
Times
Pickup
High
-
Seismic
Inst
.
Hz
Unit
(
Amps
)
Min
.
Pick
-
Link
Range
up
Posi
-
(
Amps
)
Amps
tion
10
3
20
Z
R
Jx
0.750
0.650
0.982
0.070
0.024
0.079
0.634
0.480
0.457
0.072
0.071
0.070
2
-
10
2
10
-
50
10
60
L
H
2
-
50
0.095
0.081
0.079
0.022
0.022
0.022
0.110
0.078
0.135
0.022
0.005 0.023
6
-
150
60
L
6
6
-
30
30
-
150
30
H
0.528
0.400 0.380
0.060
0.059
0.058
0.625
0.542
0.827
0.058
0.020
0.062
2
-
10
2
50
L
H
2
-
50
10
-
50
10
0.092
0.065
0.112
0.018
0.004
0.019
0.079
0.068
0.066
0.018 0.018
0.018
6
-
150
50
L
6
-
30
6
30
-
150
30
H
9
Courtesy of NationalSwitchgear.com
GEK
-
45375
CHARACTERISTICS
TIME
OVERCURRENT
UNIT
Pickup
Pickup
in
these
relays
is
defined
as
the
current
required
to
close
the
contacts
from
the
0.5
time
dial
position
.
Current
settings
are
made
by
means
of
two
movable
leads
which
connect
to
the
tap
block
at
the
top
of
the
support
structure
(
see
Figure
1
)
.
The
tap
block
is
marked
A
through
J
,
A
through
M
or
A
through
N
.
See
the
nameplate
on
the
relay
for
tap
settings
.
Example
:
The
2
amp
tap
for
a
1
to
12
IFC
77
time
overcurrent
relay
requires
one
movable
lead
in
position
D
and
the
other
in
position
H
.
Operating
Time
Accuracy
The
IFC
relays
should
operate
within
1
1
%
or
±
the
time
dial
setting
times
0.10
second
,
whichever
is
greater
,
of
the
published
time
curve
.
Figures
6
-
8
and
20
-
22
show
the
various
time
-
current
characteristics
for
the
IFC
relays
.
The
setting
of
the
time
dial
determines
the
length
of
time
required
to
close
the
contacts
for
a
given
current
.
The
higher
the
time
dial
setting
,
the
longer
the
operating
time
.
The
contacts
are
just
closed
when
the
time
dial
is
set
to
0
.
The
maximum
time
setting
occurs
when
the
time
dial
is
set
to
10
and
the
disk
has
to
travel
its
maximum
distance
to
close
the
contacts
.
Reset
The
unit
resets
at
90
%
of
the
minimum
closing
current
.
Reset
times
are
proportionate
to
the
time
dial
settings
.
The
time
to
reset
to
the
number
10
time
dial
position
when
the
current
is
reduced
to
0
is
approximately
60
seconds
for
the
IFC
53
and
77
relays
.
The
IFC
51
relay
will
reset
in
approximately
12
seconds
from
the
same
number
10
time
dial
.
HIGH
-
SEISMIC
INSTANTANEOUS
UNIT
The
instantaneous
unit
has
a
25
to
1
range
with
a
tapped
coil
.
There
are
high
and
low
ranges
,
selected
by
means
of
a
link
located
on
the
top
of
the
support
structure
.
is
shown
in
Figure
14
.
See
Figure
1
.
The
time
-
current
curve
for
the
instantaneous
unit
HIGH
-
SEISMIC
TARGET
AND
SEAL
-
IN
UNIT
The
target
and
seal
-
in
unit
has
two
tap
selections
located
on
the
front
of
the
unit
.
See
Figure
1
.
RECEIVING
,
HANDLING
AND
STORAGE
These
relays
,
when
not
included
as
part
of
a
control
panel
,
will
be
shipped
in
cartons
designed
to
protect
them
against
damage
.
Immediately
upon
receipt
of
-
10
-
Courtesy of NationalSwitchgear.com
GEK
-
45375
a
relay
,
examine
it
for
any
damage
sustained
in
transit
,
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
.
If
injury
or
damage
Reasonable
care
should
be
exercised
in
unpacking
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
.
ACCEPTANCE
TESTS
Immediately
upon
receipt
of
the
relay
,
an
inspection
and
acceptance
test
should
be
made
to
insure
that
no
damage
has
been
sustained
in
shipment
and
that
the
relay
calibrations
have
not
been
disturbed
,
test
indicates
that
readjustment
is
necessary
,
refer
to
the
section
on
SERVICING
.
If
the
examination
or
These
tests
may
be
performed
as
part
of
the
installation
or
of
the
acceptance
tests
,
at
the
discretion
of
the
user
.
Since
most
operating
companies
use
different
procedures
for
acceptance
and
installation
tests
,
the
following
section
includes
all
applicable
tests
that
may
be
performed
on
these
relays
.
VISUAL
INSPECTION
Check
the
nameplate
stamping
to
insure
that
the
model
number
,
rating
and
calibration
range
of
the
relay
received
agree
with
the
requisition
.
Remove
the
relay
from
its
case
and
check
by
visual
inspection
that
there
are
no
broken
or
cracked
molded
parts
or
other
signs
of
physical
damage
.
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
each
other
.
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
/
64
"
wipe
on
the
seal
-
in
and
the
instantaneous
contacts
.
2
.
3
.
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
button
is
operated
.
4
.
-
11
-
Courtesy of NationalSwitchgear.com
GEK
-
45375
5
.
Make
sure
that
the
brushes
and
shorting
bars
agree
with
the
internal
connections
diagram
.
Check
that
all
screws
are
tight
.
6
.
CAUTION
SHOULD
THERE
BE
A
NEED
TO
TIGHTEN
ANY
SCREWS
,
DO
NOT
OVERTIGHTEN
,
TO
PREVENT
STRIPPING
.
DRAWOUT
RELAY
TESTING
The
IFC
relays
may
be
tested
without
removing
them
from
the
panel
by
using
the
12
XCA
11
A
1
four
-
point
test
probes
.
The
I
2
XCA
11
A
2
four
-
point
test
probe
makes
connections
to
both
the
relay
and
the
external
circuitry
,
which
provides
maximum
flexibility
but
requires
reasonable
care
,
since
a
CT
shorting
jumper
is
necessary
when
testing
the
relay
.
The
CT
circuit
may
also
be
tested
by
using
an
ammeter
instead
of
the
shorting
jumper
.
See
the
test
circuit
in
Figure
15
.
GENERAL
POWER
REQUIREMENTS
All
alternating
current
(
AC
)
operated
devices
are
affected
by
frequency
.
Since
non
-
sinusoidal
waveforms
can
be
analyzed
as
a
fundamental
frequency
plus
harmonics
of
the
fundamental
frequency
,
it
follows
that
AC
devices
(
relays
)
will
be
affected
by
the
applied
waveform
.
Therefore
,
in
order
to
properly
test
AC
relays
it
is
essential
to
use
a
sine
wave
of
current
and
/
or
voltage
.
The
purity
of
the
sine
wave
(
i
.
e
.
,
its
freedom
from
harmonics
)
cannot
be
expressed
as
a
finite
number
for
any
particular
relay
;
however
,
any
relay
using
tuned
circuits
,
R
-
L
or
RC
networks
,
or
saturating
electromagnets
(
such
as
time
overcurrent
relays
)
would
be
essentially
affected
by
non
-
sinusoidal
waveforms
.
Hence
a
resistance
-
1
imi
ted
circuit
,
as
shown
in
Figures
16
-
18
,
is
recommended
.
TIKE
OVERCURRENT
UNIT
Rotate
the
time
dial
slowly
and
check
by
means
of
a
lamp
that
the
contacts
just
close
at
the
0
time
dial
setting
.
The
point
at
which
the
contacts
just
close
can
be
adjusted
by
running
the
stationary
contact
brush
in
or
out
by
means
of
its
adjusting
screw
.
With
the
contacts
just
closing
at
No
.
0
time
setting
,
there
should
be
sufficient
gap
between
the
stationary
contact
brush
and
its
metal
backing
strip
to
ensure
approximately
1
/
32
"
wipe
.
The
minimum
current
at
which
the
contacts
will
just
close
is
determined
by
the
tap
setting
in
the
tap
block
at
the
top
of
the
support
structure
.
CHARACTERISTICS
section
.
See
The
pickup
of
the
time
overcurrent
unit
for
any
current
tap
setting
is
adjusted
by
means
of
a
spring
-
adjusting
ring
.
See
Figure
1
.
The
spring
-
-
12
-
Courtesy of NationalSwitchgear.com
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