GE AK-50 Series - Series Overcurrent Tripping Device EC-2;EC-2 A; EC-2;EC-2 A Long-Time;High-Set Tripping; EC-2;EC-2 A Instantaneous Low-Set Tripping; EC-2;EC-2 A Instantaneous High-Set Tripping

Low
Voltage
Power
Circuit
Breakers
GEK
-
7303
SERIES
OVERCURRENT
TRIPPING
DEVICE
EC
-
2
,
EC
-
2
A
,
AK
-
50
case
,
which
may
be
taken
off
without
disturbing
the
trip
unit
itself
.
The
Type
EC
-
2
,
EC
-
2
A
,
(
see
Fig
.
29
)
over
-
current
tripping
device
is
available
in
three
forms
:
1
.
Dual
overcurrent
trip
,
with
long
-
time
delay
and
high
-
set
instantaneous
tripping
.
2
.
Low
-
set
instantaneous
tripping
.
3
.
High
-
set
instantaneous
tripping
.
The
dual
trip
has
adjustable
long
-
time
and
instantaneous
pick
-
up
settings
and
adjustable
time
settings
.
Both
forms
of
instantaneous
trip
have
3
adjustable
pick
-
up
settings
.
LONG
TIME
-
DELAY
AND
HIGH
-
SET
INSTANTANEOUS
TRIPPING
(
Fig
.
29
)
By
means
of
the
adjustment
knob
(
3
)
,
which
can
be
manipulated
by
hand
,
the
current
pick
-
up
point
can
be
varied
from
80
to
160
percent
of
the
series
coil
rating
.
The
indicator
and
a
calibration
plate
(
2
)
on
the
front
of
the
case
provide
a
means
of
indicating
the
pick
-
up
point
setting
in
terms
of
percentage
of
coil
rating
.
The
calibration
plate
is
indexed
at
percentage
settings
of
80
,
100
,
120
,
140
,
and
160
.
If
the
breaker
is
provided
with
a
shunt
trip
or
undervoltage
device
,
the
EC
-
2
,
EC
-
2
A
,
case
on
the
center
pole
must
be
taken
off
first
before
the
cases
on
the
outer
poles
can
be
removed
.
INSTANTANEOUS
LOW
-
SET
TRIPPING
(
Fig
.
29
)
The
low
-
set
instantaneous
pick
-
up
point
may
be
varied
by
the
adjustment
knob
(
3
)
.
The
calib
-
ration
in
this
case
usually
ranges
from
80
percent
to
250
percent
of
the
series
coil
rating
,
with
the
calibration
plate
indexed
at
values
of
80
,
100
,
150
,
200
,
and
250
percent
of
the
rating
.
INSTANTANEOUS
HIGH
-
SET
TRIPPING
Fig
.
29
)
The
high
-
set
instantaneous
pick
-
up
value
may
have
one
of
the
following
three
ranges
:
4
to
9
times
coil
rating
;
6
to
12
times
coil
rating
or
9
to
15
time
coil
rating
.
The
pick
-
up
setting
may
be
varied
by
turning
the
instantaneous
pick
-
up
adjusting
screw
(
12
)
.
Three
calibration
marks
(
15
)
will
appear
on
the
operating
arm
(
14
)
and
the
value
of
these
calibration
marks
will
be
indicated
by
stampings
on
the
arm
as
follows
:
(
4
X
-
6.5
X
-
9
X
)
or
(
6
X
-
9
X
-
12
X
)
or
(
9
X
-
12
X
-
15
X
)
.
At
the
factory
,
the
pick
-
up
point
has
been
set
at
the
nameplate
value
of
the
instantaneous
trip
current
.
(
Usually
expressed
in
times
the
ampere
rating
of
the
trip
coil
.
)
The
variation
in
pick
-
up
setting
is
accomplished
by
varying
the
tensile
force
on
the
instantaneous
spring
(
5
)
.
Turning
the
adjustment
screw
changes
the
position
of
the
movable
nut
(
11
)
on
the
screw
.
The
spring
is
anchored
to
this
movable
nut
so
that
when
the
position
of
the
nut
is
changed
,
there
is
a
corres
-
ponding
change
in
the
spring
load
.
As
the
spring
is
tightened
,
the
pick
-
up
point
is
increased
.
As
in
the
case
of
the
EC
-
1
over
-
current
trip
,
the
long
-
time
delay
tripping
feature
can
be
supplied
with
any
one
of
three
time
-
current
characteristics
which
correspond
to
the
NEMA
standards
max
-
imum
,
intermediate
and
minimum
long
-
time
delay
operating
bands
.
These
are
identified
as
1
A
,
IB
and
1
C
characteristics
,
respectively
.
Ap
-
proximate
tripping
time
for
each
of
these
,
in
the
same
order
are
30
,
15
,
and
5
seconds
at
600
percent
of
the
pick
-
up
value
of
current
.
(
See
time
-
current
characteristic
curves
,
Fig
.
42
)
.
The
tripping
time
may
be
varied
within
the
limits
shown
on
the
characteristic
curves
by
turn
-
ing
the
time
adjustment
screw
(
4
)
.
Turning
in
a
clockwise
direction
increases
the
tripping
time
;
counterclockwise
motion
decreases
it
.
The
dashpot
arm
(
8
)
is
indexed
at
four
points
,
MIN
-
l
/
3
-
2
/
3
-
MAX
,
as
indicated
in
Fig
.
30
.
mark
on
the
connecting
link
(
9
)
lines
up
with
a
mark
on
the
dashpot
arm
,
the
approximate
tripping
time
as
shown
by
the
characteristic
curve
is
indicated
.
The
1
A
and
IB
characteristic
devices
are
shipped
with
this
setting
at
the
2
/
3
mark
and
the
1
C
characteristic
at
the
1
/
3
mark
.
The
stand
-
ard
characteristic
curves
are
plotted
at
these
same
settings
.
Time
values
are
inversely
proportional
to
the
effective
length
of
the
dashpot
arm
.
Therefore
,
the
linkage
setting
that
gives
the
shortest
time
value
is
the
one
at
which
dimension
"
A
"
,
Fig
.
29
,
is
greatest
.
The
time
adjustment
screw
(
4
)
may
be
turned
by
inserting
a
Phillips
head
screwdriver
through
the
hole
in
the
front
of
the
case
.
If
it
is
desired
to
relate
the
linkage
setting
to
the
index
marks
on
the
linkage
it
will
be
necessary
to
re
-
move
the
case
.
This
may
be
done
by
removing
the
two
mounting
screws
,
one
on
each
side
of
the
When
the
index
N
UaitfiltfllNMMtftfMMliyiillHHHlIilHIUilJiliii
;
|
l
I
'
!
s i
i
{
MAX
3
i
j
!
,
3
1
I
i
,
Fig
.
30
(
417
A
464
)
Time
-
adjustment
indexing
31
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