GE AK-50 - Long Time-Delay and High-Set Instantaneous Tripping (EC-2); Low-Set Instantaneous Tripping (EC-2); High-Set Instantaneous Tripping (EC-2)

GEI
-
74600
Low
-
voltage
Power
Circuit
Breakers
SERIES
OVERCURRENT
TRIPPING
DEVICE
EC
-
2
(
AK
-
1
-
50
ONLY
)
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
)
.
Jo
)
The
Type
EC
-
2
(
see
Fig
.
26
)
over
-
current
tripping
device
is
available
in
three
forms
:
:
/
At
the
factory
,
the
pick
-
up
point
has
been
set
at
the
nameplate
value
of
the
instantaneous
trip
current
.
(
Usu
-
ally
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
instan
-
taneous
spring
(
5
)
.
Turning
the
ad
-
justment
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
corresponding
change
in
the
spring
load
.
As
the
spring
is
tightened
,
the
pick
-
up
point
is
increased
.
[
MAX
MJN
1
.
Dual
overcurrent
trip
,
with
long
-
time
delay
and
high
-
set
instantaneous
tripping
.
3
3
[
i
v
2
.
Low
-
set
instantaneous
tripping
.
3
.
High
-
set
instantaneous
tripping
.
Fig
.
2
Z
.
Time
-
od
/
usfmenf
indexing
istic
devices
are
shipped
with
this
set
-
ting
at
the
2
/
3
mark
and
the
1
C
char
-
acteristic
at
the
1
/
3
mark
.
The
stand
-
ard
characteristic
curves
are
plotted
at
these
same
settings
.
The
dual
trip
has
adjustable
long
-
time
and
instantaneous
pick
-
up
settings
and
adjustable
time
settings
.
Both
forms
of
instantaneous
trips
have
ad
-
justable
pick
-
up
settings
.
Time
values
are
inversely
propor
-
tional
to
the
effective
length
of
the
dash
-
pot
arm
.
Therefore
,
the
linkage
setting
that
gives
the
shortest
time
value
is
the
one
at
which
dimension
"
A
"
,
Fig
.
26
,
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
neces
-
sary
to
remove
the
case
.
This
may
be
done
by
removing
the
two
mounting
screws
,
one
on
each
side
of
the
case
,
which
may
betaken
off
without
disturb
-
ing
the
trip
unit
itself
.
LONG
TIME
-
DELAY
AND
HIGH
-
SET
INSTANTANEOUS
TRIPPING
(
Fig
.
26
)
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
cali
-
bration
plate
(
2
)
on
the
front
of
the
case
'
^
—
Jrovide
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
.
The
top
edge
of
the
movable
nut
(
11
)
serves
as
an
index
pointer
and
should
be
lined
up
with
the
center
of
the
de
-
sired
calibration
mark
(
15
)
to
obtain
the
proper
instantaneous
trip
setting
.
The
trip
screw
(
6
)
on
the
end
of
the
armature
(
7
)
should
be
set
so
that
it
does
not
contact
the
trip
paddle
on
the
trip
shaft
until
the
air
gap
between
armature
and
pole
piece
is
reduced
to
3
/
32
in
.
or
less
,
measured
at
the
rivet
in
the
pole
piece
.
Also
,
the
armature
must
have
a
minimum
of
1
/
32
in
.
of
travel
beyond
the
point
in
its
motion
at
which
the
breaker
is
tripped
.
As
in
the
case
of
the
EC
-
1
over
-
current
trip
,
the
long
-
time
delay
trip
-
ping
feature
can
be
supplied
with
any
one
of
three
time
-
current
character
-
istics
which
correspond
to
the
NEMA
standards
maximum
,
intermediate
and
minimum
long
-
time
delay
operating
bands
.
These
are
identified
as
1
A
,
IB
and
1
C
characteristics
,
respectively
.
Approximate
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
.
29
.
)
If
the
breaker
is
provided
with
a
shunt
trip
or
undervoltage
device
,
the
EC
-
2
case
on
the
center
pole
must
be
taken
off
first
before
the
cases
on
the
outer
poles
can
be
removed
.
REPLACEMENT
Replacement
of
the
EC
-
2
device
is
accomplished
by
the
same
procedure
described
for
the
EC
-
1
series
trip
de
-
vice
:
however
,
in
some
cases
,
when
replacing
an
EC
-
1
device
with
an
EC
-
2
,
it
will
be
necessary
to
replace
the
trip
paddles
on
the
trip
shaft
with
ones
which
are
slightly
longer
.
When
required
these
will
be
provided
with
the
replac
e
-
ment
trip
units
.
INSTANTANEOUS
LOW
-
SET
TRIPPING
(
Flo
.
26
)
The
low
-
set
instantaneous
pick
-
up
point
may
be
varied
by
the
adjustment
knob
(
3
)
.
The
calibration
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
.
NOTE
:
Pickup
settings
on
the
cover
of
the
EC
-
2
device
are
calibrated
for
the
specific
de
-
vice
.
When
replacing
covers
,
replace
on
associated
device
.
The
tripping
time
may
be
varied
within
the
limits
shown
on
the
charac
-
teristic
curves
by
turning
the
time
ad
-
justment
screw
(
4
)
.
Turning
in
a
clockwise
direction
increases
the
trip
-
ping
time
;
counterclockwise
motion
decreases
it
.
The
dashpot
arm
(
8
)
is
indexed
at
four
points
,
MIN
-
1
/
3
-
2
/
3
-
MAX
,
as
indicated
in
Fig
.
27
.
When
4
he
index
mark
on
the
connecting
link
\
^
J
3
)
lines
up
with
a
mark
on
the
dashpot
Jrm
,
the
approximate
tripping
time
as
INSTANTANEOUS
HIGH
-
SET
TRIPPING
(
Fig
.
26
)
REVERSE
CURRENT
TRIPPING
DEVICE
AK
-
50
ONLY
(
Fig
.
28
)
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
times
coil
rating
.
The
pick
-
up
setting
The
device
is
enclosed
in
a
molded
case
and
is
mounted
on
the
right
pole
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