GE AK-50 Series - EC-1 Adjustments; EC-1 Replacement

Low
Voltage
Power
Circuit
Breakers
GEK
-
7303
force
of
a
non
-
adjustable
spring
.
ADJUSTMENTS
(
Fig
.
27
)
Calibration
claiqping
nuts
(
14
)
are
used
to
set
the
desired
pickup
lor
the
adjustable
elements
.
To
adjust
for
approximately
1
/
32
in
.
over
-
travel
of
trip
arm
(
19
)
after
tripping
:
1
.
Check
trip
latch
engagement
.
See
AD
-
JUSTMENTS
-
OPERATING
MECHANISM
.
2
.
Loosen
the
locknut
*
and
turn
the
adjusting
screw
(
9
)
on
the
trip
arm
(
19
)
.
The
screw
should
not
touch
the
trip
paddle
when
the
breaker
is
"
open
"
.
Adjust
positive
trip
same
as
EC
-
2
A
(
See
page
33
)
.
3
.
Tighten
the
adjusting
screw
locknut
*
on
the
trip
arm
.
2
.
Mount
the
device
as
described
under
re
-
placement
and
insert
the
pin
which
couples
the
connecting
rod
and
the
trip
paddle
.
3
.
Close
the
breaker
and
insert
a
feeler
gage
1
/
32
in
.
thick
between
the
armature
and
magnet
.
This
should
be
done
from
the
rear
of
the
breaker
.
The
feeler
gage
should
be
no
wider
than
1
/
2
in
.
and
at
least
4
inches
long
.
4
.
Close
the
armature
against
the
gage
and
magnet
.
5
.
If
the
breaker
does
not
trip
,
form
paddle
14
to
obtain
positive
trip
.
6
.
Check
visually
to
make
sure
that
the
connecting
rod
does
not
restrict
the
engagement
of
the
breaker
trip
latch
when
the
breaker
mech
-
anism
resets
.
It
should
always
be
possible
to
adjust
its
length
to
a
DOint
where
resetting
is
not
interferred
with
and
yet
positive
tripping
by
the
overcurrent
device
is
achieved
.
SERIES
OVERCURRENT
TRIPPING
DEVICE
EC
-
1
(
Fig
.
27
)
Each
series
overcurrent
tripping
device
is
enclosed
in
a
molded
case
and
mounted
by
three
screws
and
a
bracket
to
the
lower
part
of
the
pole
unit
base
.
*
NOTE
:
In
lieu
of
locknuts
,
some
devices
are
equipped
with
self
-
locking
nylon
insert
nuts
.
REPLACEMENT
(
Fig
.
27
)
1
.
Remove
front
frame
(
see
SEPARATION
OF
FRONT
AND
REAR
FRAMES
)
.
2
.
Remove
the
bolts
holding
the
coil
to
the
lower
stud
.
The
device
can
be
provided
with
the
same
tripping
combinations
as
the
EC
-
1
direct
acting
device
.
SHORT
TIME
-
DELAY
TRIPPING
(
Fig
.
27
)
3
.
Remove
bracket
and
mounting
screws
.
4
.
Before
installing
a
new
device
,
check
the
travel
of
the
trip
arm
with
a
rod
or
wire
and
The
armature
(
7
)
is
restrained
by
cali
-
brating
spring
(
8
)
.
After
the
magnetic
force
produced
by
an
overcurrent
condition
overcomes
this
restraining
force
,
the
armature
movement
is
further
retarded
by
an
escapement
mechan
-
ism
which
produces
an
inverse
time
delay
char
-
acteristic
.
The
mechanism
is
shown
on
Fig
.
27
.
LONG
TIME
-
DELAY
TRIPPING
(
Fig
.
27
)
The
armature
(
10
)
is
restrained
by
the
calib
-
ration
spring
(
11
)
.
After
the
magnetic
force
produced
by
an
overcurrent
condition
overcomes
this
restraining
force
,
the
armature
movement
is
further
retarded
by
the
flow
of
silicone
oil
in
a
dashpot
,
which
produces
an
inverse
time
delay
characteristic
.
The
mechanism
is
shown
on
Fig
.
27
.
INSTANTANEOUS
TRIPPING
(
Fig
.
27
)
(
a
)
Adjustable
instantaneous
tripping
takes
place
after
the
magnetic
force
produced
by
an
over
-
current
condition
,
overcomes
the
restraining
force
of
the
calibration
spring
which
can
be
adjusted
by
the
calibration
clamp
nut
(
14
)
.
(
b
)
Non
-
adjustable
instantaneous
tripping
takes
place
after
the
magnetic
force
produced
by
an
overcurrent
condition
overcomes
the
restraining
Fig
.
28
(
8016188
)
Checking
travel
distance
of
series
overcurrent
tripping
device
29
Courtesy of NationalSwitchgear.com