GE AKR-75 Series Instructions - Installation And Operation page 5

GEr-861518
DRAWOUT BREAKERS
GENERAL
Drawout breakers
are manufactured
in four
different
styles, identified
in
Table
2 by the
mounting code letters
None, A,
B
&
C.
The "no-letter"
models are
used
in General
Electric's AKD Switchgear. Code A breakers
were later intro-
duced with AKD-5 Switchgear
and
feature closed-door draw-
out ooeration. Code B
breakers
provide an alternate closed-
door drawout arrangement with
the
stationary
element
furnished
as
a preassembled "substructure". Code
C
breakers are exclusively for
AKD-6
Switchgear; they employ
the Code A
drawout mechanism
but
have finger-type
primary
studs instead of tubular. The construction and operation
of
each
of these
drawout
styles is covered under respective
headings in the following text.
As
a general rule,
breakers
of the same
drawout
type,
voltage rating and ampere frame size are
physically
inter-
changeable. In addition,
to be
electrically interchangeable
with
respect
to
secondary
and control
circults,
they
must
have
duplicate wiring. The degree of interchangeability and
the
mechanisms
for
controlling
it
are discussed separately
on page
1
7.
NOTE:
The
four
drawout types
are
mutually non-
interchangeable;
before attempting
to
insert
a
breaker, verify
that
the
breaker model matches
the
compartment.
No
CODE LETTER
(AKD SWITCHGEAR)
(Fig.
1)
These
"no-lette/'
AKR-75/'l 00 models are
replacements
for their AK-75
and
AK-100 predecessors
in
AKD switchgear.
The racking mechanism
is
breaker-mounted
and
the
breakers are bolted to a roller-mounted tray in an arrange-
ment similar to the
B
Type (see page 8).
In addition to
the
characteristics listed in Table 1,
the
AKD drawout has
the
following unique
aspects:
1.
There
are
three (3)
distinct drawout
positions
-
CON-
NECTED, TEST and
WITHDRAWN.
2.
Racking travel occurs only
between
the
CONNECTED
position and
a
point just
short of reaching the TEST position.
3.
The compartment door must
be
open during
racking.
Breaker Insertion (AKD
Type)
1.
Prior
to lifting a breaker to
its intended compartment
location, observe the following
precautions:
a.
Check
the
compartment
to
insure that
it is
free
of
foreign
objects.
b.
Verify
that the breaker
is
the correct type for
that
compartment.
c.
Insure that the breaker ls
OPEN.
d.
Apply athin,
fresh coat of D50HD38
lubricantto
the
b re
ake r's p ri m
ary
di
sco
n
n
ects.
e.
lnsure that
the racking
cams
on the breaker
are
correctly positioned for initial engagement with
the
pins in the
compartment.
To
do this,
insert the rack-
ing
handle and rotate it
fully clockwise.
t.
lf
a
compartment
contains a keylock,
it
will not
ac'
cept the
AKR-751100
replacement breakers
as re-
ceived. The
AKR
drawout mechanism
differs
from
that of
its
predecessor AK model, causing the
AKR
breaker
to mechanically
interfere with the keylock
during breaker insertion.
To
remedy this
it
will
be
necessary
to
relocate the
keylock
using new
mount-
ing hardware
included as a modification
kit.
So
al-
tered, the compartment
accepts both AK
and
AKR
types.
2.
Using
a suitable lifting mechanism and spreader
rig,
position lifting hooks
at
the cutout notches in
the top wrap-
around
f
rames
of
the breaker. Exercise care
to
avoid damage
to the control
wiring.
3.
Open the compartment.door. Keeping the rollout
tray
positioned
inside
the compartment, raise the breaker above
the elevation of the tray.
4.
Depress
the
test position stop lever and
pull the tray
all
the way
out
to
its WITHDRAWN
position.
5.
Lower
the breaker over the tray until it is about one-
half
inch above
the two dowel pins on the tray.
Push the
breaker back into
the
comoartment
until
the rear
bottom
flange
of the breaker rests against the guides behind
the
dowel
oins.
6.
Slowly lower and guide the breaker onto the tray
so
the
holes in
the
rear flange fit
over the two dowel pins. When
correctly positioned
on the
dowel pins, the breaker's rear and
side bottom flanges
will
rest firmly on the tray.
7.
Secure the breakerto
the
tray
by
inserting
and
tighten-
ing
two-s/e
inch hex-head screws
into the
front
holes of its
side
flanges.
8.
lf
the breaker
is a
manually operated
type,
push
it into
the
compartment
until
the
TEST position stop
engages,
preventing further travel.
The breaker
is
now in the
TEST
position.
lf
the
breaker
is
electrically operated,
push
it
into
the
compartment until
the
spring discharge stop is
encountered.
Release this
by
depressing
the
"spring discharge"
lever on
the
bottom of the breaker (see fig.
1),
then
continue pushing the
breaker into the
compartment until
the TEST position
stop
engages.
NOTE:A sprlng discharge stopwill
not
be presentin
some AKD-type compartments originally furnished
for electrically operated
AK-75 and AK-100 breakers
of the
non-quick-close
type.
9.
Depress
the
TEST position stop lever and push
the
breakerfarther intothe compartment
until the
outersurfaces of
the racking cams butt against the racking pins
in
the housing.
10.
Insert
the
racking handle (673D0500-636-05)
on the
jackscrew
shaft at the upper right side
of
the
breaker. Rotate
it clockwise until the jackscrew comes
to
a solid stop. The
breaker is now in the CONNECTED
oosition.
5