GE MicroVersaTrip AK-50 User manual

GEI
-
“
MAINTENANCE
MANUAL
GFH
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-
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C
r
V
LOW
-
VOLTAGE POWER
CIRCUIT
BREAKERS
TYPES
t
-
.
AK
-
50
,
AK
-
75
,
AK
-
100
,
AKF
-
1
C
,
AKF
-
1
D
,
AKF
-
2
D
f
LOW VOLTAGE
SWITCHGEAR
DEPARTMENT
GENERAL
0
ELECTRIC
Courtesy of NationalSwitchgear.com

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•
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CONTENTS
Page
3
INTRODUCTION
3
OPERATION
MANUAL
CLOSING
MANUAL
MAINTENANCE
CLOSING
OF
ELECTRICAL
BREAKERS
ELECTRICAL
CLOSING
ELECTRICAL
TRIPPING
3
3
3
4
4
MAINTENANCE
INSERTING
SAFETY
PIN
-
AK
-
50
,
AK
-
75
AND
AK
-
100
INSPECTION
LUBRICATION
'
SEPARATION
OF
FRONT
AND
REAR
FRAMES
.
..
.
TROUBLE
SHOOTING
4
5
5
5
6
7
BASIC
BREAKER
COMPONENTS
ARC
QUENCHERS
POLE
UNIT
ASSEMBLY
.
.
OPERATING
MECHANISMS
AUXILIARY
SWITCH
.
..
.
7
8
11
1 8
1 9
ELECTRICAL
CLOSING
DEVICES
AND
CONTROLS
CLOSING
SWITCH
CUT
-
OFF
SWITCHES
CONTROL
RELAY
19
19
19
4
PROTECTIVE
DEVICES
'
TIME
-
DELAY
UNDERVOLTAGE
TRIPPING
DEVICE
INSTANTANEOUS
UNDERVOLTAGE
TRIPPING
DEVICE
DIRECT
-
ACTING
TRIPPING
DEVICE
-
EC
-
1
DIRECT
-
ACTING
TRIPPING
DEVICES
-
EC
-
1
A
AND
EC
-
IB
SERIES
OVERCURRENT
TRIPPING
DEVICE
-
EC
-
1
SERIES
OVERCURRENT
TRIPPING
DEVICE
-
EC
-
2
(
AK
-
1
-
50
ONLY
)
REVERSE
CURRENT
TRIPPING
DEVICE
(
AK
-
50
ONLY
)
20
20
20
21
22
23
26
26
28
SELECTIVE
TRIPPING
26
BREAKER
ACCESSORIES
PRIMARY
DISCONNECTS
(
AK
-
50
ONLY
)
SECONDARY
DISCONNECTS
DRAWOUT
MECHANISM
SHUNT
-
TRIPPING
DEVICE
BELL
ALARM
AND
LOCKOUT
DEVICE
DYNAMIC
BRAKE
FOR
ELECTRICAL
BREAKERS
28
28
29
29
30
31
32
MISCELLANEOUS
.
.
.
TOOLS
RENEWAL
PARTS
32
32
17
MM
instructions
do
noI
purport
to
cover
a
/
/
dttaf
’
/
c
or
variations
in
equipment
nor
to
provide
for
every
possible
contingency
to
be
met
in
connection
with
mttatiofion
,
operation
or
mointenonce
.
Should
further
information
be
defired
or
should
particular
problems
arise
which
ore
not
covered
sufficiently
for
the
purchaserpurposes
,
the
matter
should
be
referred
to
the
General
Electric
Company
.
Courtesy of NationalSwitchgear.com

LOW
-
VOLTAGE
POWER
CIRCUIT
BREAKERS
Types
AK
-
50
,
AK
-
75
,
AK
-
100
,
AKF
-
1
C
,
AKF
-
1
D
,
AKF
-
2
D
f
1
INTRODUCTION
peciallyfor
use
in
controlling
the shunt
field
circuits
of
synchronous
motors
or
generators
.
These
breakers
are
two
-
pole
power
circuit
breakers with
field
discharge
contacts
placed
in
the
center
pole
.
Opening
of
the breaker
’
s
outer
poles
closes
the field
discharge
contacts
,
thus
connecting
a
discharge
resistor
across
the
field
of
the
genera
-
tor
or
motor
.
Type
AK
power
circuit
breakers
are
are
intended
to
impart
the
necessary
designed
for
general
use
on
all
types
of
information
required
for
proper
main
-
low
-
voltage
circuits
.
These
breakers
tenance
and
replacement
of
component
are
particularly
applicable
for
protec
-
parts
and
accessories
for
AK
-
50
,
-
75
,
tion
and
control
of
feeder
and
branch
-
lOOand
AKF
-
1
C
,
-
ID
,
-
2
Dpowercir
-
circuits
in
buildings
,
industry
,
power
cuit
breakers
.
Before
performing
any
stations
,
and
marine
applications
,
maintenance
procedures
,
the
associ
-
ated
section
(
s
)
of
these instructions
should
be
carefully
and
thoroughly
read
,
cial
type
of
AK
breaker
designed
es
-
The
instructions
contained
herein
r
The
AKF
Type
breakers
are
a
spe
-
OPERATION
NOTE
'
Mil
If
L
;
TSMT
*
*
*
"
•
'
*
*
i
i
MANUAL
CLOSING
REMOVE
JUMPERS
Ah A
3
AND
A
2
-
A 4
WHEN
ALTERNATE
WIRING
IS
USED
For
a
description
of
manual clos
-
ing
,
refer
to
the
section
of
these
in
-
structions
entitled
CLOSING
THE
BREAKER
-
MANUALLY
OPERATED
AK
-
1
-
50
and
the
section
entitled
AK
-
2
-
50
,
-
75
AND
-
100
STORED
ENERGY
MANUAL
MECHANISM
,
both
under
OPERATING
MECHANISMS
.
A
A
!
v
r
-
I f
KB
,
*
* *
f
f
-
T
3
-
KB
—
I
i
i
l
_
.
T
4
—
-
0
2
P
^
-
R
2
—
—
Sfcl
-
Jifcc
:
o
2
]
re
-
KB
—
W
4
K
:
>
r
-
vi
-
HLrJi
—
-
o
r
‘
AOOmONAL
AUK
_
L
CONTACTS
WHEN
REO
.
-
0 4
JL
D
6
L
*
8
!
E
.
SB
-
-
*
-
*
a
—
KS
—
-
o
-
o
2
-
o
Jo
-
0 4
o
o
So
0
(
0
LI
—
5
I
(
I
!
o
4
o
o
S
o
o
6
o
I
2
4
2
*
I
MANUAL
MAINTENANCE
CLOSING
OF ELECTRICAL
BREAKERS
CONNECTION
DIAGRAM
|
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ITT
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FJ
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e
RJ
AJ
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4
2
M
2
)
«
,
T
1
>
An
electrical breaker
may
be
closed
manually by
means
of
the
maintenance
handle furnished
with the breaker
.
M
*
0
I
1
R
-
(
M
TRANS
T
.
C
.
g
“
HV
yi
r
-
O
ND
vn
x
N
To
observe
the
operation
of
the
breaker
without
power
,
with the
breaker
open
and
springs
discharged
,
proceed
as
follows
:
ALTERNATE
WIRING USED
WTTM
FOLLOWING
POWER VOLTAGE
RATING
’
J
00
/
2
JO
VAC
SO
~
460
/
230
VAC
2
S
rv
46
CV
2
J
0
V
AC
50
#
v
46
CV
230
V
AC
60
rv
575
/
2
JO
V
AC
25
rv
575
/
2
JO
V
AC
50
rv
575
/
230
V
.
AC
60
rv
CUSTOMER
WIRING
FACTORY
WIRING
-
FACTORY
WIRING
FOR ENCLOSED BRKRS
CUSTOMER
WIRING
FOR
STATIONARY
BRKRS
.
1
.
Charge
the
closing
spring
with
the
maintenance
handle
(
I
,
Fig
.
3
)
until the indicator reads
Mcbarged
”
.
i
W
MX
-
ter
"
VFUSE
CLOSE
^
FUSE
AI
:
U
AS
2
.
Continue
to
operate
the mainte
-
nance
handle
until the
breaker
closes
.
P B
Bl
TWP
KV
UST
OF
ABBREVIATIONS
2
«
2
LI
KS
A
-
TERMMAL
BOARD
FRONT
VIEW
B
-
TERMINAL
BOARD
LOCATED
LEFT
WOE
FRONT
VIEW
LOCATED
LEFT
ROE
02
«
•
ALDLSW
.
3
.
Open
the
breaker
by
pushing
the
trip
button
(
5
,
Fig
.
2
)
.
J
1
uc
GI
FI
III
64
sT
Kl
>
U
\
fTWP
COIL
)
KJ
OFF SWITCHES
KB
M
2
K
-
CLOSING
RCUW
TYPE
KG
A
.
00
L
-
AUXILIARY
SW
VB
*
b
"
CONTACTS
TYPE
SB
-
12
(
AUX
.
SWJ
M
-
SHUNT
TRIP
(
TGJ
P
-
PUSH
BUTTON
CLOSING
SW
ON
0
RKR
.
I
0
B
)
R
-
CLOSING
SPRING CHARGING
MOTOR
<
M
)
T
-
AUXILIARY
POWER
TRANSFORMER
{
TRANS
)
R
ELECTRICAL
CLOSING
R
2
BJ
A
2
Figure
1
shows
the
typical
ele
-
mentary
and
connection
diagrams
for
the
control
system
of
electrically
oper
-
fitpH
hroalrovc
evranl
hroaborc whirh
ELEACNTARY DIAGRAM
^
L
-
FUSE
-
FUSE
-
<
“
)
Y
l
-
)
Y
Courtesy of NationalSwitchgear.com

GEI
-
74600
Low
-
voltage
Power
Circuit
Breakers
Mechanism
.
It
shows
the
control
cir
-
\
cult
when the
closing
springs
are
dis
-
•
charged
and
the
breaker
open
.
When
rated
voltage
is
applied
to
the
control
circuit
,
the
motor
R
(
l
-
2
)
is
en
-
ergized
through closing
relay
contacts
K
(
8
-
4
)
(
3
-
7
)
and
cutoff
switch
contacts
G
(
2
-
l
)
(
3
-
4
)
.
As
the
motor
charges
the
closing
springs
,
the
F
and
G
cutoff
switches
are
mechanically
operated
,
opening
the
G
contacts
and
closing
the
F
contacts
.
When
contacts
G
(
1
-
2
)
(
3
-
4
)
open
,
the
motor
is de
-
energized
,
with
the
closing
springs
now
in
the
’
tharged
"
position
and
ready
for
a
closing signal
.
The
indicator
on
the
front
escutcheon
will indicate the
charged
position
.
A
closing signal
now
given energizes
the
closing
relay
K
(
5
-
6
)
,
whose
con
-
tacts
K
(
8
-
2
)
(
1
-
7
)
close
,
with the
relay
being
sealed
in
by
contacts
K
(
8
-
2
)
and
F
(
4
-
3
)
.
With
the
closing
relay
ener
-
gized
and the
F
cutoff
switch
contacts
closed
,
the
motor
R
(
l
-
2
)
is
again
ener
-
gized
through
contacts
K
(
8
-
2
)
,
F
(
2
-
l
)
,
and
K
(
l
-
7
)
,
further
charging
the
clos
-
ing springs
and
causing
the
output
crank
of
the
gear
reduction
unit
to
go
over
a
top
dead
-
center
position
.
Be
-
yond
this
position
the
springs
discharge
independently
of
the
charging
motor
sand the
breaker closes
.
6
1
.
Auxiliary
Switch
Z
.
Channel
-
shaped
Bar
3
.
Position
Indicator
4
.
Relay
5
.
Manual
Trip
Button
6
.
Closing
Button
7
.
Shaft
for
Manual
Mainte
-
nance
Closing
Handle
8
.
Spring
Charged
-
Discharged
Indicator
9
.
Motor
Cut
-
off
Switches
10
.
Arc
Quencher
Froni
view
of
AK
-
J
-
50
breaker
Fig
.
2
.
ELECTRICAL
TRIPPING
rotating
the
trip
shaft and
displacing
the
trip
latch
.
When
the breaker closes
,
the
cutoff
switches
revert to
their
original
po
-
sition
and
on
release
of
the
closing
switch
,
relay
x
is
de
-
energized
and
the
motor
recharges
the
springs
to
the
pre
-
charged
position
.
On
some
models
,
an
auxiliary
switch
,
fb
"
contact
is
placed
in
the
motor
circuit
to
prevent
pre
-
charging
when the
breaker is
in
the
closed
position
.
The
breaker
may
be
tripped
elec
-
trically
by
any
of
the
electrical
trip
-
ping
devices described
in
these
in
-
structions
.
The breaker
may
also be
tripped
by
the automatic
over
cur
rent
or
reverse
current
tripping
devices
,
if
so
equipped
.
All
these devices
trip
the
breaker
in
a
similar
manner
,
i
.
e
.
the
device
trip
arm
moves
against
the
trip
paddles
fastened
on
the
trip
shaft
,
thus
The
most
commonly
used
tripping
device
is
the
shunt
trip
device
con
-
nected
in
the control
circuit
as
shown
in
Fig
.
1
.
When
a
tripping signal
is
given
,
the shunt
trip
coil
M
(
i
-
2
)
is
energized through
a
normally
-
open
auxiliary
switch
"
a
"
contact
L
(
l
-
lc
)
,
thus
tripping
the breaker
.
MAINTENANCE
BEFORE
INSPECTION
OR
ANY
MAINTENANCE
WORK IS DONE
,
BE
SURE
THAT
THE
BREAKER
IS
IN
THE
OPEN POSITION
.
ALL
ELEC
-
TRICAL
POWER
,
BOTH
PRIMARY
AND
CONTROL
SOURCES
,
SHOULD
ALSO
BE
DISCONNECTED
.
is
in
the
open
position
and
the
closing
springs
are
being
re
-
strained
by
the
safety
pin
.
The
procedure
for
inserting
the
safety
pin
is
given
below
.
INSERTING SAFETY
PIN
AK
-
50
,
-
75
and
-
100
(
Fi
9
.
3
)
The
closing spring
should
be
charged
with the
maintenance
handle
(
1
)
so
that
the
safety
pin
(
3
)
can
be
placed
in
the hole
of
the
push
rod
(
2
)
.
Con
-
tinue
to
operate
the maintenance
han
-
so
that
the
safety
pin
takes
the
spring
force
*
To
install
the
safety
pin
of
the
AK
-
2
manual stored
-
energy
mecha
-
nism
refer
to
the section
entitled
AK
-
2
STORED
-
ENERGY
MANUAL
MECHA
-
NISM
on
page
14
of
these
instructions
.
Warning
;
On
breakers
em
-
ploying
stored
-
energy
closing
mechanisms
,
care
must
be
taken
when
the
circuit
breaker
is
being
installed
and
when
any
inspection
or
maintenance
work
With
the
safety
pin
restraining
the
closing
spring
force
,
the
contacts
will
close
slowly
when
the
breaker
is
manu
-
ally
operated
allowing
the
operation
of
the mechanism and
the
contact
align
-
i
c
hAi
'
ntr
Arma
enfkaf
tKo
alar
i
nrr
tlto
Kraalrar
c
ie
+
K A
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^
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AKP
nn
Courtesy of NationalSwitchgear.com

Low
-
voltage
Power
Circuit
Brmakors
GEI
-
74600
f
points
and
sliding
surfaces
should
be
lubricated
at
the
regular
inspection
periods
with
a
thin
film
of
G
-
E
Lubri
-
cant
D
50
H
15
.
Hardened
grease
and
dirt
should
be
removed
from
latch
and
bearing
surfaces
by
using
kerosene
.
ALL
EXCESS
LUBRICANT
SHOULD
BE
REMOVED
WITH
A
CLEAN
CLOTH
TO
AVOID
ANY
ACCUMU
-
LATION
OF
DIRT
OR
DUST
.
t
CO
lT
>
0
C
c
at
The
use
of
cotton
waste
to
wipe
bearing
surfaces
should
be
avoided
,
as
the
cotton
ravelings
may
become
entangled
under
the
bearing
surfaces
and
destroy
the
surface
of
the
bearing
.
r
On
drawout
breakers
,
the
contact
surface
of
the
disconnect
studs
should
be
greased
with
G
-
E
Grease
Specifica
-
tion
D
50
H
47
.
SEPARATION
OF
FRONT
AND
REAR
FRAMES
To
repair
or
replace
contacts
,
op
-
erating
mechanism
,
or
the
overcurrent
devices
,
the
front
frame
must
be
sepa
-
rated
from
the
back
frame
.
To
sepa
-
rate
the
two
frames
proceed
as
follows
:
1
.
The
breaker
contacts
must
be
open
with
the
safety
pin
in
place
.
(
See
MAINTENANCE
.
)
2
.
Remove
the
two
opening
springs
(
on
lower
part
of
breaker
)
from
the
outside
pole
units
.
3
.
Remove
the
clevis
pin
(
14
,
Fig
.
6
)
(
13
,
Fig
.
7
)
from
the
center
pole
unit
.
1
.
Manual
Maintenance
Handle
2
.
Push
Rod
3
.
Safety
Pin
View
showing
operation
of
AK
-
I
-
50
breaker
with
manual
maintenance
handle
and
installation
of
safety
pin
Fig
.
3
.
Following
the
inspection
period
,
the
closing
springs
must
be
recharged
,
the
safety
pin
removed
from
the
push
rod
,
and
the
pin
placed
in
the
retain
-
ing
spring
clip
adjacent
to
the
push
rod
.
spection
of
the
breaker
should
be
made
including
connections
,
contacts
and
flexible
connectors
.
(
At
all
times
it
is
important
not
to
permit
pencil
lines
,
paint
,
oil
or
other
foreign
materials
to
remain
on
the
in
-
sulating
surfaces
of
the
breaker
as
they
may
cause
low
resistance
between
points
of
different
potential
and
result
in
eventual
electrical
breakdown
.
INSPECTION
Periodic
inspection
of
the
circuit
breaker
is
recommended
at
least
once
a
year
.
More
frequent
inspections
are
recommended
if
severe
load
conditions
,
dust
,
moisture
or
other
unfavorable
conditions
exist
.
A
complete
inspec
-
tion
of
the
breaker
,
including
contacts
and
arc
quenchers
,
should
always
be
made
after
the
breaker
has
interrupted
a
short
-
circuit
.
4
.
Remove
the
six
nuts
from
the
back
frame
using
a
socket
wrench
with
an
extension
.
These
include
the
two
nuts
at
the
top
of
the
frame
.
5
.
Remove
the
auxiliary
switch
op
-
erating
rod
(
5
,
Fig
.
17
)
.
6
.
Check
along
the
trip
shaft
for
a
mechanical
interference
or
connection
between
the
overcurrent
trip
device
and
the
trip
paddles
.
Remove
mechani
-
cal
connection
if
present
,
or
if
inter
-
ference
exists
,
use
extreme
care
when
removing
or
re
-
assembling
front
and
back
frames
to
avoid
mechanical
break
-
age
of
trip
devices
.
In
reassembling
the
front
and
rear
frames
,
the
two
frames
should
be
positioned
vertically
so
that
the
trip
shaft
is
horizontally
aligned
.
The
breaker
should
be
operated
several
times
at
rated
voltage
to
as
-
sure
that
the
control
circuits
are
properly
connected
and
that
all
elec
-
trical
attachments
are
functioning
properly
.
A
complete
contact
inspection
,
in
-
cluding
contact
wipe
and
pressure
,
should
be
made
at
regular
inspection
periods
and
always
after
a
known
short
circuit
current
has
been
interrupted
,
to
determine
whether
the
contacts
are
worn
or
pitted
in
which
case
they
should
be
dressed
or
replaced
.
It
is
necessary
to
remove
the
arc
quenchers
to
properly
inspect
the
contacts
.
Arcing
contacts
and
arc
quencher
barriers
should
be
replaced
when
they
are
eroded
to
half
their
original
thickness
.
At
regular
inspection
periods
the
breaker
should
be
operated
manually
;
(
stored
energy
mechanisms
with
the
safety
pin
restraining
the
closing
spring
force
)
to
observe
the
contact
alignment
and
to
make
sure
all
mecha
-
nism
parts
move
freely
without
binding
or
excessive
friction
.
If
the
breaker
remains
open
or
closed
for
a
period
of
six
months
or
more
,
it
is
recommended
that
arrange
-
ments
be
made
to
open
and
close
it
several
times
in
succession
,
prefer
-
ably
under
load
.
NOTE
:
It
is
recommended
that
the
breaker
be
fastened
to
a
suitable
mounting
base
with
the
front
frame
supported
by
a
sling
or
hook
as
the
bolts
are
LUBRICATION
If
overheating
,
not
caused
by
over
-
current
.
is
observed
,
a
comnletp
in
-
In
general
,
the
circuit
breaker
re
-
miirAfi
mnHprnt
*
*
lnhriratinn
R
^
arino
-
Courtesy of NationalSwitchgear.com

GE
/
-
74600
Low
-
voltag
*
Powmr
Circuit
Bnakws
TROUBLE
SHOOTING
\
CAUSE
TROUBLE
REMEDY
Contacts
not
aligned
.
Contacts
dirty
,
greasy
or
coated
with
dark
film
.
Contacts
badly
burned
or
pitted
.
Current
-
carrying
surfaces
dirty
.
Overheating
Adjust
contacts
.
Clean
contacts
.
Replace
contacts
.
Clean
surfaces
of
current
-
carrying
parts
.
Relocate
or
provide
adequate
enclo
-
sure
.
Corrosive
atmosphere
.
Insufficient
bus
or
*
cable
capacity
.
Increase
capacity
of
bus
or
cable
.
Bolts
and
nuts
at
terminal
connections
not
tight
.
Tighten
,
but
do
not
exceed
,
elastic
limit
of
bolts
or
fittings
.
Current
in
excess
of
breaker
rating
.
Check
breaker
application
or
modify
circuit
by
decreasing
load
.
Excessive
ambient
temperature
.
Provide
adequate
ventilation
.
Inductive
heating
.
Correct
bus
or
cable
arrangement
.
Travel
of
tripping
device
does
not
provide
positive
release
of
tripping
latch
.
Worn
or
damaged
trip
unit
parts
.
Binds
in
overcurrent
trip
device
.
Failure
to
Trip
Re
-
adjust
or
replace
tripping
device
.
Replace
trip
unit
.
Replace
overcurrent
trip
device
.
Check
application
of
overcurrent
trip
device
.
Check
application
of
overcurrent
trip
device
.
Replace
overcurrent
trip
device
.
Overcurrent
pick
up
too
low
.
False
Tripping
Overcurrent
time
setting
too
short
.
Bind
in
overcurrent
trip
device
.
Failure
to
Close
and
Latch
Re
-
align
and
adjust
attachments
.
Binding
in
attachments
preventing
resetting
of
latch
Latch
out
of
adjustment
.
Latch
return
spring
too
weak
or
broken
.
Adjust
latch
.
Replace
spring
.
Clean
bearing
and
latch
surfaces
.
Hardened
or
gummy
lubricant
.
Safety
pin
left
in
push
rod
.
Motor
burned
out
.
Remove
safety
pin
.
Replace
motor
.
Replace
or
adjust
faulty
device
.
Faulty
control
circuit
component
.
Burned
Main
Contacts
Improper
contact
sequence
(
main
contacts
not
sufficiently
parted
when
arcing
contacts
part
)
.
Increase
arcing
contact
wipe
.
Adjust
contact
sequence
by
raising
or
lowering
main
movable
contact
pivot
block
.
Short
-
circuit
current
level
above
interrupting
rating
of
breaker
.
Requires
system
study
and
possible
replacement
with
breaker
having
adequate
interrupting
capacity
.
Loss
of
contact
wipe
or
pressure
.
Replace
stationary
contact
springs
Courtesy of NationalSwitchgear.com

Low
-
voltage
Power
Circuit
Breakers
GEI
-
74600
f
BASIC
BREAKER
COMPONENTS
1
DISASSEMBLY
—
AK AND AKF
CENTER
POLE
(
Fig
.
4
)
REPLACEMENT
—
AKF
BREAKERS
ARC
QUENCHERS
(
Fig
*
4
and
5
)
The
center
-
pole
arc
quencher
of
these breakers is similar
to
the
arc
The
following
instructions
apply
to
quenchers
of
the
standard
breakers and both the
Type
AK
and
AKF
breaker
is
replaced
in
a
similar
manner
,
except
center
poles
,
that
the breaker
must
be
closed
.
With
The
arc
quenchers
should
be
in
-
spected
at
the
regular
inspection
period
.
If
the barriers
are
cracked
or
eroded
to
one
-
half
their
original
thickness
,
they
should be
replaced
.
1
.
Remove
arc
quenchers
(
see
the breaker
closed
the
center
-
pole
contacts
are
open
and the
arc
quencher
REPLACEMENT
)
,
can
be
removed
.
r
REPLACEMENT
—
AK
BREAKERS
2
.
Remove
screws
holding
spacer
block
(
9
)
.
Replace
the
outer
-
pole
arc
quen
-
chers
of
the
Type
AKF
breaker
as
follows
;
1
.
Be
sure
the breaker is
open
.
3
.
Remove
spacer
block
,
steel
back
plate
(
8
)
,
and
compound
support
(
7
)
.
2
Remove
the channel
-
shaped
re
-
taining
bar
by
removing
two
screws
and
two
nuts
.
4
.
Rock muffler
(
6
)
slightly
and
re
-
move
.
The
inner
barriers
(
5
)
can
now
2
.
Remove
the
two
channel
-
shaped
be removed
for
inspection
,
retaining
bars which bear
against
the
front of
the
arc
quencher
by
removing
four
screws
,
two
on
each
side
.
1
.
Be
sure
the breaker
is
open
.
3
.
Lift
the
quenchers
clear
of
the
movable
arcing
contacts
.
5
.
Remove
nut
and withdraw
stud
(
1
)
.
6
.
Remove
cap
(
2
)
.
The
side
(
3
)
and
pocket
(
4
)
barriers
should
be
free
.
4
.
During
replacement
be
careful
not to
overtighten
the
screws
which
se
-
cure
the channel
-
shaped
retainingbar
.
Overtightening
the
screws
will bow
the
bar and
leave the
center
arc
quen
-
cher
loose
.
3
.
Lift
the
arc
quenchers
clear
of
the movable
arcing
contacts
.
7
.
Reassemble
and
replace
the
arc
quencher
in
the
reverse
order
.
Tighten
the
fastenings
after
replacement
.
4
.
Replace
arc
quenchers
and
in
-
sert
the
four
screws
holding
the
re
-
taining
bars
in
position
.
c
©
CO
©
CO
-
A
*
-
V
*
V
*
>
.
r
v
.
.
it
-
Y
~
.
»
i
.
I
2
3
4
5
6
7
9
8
?
.
Compound
Support
8
.
Steel
Back Plate
9
.
Spacer
Block
4
.
Pocket
Barrier
5
.
Inner
Barrier
6
.
Muffler
1
.
Stud
2
.
Cap
3
.
Side
Barrier
W
Courtesy of NationalSwitchgear.com

G
£
1
-
74600
Low
-
voltage
Power
Circuit
Breakers
1
.
Muffler
A
ssembly
2
.
Spacer
Block
3
.
Inner
Barrier
4
.
Cap
5
.
Intermediate
Barrier
6
.
Outer
Barrier
7
.
Side
Plate
Disoisemb
/
ed
ore
quenene
AKF
oufer
pc
/
c
:
DISASSEMBLY
—
AKF
OUTER
POLES
(
Fig
.
5
)
Table
1
gives
the
figures
for
contact
pressure
and
contact
wipe
.
Both
wipe
and
pressure
should
be
checked
dur
-
ing
the
regular
inspection
period
.
MEASURING
CONTACT
WIPE
(
Fig
.
6
)
1
.
Remove
arc
quenchers
(
see
RE
-
PLACEMENT
under
ARC
QUEN
-
CHER
)
.
2
.
With
the
breaker
open
,
measure
the
horizontal
distance
from
the
edge
of
the
stationary
contact
to
the
sta
-
tionary
block
behind
it
.
(
"
B
"
dim
.
for
arcing
contacts
,
"
CM
dim
.
for
main
contacts
.
)
3
.
Close
the
breaker
and
repeat
item
2
.
The
difference
between
the
readings
in
items
2
and
3
determines
the
wipe
of
the
contacts
.
For
safety
reasons
be
extremely
careful
not
to
trip
the
breaker
.
MEASURING
CONTACT
PRESSURE
(
Fig
.
6
)
1
.
Remove
arc
quenchers
(
see
RE
-
PLACEMENT
under
ARC
QUEN
-
CHER
)
.
2
.
Close
the
breaker
and
measure
dimension
"
B
"
.
3
.
Open
the
breaker
.
Place
a
push
-
type
scale
against
the
stationary
arc
-
ing
contacts
at
a
point
measured
in
line
with
the
break
between
the
con
-
tact
stop
and
the
contact
pivot
block
.
Push
the
contact
backward
until
di
-
mension
MBH
recorded
in
item
2
is
reached
.
The
scale
should
then
be
read
.
4
.
If
the
pressure
is
not
within
the
requirements
listed
on
TABLE
I
,
re
-
fer
to
the
section
of
these
instructions
dealing
with
ADJUSTING
CONTACT
WIPE
AND
PRESSURE
.
travel
of
the
contacts
.
Flexible
braid
leads
(
5
)
shunt
the
pivot
pin
to
prevent
possible
pitting
at
the
pivot
point
when
interrupting
high
currents
.
On
later
model
breakers
shunting
springs
are
used
in
place
of
braids
.
The
movable
arcing
-
contact
assem
-
bly
consists
of
parallel
contact
arms
(
4
)
carried
on
two
movable
pivot
pins
(
8
)
and
(
19
)
.
The
arcing
contacts
in
-
terleave
the
main
contacts
and
pivot
with
them
about
pin
(
19
)
.
This
rela
-
tive
motion
is
obtained
by
linkages
from
the
upper
pin
(
7
)
to
the
breaker
mechanism
.
I
,
Remove
arc
quenchers
(
see
above
)
and
lay
on
sides
on
a
flat
sur
-
face
.
2
.
Remove
hardware
from
one
side
of
arc
quencher
as
indicated
in
Fig
.
5
.
3
.
Remove
bolt
fastening
cap
(
4
)
and
barrier
plate
assembly
.
i
4
.
Barrier
plates
may
now
be
lifted
from
assembly
for
inspection
.
5
.
In
reassembling
,
make
sure
components
are
positioned
so
that
holes
for
self
-
tapping
hardware
are
in
line
.
Do
not
strip
threads
in
compound
by
overstressing
screws
.
The
stationary
main
contact
assem
-
bly
includes
main
and
intermediate
contacts
.
The
inter
mediate
-
contact
surface
extends
beyond
the
main
con
-
tacts
and
will
,
therefore
,
make
before
the
main
contacts
and
break
after
the
main
contacts
.
The
number
of
con
-
tacts
for
each
breaker
rating
is
given
in
Table
I
,
The
movable
main
contacts
pivot
around
a
stationary
pin
(
18
)
,
which
holds
them
to
the
lower
block
.
Motion
is
obtained
from
a
second
pin
(
7
)
,
con
-
nected
by
an
insulated
link
(
12
)
to
the
breaker
mechanism
.
In
addition
to
flexible
braids
shunting
the
current
from
the
contact
directly
to
the
lower
contact
block
,
steel
springs
(
17
)
force
the
contacts
against
the
pins
to
pre
-
vent
pitting
at
the
pivot
point
.
The
movable
main
contact
assembly
also
contains
main
and
intermediate
con
-
tacts
.
POLE
UNIT
ASSEMBLY
(
Fig
*
6
)
NOTE
:
The
text
and
part
iden
-
tification
numbers
contained
in
this
section
apply
to
illustra
-
tions
covering
the
AK
-
50
breaker
.
The
same
text
is
ap
-
plicable
to
the
AK
-
75
and
100
breakers
by
referring
to
Fig
.
7
and
identifying
the
similar
parts
.
These
similar
parts
may
not
,
in
every
case
,
be
iden
-
tified
by
the
same
number
.
Each
pole
unit
assembly
consists
of
a
set
of
arcing
contacts
,
a
set
of
main
contacts
,
the
actuating
linkage
and
the
mounting
base
.
See
Fig
.
8
and
9
,
pole
unit
assemblies
mounted
on
back
frame
assemblies
.
The
stationary
arcing
-
contact
as
-
sembly
consists
of
a
set
of
parallel
contact
fingers
(
2
)
,
pin
(
3
)
,
and
com
-
pression
springs
(
22
)
,
which
provide
continuous
contact
pressure
for
the
full
In
order
to
function
properly
,
a
definite
amount
of
contact
pressure
and
contact
wipe
must
exist
between
the
movable
and
stationary
contacts
.
Courtesy of NationalSwitchgear.com

Low
-
voltage
Power
Circuit
Breakers
GCI
-
74600
TABLE
I
r
-
•
*
Intermediate
Contacts
Main
Contacts
Arcing
Contacts
Pres
-
sure
in
Lbs
.
Wipe
No
.
of
Contacts
Per
Pole
Pres
-
sure
in
Lbs
.
No
.
of
Contacts
Per
Pole
Pres
-
sure
in
Lbs
.
No
.
of
Contacts
Per
Pole
Wipe Wipe
Breaker
Type
in
in
in
Inches
Inches Inches
1
/
16
to
16
/
64
to
23
/
64
55
to
65
AK
-
50
for
AC
3
55
to
65
I
2
31
to
43
*
3
/
32
1
/
16
to
16
/
64
to
23
/
64
AK
-
50
for
DC
55
to
65 3 31
to
43
3
55
to
65
1
3
/
32
r
1
/
16
to
16
/
64
to
23
/
64
AK
-
75
for
AC
35
to
45
1
35
to
45 3 31
to
43
5
*
3
/
32
1
/
16
to
16
/
64
to
23
/
64
AK
-
75
for
DC
5
35
to
45
1
35
to
45
5
31
to
43
*
3
/
32
1
/
16
to
16
/
64
to
23
/
64
AK
-
100
for
AC
AK
-
100
for
DC
25
to
35
2
25
to
35
5
*
8 31
to
43
3
/
32
16
/
64
to
23
/
64
1
/
16
to
55
to
65
1
55
to
65
2
AKF
-
1
C
(
Outside
Poles
)
3
*
31
to
43
3
/
32
AKF
-
lD
(
Outside
AKF
-
2
D
Poles
)
1
/
16
to
16
/
64
to
23
/
64
55
to
65
5
55
to
65
1
*
3
31
to
43
3
/
32
AKF
-
1
C
(
Field
AKF
-
ID
Discharge
Contacts
)
3
/
16
to
7
/
16
*
*
2
* *
10
to
16
0
0
c
*
The intermediate
contact
wipe
should be
at
least
1
/
16
in
.
greater
than main
contact
wipe
.
*
*
Left
stationary
contact
extends
approximately
3
/
32
in
.
±
1
/
32
further
than
right
hand
contact
.
least
3
/
16
in
.
,
the
main
contacts
gap
at
least
1
/
4
in
.
ADJUSTING
CONTACT
WIPE
AND
PRESSURE
(
Pig
.
6
)
NOTE
:
If
the
proper
contact
pressure
does
not
exist
when
the
contact
wipe
is
within its
limits
,
the
stationary
contacts
springs
should be
replaced
.
NOTE
:
This
check
can
best be
made
by
means
of
the mainte
-
nance
handle
,
with
the
safety
pin
restraining
the
closing
springs
.
1
.
To
obtain
proper
contact
wipe
and
pressure
on
the
center
pole
,
di
-
mension
"
A
”
should
be
increased
to
increase
wipe
and
decreased
to
de
-
crease
wipe
.
CONTACT
SEQUENCE
(
Pig
.
6
)
On
the horizontal
plane
,
the
dif
-
ference
in
the
making
of
the
arcing
contacts
on
the
same
pole
must
be
no
greater
than
1
/
32
in
.
;
the difference
between
arcing
contacts
on
separate
poles
1
/
16
in
.
If
it
is
desired
to
ad
-
vance
or
retard the
closing
of
the
main
contacts
of
a
pole
,
loosen the bolts
holding
the
adjustment
plate
(
10
A
)
of
that
pole
and
slide
plate
to
the
left
to
advance
contact
closing
,
or
to
the
right
to
retard
contact
closing
.
Make
this
adjustment
on
the
outer
poles
,
us
-
ing
the
center
pole
as
a
reference
.
Upon
retightening
adjustment
plate
bolts
,
make
sure
the
locking
tabs
are
turned
up
around bolt
heads
,
locking
the
bolts
securely
in
place
.
If
the
gap
is
under the
required
mini
-
mum
,
it
is
usually
possible
to
form
the
arcing
contacts
and
obtain
the
re
-
quired
dimensions
.
To
form
the
con
-
tacts
,
place
apiece
of
conduit
approxi
-
mately
two
feet
long
,
over
the
contact
and
form
the
contact
either
forward
or
backward
.
If
the
proper
dimensions
are
still
not
obtained
the movable
arc
-
ing
contacts
should be
replaced
.
2
.
To
change
dimension
MA
”
re
-
move
the
clevis
pin
(
14
)
and
rotate
the
clevis
as
necessary
.
3
.
To
prevent
overstressing
the
clevis threads
(
13
)
dimension
tTA
"
should
not
exceed
3
/
16
in
.
and
space
"
A
"
should
be filled
with
shims
to
0.005
in
.
of
being
solid
.
4
,
With
the
proper
center
pole
wipe
obtained
,
moving
the crossbar
adjust
-
ing
plate
(
10
A
)
on
the
center
pole
to
the
right
will
simultaneously
increase
the
wipe
on
both
outside
poles
;
moving
the
adjusting
plate
to
the
left will
have the
reverse
effect
.
If
it
has been
necessary
to
make
any
adjustments
while
obtaining
proper
contact
sequence
,
the
contact
wipe
and
pressure
must
be
checked
,
and
adjusted
,
if
necessary
.
5
,
To
increase the
wipe
on
either
outside
pole
individually
,
move
the
crossbar
adjusting
plate
of
that
pole
to
the
left
;
to
decrease
the
wipe
move
the
adjusting
plate
to
the
right
.
CONTACT
GAP
(
Fig
.
6
)
Contact
sequence
in
the vertical
plane
should
be
such
that
when the
arc
-
ing
contacts
are
just
touching
,
the
in
-
termediate
contact
gap
should
be
at
When
the breaker is
open
,
the
gap
between the movable
and
stationary
contacts
should
be
between
2
5
/
8
in
.
\
4
Courtesy of NationalSwitchgear.com

GE
/
-
74600
low
-
vo
/
foya
Power
Circuit
Broofrors
.
28
1
.
Screw
2
.
Stationary
Arcing
Contact
Pin
(
Stationary
Arcing
Contact
)
4
.
Movable
Arcing
Contact
5
.
Braid
5
A
.
Stationary
Intermediate
Contact
6
.
Movable
Main
Contact
7
.
Shouldered
Pin
Pin
(
Arcing
Contact
Link
)
Insulating
Link
Pin
(
Insulating
Link
)
10
A
,
Adjusting
Plate
11
.
Pin
(
Side
Link
)
11
A
.
Buffer
Spacers
12
.
Link
13
.
Clevis
14
.
Clevis
Pin
14
A
,
Opening
Spring
1
5
.
Lower
Stud
Pole
Unit
Base
17
.
Spring
(
Main
Movable
Contact
)
18
.
Pin
(
Movable
Main
Contact
)
19
.
Pin
(
Movable
Arcing
Contact
)
20
.
Side
Link
20
A
.
Contact
Stop
21
.
Spring
(
Stationary
Main
Contact
)
Spring
(
Stationary
Arcing
Con
-
tact
)
23
.
Upper
Stud
24
.
Pin
(
Stationary
Main
Contact
)
25
.
Stationary
Main
Contact
Screw
27
.
Screw
28
.
Stop
27
26
3
.
25
24
23
8
.
22
9
.
10
.
2
!
5
*
20
A
_
—
'
20
16
.
10
I
0
A
11
HA
12
13
22
.
14
I
4
A
26
.
)
Pole
unit
assembly
—
AK
-
50
Fig
.
6
.
and
2
3
/
4
in
.
The
gap
may
be ad
-
justed
by
varying
the number
of
buffer
spacers
(
11
A
)
on
the
cross
-
bar
.
The
locking
nuts
on
the
buffer bolts should
be locked
in
such
a
position
that
the
buffer bolt
may
be rotated
freely
.
REPLACEMENT OF
CONTACTS
(
Fig
.
6
)
Stationary
Arcing
Contacts
(
2
,
Fig
.
6
)
a
Fig
.
7
)
1
.
Remove
the
upper
plate
by
re
-
moving
two
screws
(
1
)
.
On
the
AK
-
75
and
-
100
remove
the
top
contact
block
(
25
,
Fig
.
7
)
and
remove
insulation
(
3
,
Fig
.
7
)
.
2
.
Remove
screws
from
shunting
braids
(
5
)
.
3
.
Remove
pin
(
3
)
freeing
the
sta
-
s
^
^
-
dtionary
contacts
and
springs
(
22
)
.
4
.
Install
new
springs
and
station
-
2
.
Remove
screws
(
27
)
and
remove
bracket which holds
pin
(
24
)
in
place
.
5
.
Adjust
contact
wipe
and
pres
-
(
See
ADJUSTING
CONTACT
sure
.
WIPE
AND
PRESSURE
.
)
3
.
Remove
main
-
and
intermediate
-
contact
stop
(
20
A
)
which
holds
the lower
part
of
stationary
contact
.
Removal
will
be
facilitated
if
the
force
on
the
contact
springs
(
21
)
is
neutralized
.
This
can
be
accomplished
by
operat
-
ing
the
breaker
with
the
maintenance
handle
,
with the
safety
pin
in
place
,
until
the
load
on
the
contact
stop
is
relieved
.
Movable
Arcing
Contacts
(
Fig
.
6
)
The
movable
arcing
contacts
(
4
)
should
be
replaced
when the
stationary
arcing
contacts
are
replaced
.
1
.
Separate
the
front frame
from
the
back
frame
as
described
under
SEPA
-
RATION OF
FRONT
AND
REAR
FRAMES
.
4
.
Loosen
the
hardware which
fastens
the
upper
stud
to
the
pole
unit
base
until
the
contact
-
spring
load
on
pin
(
24
)
is
relieved
.
5
.
Remove
pin
(
24
)
and
screws
(
26
)
and
lift
out
contacts
.
2
.
Remove
pins
(
8
)
and
(
19
)
and
withdraw the
contacts
.
3
,
Reassemble
parts
in
reverse
order
.
Stationary
,
Intermediate and
Main
Contacts
(
Fig
.
6
)
1
.
Remove
stationary
arcing
con
-
6
.
Reassemble
contacts
in
reverse
order
,
being
careful
to
replace
the
intermediate
contact
in
the
proper
£
4
i
-
i
_
Courtesy of NationalSwitchgear.com