GE AK-50 Series Technical specifications

This manual suits for next models

43

Table of contents

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GEK

-

7303

C

*

A

Lowvoltage

Power

Circuit

Breakers

Maintenance

Instructions

'

Supersedes

GEH

-

1798

A

GEH

-

1799

GEH

-

1823

G

El

-

5021

OA

GEI

-

50211

GEI

-

50212

A

GEI

-

57077

G

El

-

74600

Types

AK

-

50

/

75

/

100

,

AKT

-

50

,

AKU

-

50

,

and

AKF

-

2

C

/

2

D

/

2

E

NOTE

:

To

be

used

in

conjunction

with

GEl

-

86135

which

covers

Types

AK

-

75

/

100

breakers

with

ECS

and

SST

trip

devices

.

ELECTRIC

GENERAL

Courtesy of NationalSwitchgear.com

CONTENTS

3

INTRODUCTION

3

OPERATION

MANUAL

CLOSING

.

.

.

MANUAL

MAINTENANCE

CLOSING

OF

ELECTRICAL

BREAKERS

ELECTRICAL

CLOSING

.

QUICK

CLOSE

FOR

ELECTRICAL

BREAKERS

ELECTRICAL

TRIPPING

.

..

3

4

4

4

5

5

MAINTENANCE

INSERTING

SAFETY

PIN

-

AK

-

50

,

AK

-

75

AND

AK

-

100

INSPECTION

TROUBLE

SHOOTING

LUBRICATION

SEPARATION

OF

FRONT

AND

REAR

FRAMES

5

5

6

7

7

7

BASIC

BREAKER

COMPONENTS

ARC

QUENCHERS

POLE

UNIT

ASSEMBLY

OPERATING

MECHANISMS

QUICK

CLOSE

BREAKER

ADJUSTMENTS

AUXILIARY

SWITCH

7

8

13

16

11

23

ELECTRICAL

CLOSING

DEVICES

AND

CONTROLS

CLOSING

SWITCH

CUT

-

OFF

SWITCHES

CONTROL

RELAY

23

23

23

23

PROTECTIVE

DEVICES

STATIC

TIME

DELAY

UNDERVOLTAGE

TRnPING

DEVICE

INSTANTANEOUS

UNDER

VOLTAGE

TRIPPING

DEVICE

.

.

..

UNDERVOLTAGE

LOCKOUT

DEVICE

.

.

.

.

.

.

.

DIRECT

-

ACTING

TRIPPING

DEVICE

-

EC

-

1

B

SERIES

OVERCURRENT

TRIPPING

DEVICE

EC

-

1

SERIES

OVERCURRENT

TRIPPING

DEVICE

EC

-

2

/

EC

-

2

A

.

.

.

REVERSE

CURRENT

TRIPPING

DEVICE

(

AK

-

50

ONLY

)

POWER

SENSOR

TRIP

..

.

.

SELECTIVE

TRIPPING

23

25

25

26

29

31

33

33

39

42

BREAKER

ACCESSORIES

PRIMARY

DISCONNECTS

SECONDARY

DISCONNECTS

DRAWOUT

MECHANISMS

SHUNT

TRIPPING

DEVICE

BELL

ALARM

AND

LOCKOUT

DEVICE

OPEN

FUSE

LOCKOUT

DEVICE

42

42

43

44

44

45

47

MISCELLANEOUS

TOOLS

RENEWAL

’

PARTS

47

47

These

instructions

do

not

purport

to

cover

all

details

or

variations

in

equipment

nor

to

provide

for

every

possible

contingency

to

be

met

in

connection

with

installation

,

operation

or

maintenance

.

Should

further

information

be

desired

or

should

particular

problems

arise

which

are

not

covered

sufficiently

for

the

purchaser

’

s

purposes

,

the

matter

should

be

referred

to

the

General

Electric

Company

.

Courtesy of NationalSwitchgear.com

LOW

-

VOLTAGE

POWER

CIRCUIT

BREAKERS

Types

AK

-

2

/

3

/

2

A

/

3

A

-

50

/

50

S

AKT

-

2

/

3

/

50

/

50

S

AK

-

2

/

3

/

2

A

/

3

A

-

75

/

75

S

AKU

-

2

/

3

/

2

A

/

3

A

-

50

/

50

S

AK

-

2

/

3

/

2

A

/

3

A

-

100

/

100

S

AKF

-

2

C

/

2

D

/

2

E

OPERATION

INTRODUCTION

MANUAL

CLOSING

For

a

description

of

manual

closing

,

refer

to

the

section

of

these

instructions

entitled

CLOS

-

ING

THE

BREAKER

-

MANUALLY

OPERATED

AK

-

50

and

section

entitled

AK

-

50

-

75

AND

-

100

STORED

ENERGY

MANUAL

MECHANISM

,

both

under

OPERATING

MECHANISMS

.

The

instructions

contained

herein

are

intended

to

aid

in

the

maintenance

and

repair

of

basic

breakers

and

accessories

for

AK

-

50

-

75

-

100

Low

Voltage

Power

Circuit

Breakers

.

The

basic

AK

-

50

,

AK

-

75

and

AK

-

100

breaker

designs

have

been

expanded

to

include

special

designs

for

specific

applications

.

These

design

extensions

have

caused

variations

in

the

nomen

-

clature

including

the

following

:

AK

-

2

-

50

,

AK

-

2

-

75

or

AK

-

2

-

100

-

Basic

standard

design

of

breaker

for

stationary

mounting

or

for

drawout

use

in

AKD

type

equipment

.

AK

-

2

A

-

50

,

AK

-

2

A

-

75

,

AK

-

2

A

-

100

-

The

A

indicates

it

has

mounting

features

for

AKD

-

5

type

equipment

.

AK

-

2

-

50

S

,

AK

-

2

-

75

S

,

AK

-

2

-

100

S

-

The

S

indicates

breaker

is

equipped

with

a

quick

-

close

mechanism

which

provides

closing

times

of

approximately

5

cycles

(

.

08

seconds

)

.

AKU

-

2

-

50

fuse

breaker

combination

.

T

_

.

CLOSING

|

“

T

SWITCH

—

—

II

—

11

REMOTE

CLOSE

L

T

*

‘

F

:

|

=

TRIP

I

G

_

IUi

oo

£

C

<

G

±

zF

z

-

i

oo

o

>

L

TRIP

COIL

X

M

LEGEND

*

CLOSING

MOTOR

*

RELAY

COIL

+

*

RELAY

CONTACT

FftG

«

=

MECHANICALLY

OPERATED

SWITCHES

+

=

NORMALLY

OPEN

SWITCH

CONTACTS

£

=

NORMALLY

CLOSED

SWITCH

CONTACTS

L

-

AUXILIARY

SWITCH

CONTACT

®

X

The

U

indicates

an

internal

SIMPLIFIED

ELEMENTARY

DIAGRAM

INTERNAL

WIRING

AK

—

50

,

75

,

AND

100

AKF

-

2

C

,

AKF

-

2

D

,

AKF

-

2

E

switches

for

use

in

controlling

shunt

fields

of

synchronous

motors

and

generators

.

AK

-

2

-

50

H

rupting

rating

has

been

increased

to

the

75

,

000

amp

.

class

.

AK

-

2

-

50

C

,

AK

-

2

-

75

C

-

The

C

indicates

the

interrupting

rating

has

been

increased

to

the

100

,

000

amp

.

class

.

AKT

-

2

-

50

continuous

rating

of

2000

amps

.

AK

-

3

-

50

,

AK

-

3

-

75

,

AK

-

3

-

100

indicates

the

breaker

is

equipped

with

the

Power

Sensor

Overcurrent

Trip

Device

.

AK

-

2

-

50

X

-

The

X

indicates

the

breaker

has

very

special

features

or

it

includes

two

or

more

of

the

design

extensions

previously

described

.

When

contacting

the

factory

,

it

is

important

to

furnish

the

complete

nameplate

information

.

Are

field

Fig

.

1

.

The

H

indicates

the

inter

-

CLOSING

SWITCH

T

J

_

REMOTE

=

F

CLOSE

ih

-

i

.

v

T

-

E

T

-

G

TD

fi

°

o

<

-

»

>

X

±

F

=

TF

=

4

=

X

W

The

T

indicates

increased

\

cc

<

M

)

r

The

3

LEGEND

CC

-

CLOSING

RELAY

COIL

D

-

CLOSING

RELAY

CONTACTS

E

-

ANTI

-

PUMP

RELAY

CONTACTS

FAG

-

MECHANICALLY

OPERATED

SWITCHES

-

AUXILIARY

SWITCH

CONTACTS

-

CLOSING

MOTOR

-

ANTI

-

PUMP

RELAY

COIL

*

-

CONTROL

RELAY

CONTACTS

X

-

CONTROL

RELAY

COIL

4

:

-

NORMALLY

OPEN

SWITCH

CONTACTS

f

-

NORMALLY

CLOSED

SWITCH

CONTACTS

9

SIMPLIFIED

ELEMENTARY

DIAGRAM

INTERNAL

WIRING

QUICK

CLOSE

BREAKER

Fig

.

1

A

.

3

Courtesy of NationalSwitchgear.com

GEK

-

7303

Low

Voltage

Power

Circuit

Breakers

MANUAL

MAINTENANCE

CLOSING

OF

ELECTRICAL

BREAKERS

An

electrical

breaker

may

be

closed

manually

by

means

of

the

maintenance

handle

furnished

with

the

breaker

.

reach

the

fully

charged

position

,

the

mechanically

operated

switches

operate

,

reversing

their

contacts

.

Upon

operation

of

these

switches

the

motor

is

stopped

by

the

opening

of

the

G

switch

.

The

closing

of

the

F

switch

prepares

the

breaker

for

a

closing

operation

.

To

observe

the

operation

of

the

breaker

with

-

out

power

,

with

the

breaker

open

and

springs

discharged

,

proceed

as

follows

:

1

.

Charge

the

closing

spring

with

the

main

-

tenance

handle

(

1

,

Fig

.

3

)

until

the

indica

-

tor

reads

"

charged

”

.

2

.

Continue

to

operate

the

maintenance

handle

until

the

breaker

closes

.

3

.

Open

the

breaker

by

pushing

the

trip

button

(

4

,

Fig

.

2

)

.

ELECTRICAL

CLOSING

The

electrical

control

system

is

comprised

of

an

X

relay

,

two

double

contact

mechanically

operated

switches

(

F

and

G

)

,

a

push

button

closing

switch

and

any

means

for

remote

closing

which

the

user

may

incorporate

into

the

system

.

When

voltage

is

first

applied

to

the

breaker

,

(

before

any

closing

signal

is

given

)

the

motor

is

energized

through

two

of

the

X

relay

contacts

and

the

two

G

switch

contacts

.

The

motor

then

compresses

the

closing

springs

to

the

"

pre

-

charged

"

position

at

which

point

the

mechanically

operated

F

and

G

switches

are

operated

.

This

opens

the

G

contacts

,

stopping

the

motor

,

and

closes

the

F

contacts

,

which

readies

the

system

for

the

actual

closing

of

the

breaker

.

When

the

push

button

or

remote

switch

signals

for

a

closing

operation

,

the

X

relay

coil

is

energized

,

operating

the

X

contacts

.

This

seals

in

the

X

relay

and

energizes

the

motor

once

again

and

the

closing

operation

takes

place

.

QUICK

CLOSE

FOR

ELECTRICAL

BREAKERS

Functionally

,

the

quick

close

mechanism

differs

from

the

standard

electrical

mechanism

in

that

the

pre

-

charge

operation

is

extended

to

completely

charge

the

closing

springs

.

At

the

end

of

the

charg

-

ing

operation

,

which

takes

approximately

5

seconds

,

a

latch

plate

engages

the

prop

roller

to

prevent

the

closing

springs

from

discharging

.

With

the

closing

springs

fully

charged

the

breaker

is

ready

for

a

closing

operation

upon

release

of

the

prop

roller

.

This

may

be

accom

-

plished

either

manually

,

by

depressing

the

closing

lever

on

the

breaker

,

or

electrically

by

closing

the

remote

closing

switch

.

Upon

the

release

of

the

prop

roller

the

closing

springs

discharge

and

close

the

breaker

in

the

same

manner

as

on

the

standard

electrical

breaker

.

Fig

.

2

(

8039671

)

Front

view

of

AK

-

2

-

50

breaker

1

.

Auxiliary

Switch

2

.

Position

Indicator

3

.

Relay

4

.

Manual

Trip

Button

5

.

Shaft

for

Manual

Mainte

-

nance

Closing

Handle

6

.

Spring

Charged

-

Discharged

Indicator

7

.

Motor

Cut

-

off

Switches

8

.

Arc

Quenchers

A

closing

signal

now

given

energizes

the

control

relay

X

whose

contacts

close

and

complete

the

circuit

through

the

closing

relay

coil

.

With

the

closing

relay

coil

energized

the

breaker

closes

as

described

above

.

At

the

same

time

the

closing

relay

contact

closes

to

energize

the

anti

-

pump

relay

causing

its

contacts

to

reverse

providing

the

anti

-

pump

feature

.

When

the

breaker

closes

,

the

mechanical

opera

-

ted

G

switches

close

to

energize

the

motor

again

and

the

F

switches

open

and

de

-

energize

the

con

-

trol

relay

from

being

energized

until

the

breaker

is

tripped

open

.

With

the

G

switches

closed

,

the

motor

charges

the

closing

springs

ready

for

the

next

closing

operation

.

With

control

voltage

applied

,

the

motor

is

energized

through

the

G

switch

contacts

,

and

charges

the

closing

springs

.

When

the

springs

4

Courtesy of NationalSwitchgear.com

Low

Voltage

Power

Circuit

Breakers

GEK

-

7303

ELECTRICAL

TRIPPING

The

breaker

may

be

tripped

electrically

by

any

of

the

electrical

tripping

devices

described

in

these

instructions

,

tripped

by

the

automatic

overcurrent

or

reverse

current

tripping

devices

,

if

so

equipped

,

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

rotating

the

trip

shaft

and

displacing

the

trip

latch

.

The

most

commonly

used

tripping

device

is

the

shunt

trip

device

connected

in

the

control

circuit

as

shown

in

Fig

.

1

.

When

a

tripping

signal

is

given

,

the

shunt

trip

coil

is

energized

through

a

norftially

-

open

auxiliary

switch

"

a

”

contact

,

thus

tripping

the

breaker

.

The

breaker

may

also

be

All

MAINTENANCE

BEFORE

INSPECTION

OR

ANY

MAINTENANCE

WORK

IS

DONE

BE

SURE

THAT

THE

BREAKER

IS

IN

THE

OPEN

POSITION

.

ALL

ELECTRICAL

POWER

,

BOTH

PRIMARY

AND

CONTROL

SOURCES

,

SHOULD

ALSO

BE

DISCONNECTED

.

Fig

.

3

(

8039670

)

View

showing

operation

of

AK

-

2

-

50

breaker

with

manual

maintenance

handle

and

installation

of

safety

pin

Warning

:

ergy

closing

mechanisms

,

care

must

be

taken

when

the

circuit

breaker

is

being

installed

and

when

any

inspection

or

maintenance

work

is

being

done

so

that

the

breaker

is

in

the

open

position

and

the

closing

springs

are

being

restrained

by

the

safety

pin

.

The

proce

-

dure

for

inserting

the

safety

pin

is

given

below

.

INSERTING

SAFETY

PIN

AK

-

50

,

-

75

and

-

100

(

Fig

.

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

)

.

Continue

to

operate

the

maintenance

handle

,

clos

-

ing

the

breaker

.

This

is

done

so

that

the

safety

pin

takes

the

spring

force

.

To

install

the

safety

pin

of

the

manual

stored

-

energy

mechanism

refer

to

the

section

entitled

STORED

-

ENERGY

MANUAL

MECHANISM

on

page

17

of

these

instructions

.

With

the

safety

pin

restraining

the

closing

spring

force

,

the

contacts

will

close

slowly

when

the

breaker

is

manually

operated

allowing

the

operation

of

the

mechanism

and

the

contact

align

-

ment

to

be

visually

observed

.

On

breakers

employing

stored

-

en

-

1

.

Manual

maintenance

Handle

2

.

Push

Rod

3

.

Safety

Pin

INSPECTION

Periodic

inspection

of

the

circuit

breaker

is

recommended

at

least

once

a

year

.

More

fre

-

quent

inspections

are

recommended

if

severe

load

conditions

,

dust

,

moisture

or

other

unfavor

able

conditions

exist

,

of

the

breaker

,

including

contacts

and

arc

quenchers

,

should

always

be

made

after

the

breaker

has

in

-

terrupted

a

short

-

circuit

.

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

mechanism

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

arrangements

be

made

to

open

and

close

it

several

times

in

succession

,

preferably

under

load

.

A

complete

inspection

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

Hie

push

rod

.

If

overheating

,

not

caused

by

overcurrent

,

is

observed

,

a

complete

inspection

of

the

breaker

should

be

made

including

connections

and

contacts

.

5

Courtesy of NationalSwitchgear.com

GEK

-

7303

Low

Voltage

Power

Circuit

Breakers

TROUBLE

SHOOTING

1

REMEDY

CAUSE

TROUBLE

Overheating

Contacts

not

aligned

.

Contacts

dirty

,

greasy

or

coated

with

dark

film

.

Adjust

contacts

.

Clean

contacts

.

Replace

contacts

.

Clean

surfaces

of

current

-

carrying

parts

.

Relocate

or

provide

adequate

enclosure

.

Increase

capacity

of

bus

or

cable

.

Tighten

,

but

do

not

exceed

,

elastic

limit

of

bolts

or

fittings

.

Check

breaker

application

or

modify

circuit

by

decreasing

load

.

Provide

adequate

ventilation

.

Correct

bus

or

cable

arrangement

.

Contacts

badly

burned

or

pitted

.

Current

-

carrying

surfaces

dirty

.

Corrosive

atmosphere

.

Insufficient

bus

or

cable

capacity

.

Bolts

and

nuts

at

terminal

connections

not

tight

.

Current

in

excess

of

breaker

rating

.

Excessive

ambient

temperature

.

Inductive

heating

.

Failure

to

Trip

AK

-

2

Breakers

Travel

of

tripping

device

does

not

provide

positive

release

of

tripping

latch

.

Worn

or

damaged

trip

unit

parts

.

Binds

in

overcurrent

trip

device

.

Re

-

adjust

or

replace

tripping

device

.

Replace

trip

unit

.

Replace

overcurrent

trip

device

.

Loose

or

Disconnected

Power

Sensor

Disconnect

Plugs

.

Tighten

or

Reconnect

Disconnect

Plugs

.

Tighten

or

Reconnect

Tap

Connections

.

Failure

to

Trip

AK

-

3

Breakers

Loose

or

Broken

Power

Sensor

Coil

Tap

Connections

.

)

Check

application

of

overcurrent

trip

device

.

Check

application

of

overcurrent

trip

device

.

Replace

overcurrent

trip

device

.

False

Tripping

AK

-

2

Breakers

Overcurrent

pick

up

too

low

.

Overcurrent

time

setting

too

short

.

Bind

in

overcurrent

trip

device

.

Tighten

Thumb

Screw

on

Desired

Setting

.

Captive

Thumb

Screw

on

Power

Sensor

Loose

Fail

-

Safe

Circuitry

Reverts

Characteristic

to

Minimum

Setting

and

Maximum

Time

Delay

.

Tap

Setting

Dial

on

Power

Supply

Incorrectly

Set

.

External

Ground

Sensor

Coil

Improperly

Connected

.

Set

Dial

to

Correspond

with

Power

Sensor

Coil

Tap

.

Refer

to

Fig

.

40

Page

38

for

Polarity

and

Connections

.

Check

Continuity

of

Shield

and

Conductors

Connecting

the

External

Ground

Sensor

Coil

False

Tripping

AK

-

3

Breakers

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

.

Hardened

or

gummy

lubricant

.

Safety

pin

left

in

push

rod

..

Motor

burned

out

.

Adjust

latch

.

Replace

spring

.

Clean

bearing

and

latch

surfaces

.

Remove

safety

pin

.

Replace

motor

.

Replace

or

adjust

faulty

device

.

Faulty

control

circuit

component

.

Improper

contact

sequence

(

main

contacts

not

sufficiently

parted

when

arcing

contacts

part

)

.

Short

-

circuit

current

level

above

inter

-

rupting

rating

of

breaker

.

Burned

Main

Contacts

Increase

arcing

contact

wipe

.

Adjust

contact

sequence

by

raising

or

lower

-

ing

main

movable

contact

pivot

block

.

Requires

system

study

and

possible

replacement

with

breaker

having

ade

-

quate

interrupting

capacity

.

Replace

stationary

contact

springs

and

dress

up

or

replace

contacts

.

J

Loss

of

contact

wipe

or

pressure

.

6

Courtesy of NationalSwitchgear.com

Low

Voltage

Power

Circuit

Breakers

GEK

-

7303

5

.

Remove

the

auxiliary

switch

operating

rod

(

&

,

Fig

.

20

)

.

At

all

times

it

is

important

not

to

permit

pencil

lines

,

paint

,

oil

or

other

foreign

mater

-

ials

to

remain

on

the

insulating

surfaces

of

the

breaker

as

they

may

cause

low

resistance

between

points

of

different

potential

and

result

in

eventual

electrical

breakdown

.

6

.

Check

along

the

trip

shaft

for

a

mech

-

anical

interference

or

connection

between

the

overcurrent

trip

device

and

the

trip

paddles

.

Remove

mechanical

connection

if

present

,

or

if

interference

exists

,

use

extreme

care

when

removing

or

re

-

assembling

front

and

back

frames

to

avoid

mechanical

breakage

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

.

NOTE

:

be

fastened

to

a

suitable

maouting

base

with

the

front

frame

supported

by

a

sling

or

hook

as

the

bolts

are

being

installed

.

The

breaker

should

be

operated

several

times

at

a

rated

voltage

to

assure

that

the

control

circuits

are

properly

connected

and

that

all

electrical

attachments

are

functioning

properly

.

A

complete

contact

inspection

,

including

con

-

tact

wipe

and

pressure

,

should

be

made

at

regu

-

lar

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

.

Arc

-

ing

contacts

and

arc

quencher

barriers

should

be

replaced

when

they

are

eroded

to

half

their

original

thickness

.

It

is

recommended

that

the

breaker

BASIC

BREAKER

COMPONENTS

ARC

QUENCHERS

(

Fig

.

4

and

5

)

The

arc

quenchers

should

be

inspected

at

the

If

the

barriers

are

LUBRICATION

regular

inspection

period

,

cracked

or

eroded

to

one

-

half

their

original

thickness

,

they

should

be

replaced

.

In

general

,

the

circuit

breaker

requires

mod

-

Mechanical

bearing

points

erate

lubrication

,

and

sliding

surfaces

should

be

lubricated

at

the

regular

inspection

periods

with

a

thin

film

of

G

-

E

Lubricant

D

50

H

15

.

Sliding

silver

plated

con

-

tact

surfaces

should

be

lubricated

with

G

-

E

Lub

-

ricant

D

50

H

47

.

Hardened

grease

and

dirt

should

be

removed

from

latch

and

bearing

surfaces

by

using

kerosene

.

ALL

EXCESS

LUBRICANT

SHOULD

BE

REMOVED

TO

AVOID

ANY

ACCUMULATION

OF

DIRT

OR

DUST

.

REPLACEMENT

—

AK

BREAKERS

Be

sure

the

breaker

is

open

.

1

.

2

.

Remove

the

channel

-

shaped

retaining

bar

by

removing

two

screws

and

two

nuts

.

3

.

Lift

the

quenchers

clear

of

the

movable

arcing

contacts

.

4

.

During

replacement

be

careful

not

to

overtighten

the

screw

which

secure

the

channel

-

shaped

retaining

bar

.

Overtightening

the

screws

will

bow

the

bar

and

leave

the

center

arc

quen

-

cher

loose

.

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

.

On

drawout

breakers

,

the

contact

surface

of

the

disconnect

studs

should

be

greased

with

G

-

E

Grease

Specification

D

50

H

47

.

SEPARATION

OF

FRONT

AND

REAR

FRAMES

To

repair

or

replace

contacts

,

operating

mech

-

anism

,

or

the

overcurrent

devices

,

the

front

frame

must

be

separated

from

the

back

frame

.

To

separate

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

the

breaker

)

from

the

outside

pole

units

.

3

.

Remove

the

clevis

pin

(

14

,

Fig

.

6

)

(

13

,

Fig

.

7

)

from

the

center

pole

unit

.

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

.

REPLACEMENT

—

AKF

BREAKERS

The

center

-

pole

arc

quencher

of

these

breakers

is

similar

to

the

arc

quenchers

of

the

standard

breakers

and

is

replaced

in

a

similar

manner

,

except

that

the

breaker

must

be

closed

.

With

the

breaker

closed

the

center

-

pole

contacts

are

open

and

the

arc

quencher

can

be

removed

.

Replace

the

outer

-

pole

arc

quenchers

of

the

Type

AKF

breaker

as

follows

:

1

.

Be

sure

the

breaker

is

open

.

2

.

Remove

the

two

channel

-

shaped

retaining

bars

which

bear

against

the

front

of

the

arc

quenchers

by

removing

four

screws

,

two

on

each

side

.

3

.

Lift

the

arc

quenchers

clear

of

the

movable

arcing

contacts

.

4

.

Replace

arc

quenchers

and

insert

the

four

screws

holding

the

retaining

bars

in

position

.

7

Courtesy of NationalSwitchgear.com

GEK

-

7303

Low

Voltage

Power

Circuit

Breakers

9

8

7

6

Fig

.

4

(

8014830

)

Disassembly

of

arc

quenchers

-

standard

breaker

and

AKF

center

pole

.

6

.

Muffler

7

.

Compound

Support

8

.

Steel

Back

Plate

9

.

Spacer

Block

1

.

Stud

2

.

Cap

3

.

Side

Barrier

4

.

Pocket

Barrier

5

.

Inner

Barrier

DISASSEMBLY

—

AK

AND

AKF

CENTER

POLE

(

Fig

.

4

)

The

following

instructions

apply

to

both

tne

Type

AK

and

AKF

breaker

center

poles

.

3

.

Remove

bolt

fastening

cap

(

4

)

and

barrier

plate

assembly

.

4

.

Barrier

plates

may

now

be

lifted

from

as

-

sembly

for

inspection

.

5

.

In

reassembling

,

make

sure

components

are

positioned

so

that

holes

for

self

-

tapping

hard

-

ware

are

in

line

.

Do

not

strip

threads

in

compound

by

overstressing

screws

.

1

.

Remove

arc

quenchers

(

see

REPLACE

-

MENT

)

.

2

.

Remove

screws

holding

spacer

block

(

9

)

.

3

.

Remove

spacer

block

,

steel

back

plate

(

8

)

,

and

compound

support

(

7

)

.

4

.

Rock

muffler

(

6

)

slightly

and

remove

.

The

inner

barriers

(

5

)

can

now

be

removed

for

inspection

.

5

.

Remove

nut

and

withdraw

stud

(

1

)

.

6

.

Remove

cap

(

2

)

.

The

side

(

3

)

and

pocket

(

4

)

barriers

should

be

free

.

7

.

Reassemble

and

replace

the

arc

quencher

in

the

reverse

order

.

Tighten

the

fastenings

after

replacement

.

POLE

UNIT

ASSEMBLY

(

Fig

.

6

)

NOTE

:

The

text

and

part

identification

numbers

contained

in

this

section

apply

to

illustrations

covering

the

AK

-

50

breaker

.

The

same

text

is

applicable

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

identified

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

.

Fig

.

8

and

9

,

pole

unit

assemblies

mounted

on

back

frame

assemblies

.

See

DISASSEMBLY

—

AKF

OUTER

POLES

(

Fig

.

5

)

1

.

Remove

arc

quenchers

(

see

above

)

and

lay

on

sides

on

a

flat

surface

.

The

stationary

arcing

-

contact

assembly

con

-

sists

of

a

set

of

parallel

contact

fingers

(

2

)

,

pin

(

3

)

,

and

compression

springs

(

22

)

,

which

provide

continuous

contact

pressure

for

the

full

2

.

Remove

hardware

from

one

side

of

arc

quencher

as

indicated

in

Fig

.

5

.

8

Courtesy of NationalSwitchgear.com

GEK

-

7303

Low

Voltage

Power

Circuit

Breakers

I

*

I

I

J

1

2

a

Figo

5

(

8019408

)

Disassembled

arc

quencher

-

AKF

outer

poles

.

1

.

Muffler

Assembly

2

.

Spacer

Block

3

o

Inner

Barrier

4

.

Cap

5

.

Intermediate

Barrier

6

.

Outer

Barrier

7

.

Side

Plate

Steel

springs

(

5

)

shunt

travel

of

the

contacts

,

the

pivot

pin

to

prevent

possible

pitting

at

the

pivot

point

when

interrupting

high

currents

.

On

earlier

model

breakers

flexible

braid

leads

were

used

.

In

order

to

function

properly

,

a

definite

amount

of

contact

pressure

and

contact

wipe

must

exist

between

the

movable

and

stationary

contacts

.

Table

I

gives

the

figures

for

contact

pressure

and

contact

wipe

.

Both

wipe

and

pressure

should

be

checked

during

the

regular

inspection

period

.

MEASURING

CONTACT

WIPE

(

Fig

.

6

)

1

.

Remove

arc

quenchers

(

see

REPLACEMENT

under

ARC

QUENCHER

)

.

2

.

With

the

breaker

open

,

measure

the

hori

-

zontal

distance

from

the

edge

of

the

stationary

contact

to

the

stationary

block

behind

it

.

(

"

B

”

dim

.

for

arcing

contacts

,

”

C

"

dim

.

for

main

contacts

)

.

The

movable

arcing

-

contact

assembly

consists

of

parallel

contact

arms

(

4

)

carried

on

two

mov

-

able

pivot

pins

(

8

)

and

(

19

)

.

The

arcing

contacts

interleave

the

main

contacts

and

pivot

with

them

about

pin

(

19

)

.

This

relative

motion

is

obtained

by

linkages

from

the

upper

pin

(

7

)

to

the

breaker

mechanism

.

The

stationary

main

contact

assembly

includes

main

and

intermediate

contacts

.

The

intermediate

-

contact

surface

extends

beyond

the

main

contacts

and

will

,

therefore

,

make

before

the

main

contacts

and

break

after

the

main

contacts

.

The

number

of

contacts

for

each

breaker

rating

is

given

in

Table

I

.

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

.

3

.

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

)

,

connected

by

an

insulated

link

(

12

)

to

th

.

e

breaker

mechanism

.

In

addition

to

steel

springs

shunting

the

current

from

the

contact

directly

to

the

lower

contact

block

,

steel

springs

(

17

)

force

the

contacts

against

the

pins

to

prevent

pitting

at

the

pivot

point

.

The

movable

main

contact

assembly

also

contains

main

and

intermediate

contacts

.

MEASURING

CONTACT

PRESSURE

(

Fig

.

6

)

1

.

Remove

arc

quenchers

(

see

REPLACEMENT

UNDER

ARC

QUENCHER

)

.

2

.

Close

the

breaker

and

measure

dimension

”

BTT

.

3

.

Open

the

breaker

.

Place

a

push

-

type

scale

9

Courtesy of NationalSwitchgear.com

Low

Voltage

Power

Circuit

Breakers

GEK

-

7303

TABLE

I

Intermediate

Contacts

Arcing

Contacts

Main

Contacts

Pres

-

sure

in

Lbs

.

Wipe

No

.

of

Zontacts

Per

Pole

Wipe

No

.

of

Contacts

Per

Pole

Pres

-

sure

In

Lbs

.

Wipe

No

.

of

in

Contacts

Inches

/

Per

Pole

Pres

-

sure

in

Lbs

.

Breaker

Type

in

in

Inches

Inches

4

/

64

to

12

/

64

to

18

/

64

12

/

64

to

18

/

64

12

/

64

to

18

/

64

12

/

64

to

18

/

64

12

/

64

to

18

/

64

12

/

64

to

18

/

64

12

/

64

to

18

/

64

AK

-

50

for

AC

3

55

to

65

31

to

43

55

to

65

2

1

*

7

/

64

1

/

16

to

AK

-

50

for

DC

3

3

31

to

43

55

to

65

55

to

65

1

7

/

64

1

/

16

to

AK

-

75

for

AC

35

to

45

35

to

45

31

to

43

5

3

1

7

/

64

1

/

16

to

AK

-

75

for

DC

35

to

45

5

35

to

45

5

31

to

43

1

*

7

/

64

1

/

16

to

AK

-

100

for

AC

AK

-

100

for

DC

8

25

to

35

25

to

35

31

to

43

2

5

7

/

64

1

/

16

to

AKF

-

2

C

3

55

to

65

55

to

65

2

31

to

43

1

*

7

/

64

(

Outside

Poles

)

25

to

35

1

/

16

to

AKF

-

2

D

(

Outside

AKF

-

2

E

(

Poles

)

55

to

65

31

to

43

5

3

1

7

/

64

AKF

-

2

C

(

Field

AKF

-

2

D

Discharge

Contacts

)

28

/

64

to

40

/

64

0

10

to

16

0

2

*

*

*

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

.

against

the

stationary

arcing

contacts

at

a

point

measured

in

line

with

the

break

between

the

contact

stop

and

the

contact

pivot

block

.

Push

the

contact

backward

until

dimension

"

B

"

recorded

in

item

2

is

reached

.

effect

.

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

.

The

scale

should

then

be

read

.

4

.

If

the

pressure

is

not

within

the

require

-

ments

listed

on

TABLE

I

,

refer

to

the

section

of

these

instructions

dealing

with

ADJUSTING

CONTACT

WIPE

AND

PRESSURE

.

ADJUSTING

CONTACT

WIPE

AND

PRESSURE

(

Fig

.

6

)

1

.

To

obtain

proper

contact

wipe

and

pressure

on

the

center

pole

,

dimension

"

A

"

should

be

increased

to

increase

wipe

and

decreased

to

decrease

wipe

.

2

.

To

change

dimension

"

A

"

remove

the

clevis

pin

(

14

)

and

rotate

the

clevis

as

necessary

.

3

.

To

prevent

overstressing

the

clevis

threads

(

13

)

dimension

,

TAft

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

adjusting

plate

(

10

A

)

center

pole

to

the

right

will

simultaneously

in

-

crease

the

wipe

on

both

outside

poles

;

moving

the

adjusting

plate

to

the

left

will

have

the

reverse

If

the

proper

contact

pressure

NOTE

:

does

not

exist

when

the

contact

wipe

is

within

its

limits

,

the

stationary

contacts

springs

should

be

replaced

.

CONTACT

SEQUENCE

(

Fig

.

6

)

On

the

horizontal

plane

,

the

difference

in

the

making

of

the

arcing

contacts

on

the

same

pole

must

be

no

greater

than

1

/

32

in

.

;

the

difference

be

-

tween

arcing

contacts

on

separate

poles

1

/

16

in

.

If

it

is

desired

to

advance

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

,

using

the

center

pole

as

a

reference

.

Upon

retight

-

ening

adjustment

plate

bolts

,

make

sure

the

lock

-

ing

tabs

are

turned

up

around

bolt

heads

,

locking

the

bolts

securely

in

place

.

on

the

Contact

sequence

in

the

vertical

plane

should

be

such

that

when

the

arcing

contacts

are

just

touching

,

the

intermediate

contact

gap

should

be

10

Courtesy of NationalSwitchgear.com