Ge Ak-50 series Technical specifications

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

5

MAINTENANCE

INSERTING

SAFETY

-

AK

-

50

,

AK

-

75

AND

AK

-

100

INSPECTION

TROUBLE

SHOOTING

LUBRICATION

SEPARATION

OF

FRONT

AND

REAR

FRAMES

5

6

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

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

26

29

31

33

39

42

BREAKER

ACCESSORIES

PRIMARY

DISCONNECTS

SECONDARY

DISCONNECTS

DRAWOUT

MECHANISMS

SHUNT

TRIPPING

DEVICE

BELL

ALARM

AND

LOCKOUT

DEVICE

OPEN

FUSE

LOCKOUT

DEVICE

42

43

44

45

47

MISCELLANEOUS

TOOLS

RENEWAL

’

PARTS

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

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

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

.

The

proce

-

dure

for

inserting

the

safety

is

given

below

.

INSERTING

SAFETY

AK

-

50

,

-

75

and

-

100

(

Fig

.

3

)

The

closing

spring

should

be

charged

with

the

maintenance

handle

(

1

)

so

that

the

safety

(

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

takes

the

spring

force

.

To

install

the

safety

of

the

manual

stored

-

energy

mechanism

refer

to

the

section

entitled

STORED

-

ENERGY

MANUAL

MECHANISM

on

page

17

of

these

instructions

.

With

the

safety

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

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

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

removed

from

the

push

rod

,

and

the

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

left

in

push

rod

..

Motor

burned

out

.

Adjust

latch

.

Replace

spring

.

Clean

bearing

and

latch

surfaces

.

Remove

safety

.

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

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

(

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

)

,

(

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

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

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

(

19

)

.

This

relative

motion

is

obtained

by

linkages

from

the

upper

(

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

(

18

)

,

which

holds

them

to

the

lower

block

.

Motion

is

obtained

from

a

second

(

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

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

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

(

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

Low

Voltage

Power

Circuit

Breakers

GEK

-

7303

1

.

Screw

2

.

Stationary

Arcing

Contact

3

.

(

Stationary

Arcing

Contact

)

4

.

Movable

Arcing

Contact

5

.

Spring

(

Leaf

Contact

)

5

A

.

Stationary

Intermediate

Contact

6

.

Movable

Main

Contact

7

.

Shouldered

8

.

(

Arcing

Contact

Links

)

9

.

Insulating

Link

10

.

(

Insulating

Link

)

IOA

.

Adjusting

Plate

IOB

.

Buffer

Spacers

11

.

(

Side

Link

)

12

.

Link

13

.

Clevis

14

.

Clevis

15

.

Lower

Stud

16

.

Pole

Unit

Base

17

.

Spring

(

Main

Movable

Contact

)

18

.

(

Main

Movable

Contact

)

19

.

(

Movable

Arcing

Contact

)

20

.

Side

Link

20

A

.

Contact

Stop

21

.

Spring

(

Stationary

Main

Contact

)

22

.

Spring

(

Stationary

Arcing

Contact

)

23

.

Upper

Stud

24

.

Leaf

Spring

(

Stationary

Main

Contacts

)

25

.

(

Stationary

Main

Contact

)

26

.

Stationary

Main

Contact

27

.

Screw

28

.

Stop

28

27

26

25

24

22

21

20

A

20

19

18

17

16

15

12

13

14

Fig

.

6

(

0107

D

7517

)

Pole

unit

assembly

-

AK

-

50

at

least

3

/

16

in

.

,

the

main

contacts

gap

at

least

1

/

4

in

.

spacers

on

the

cross

-

bar

.

The

locking

nuts

on

the

buffer

bolts

should

be

locked

in

such

a

posi

-

tion

that

the

buffer

bolt

may

be

rotated

freely

.

This

check

can

best

be

made

NOTE

:

by

means

of

the

maintenance

handle

,

with

the

safety

restraining

the

closing

springs

.

REPLACEMENT

OF

CONTACTS

(

Fig

.

6

)

Stationary

Arcing

Contacts

(

2

,

Fig

.

6

)

0

,

Fig

.

7

)

1

.

Remove

the

upper

plate

by

removing

two

screws

(

1

)

.

On

the

AK

-

75

and

-

100

remove

the

top

contact

block

(

25

,

Fig

.

7

)

and

remove

insulation

(

3

,

Fig

.

7

)

.

2

.

Loosen

screws

holding

spring

.

(

5

)

3

.

Remove

(

3

)

freeing

the

stationary

con

-

tacts

and

springs

(

22

)

.

4

.

Install

new

springs

and

stationary

arcing

contacts

in

reverse

order

.

If

the

gap

is

under

the

required

minimum

,

it

is

usually

possible

to

form

the

arcing

contacts

and

obtain

the

required

dimensions

.

To

form

the

con

-

tacts

,

place

a

piece

of

conduit

approximately

two

feet

long

,

over

the

contact

and

form

the

contact

either

forward

or

backward

.

If

the

proper

dimen

-

sions

are

still

not

obtained

the

movable

arc

-

ing

contacts

should

be

replaced

.

If

it

has

been

necessary

to

make

any

adjust

-

ments

while

obtaining

proper

contact

sequence

,

the

contact

wipe

and

pressure

must

be

checked

,

and

adjusted

,

if

necessary

.

CONTACT

GAP

(

Fig

.

6

)

When

the

breaker

is

open

,

the

gap

between

the

movable

and

stationary

contacts

should

be

between

2

5

/

8

in

.

and

2

3

/

4

in

.

The

gap

may

be

adjusted

by

varying

the

number

of

buffer

5

.

Adjust

contact

wipe

and

pressure

.

(

See

ADJUSTING

CONTACT

WIPE

AND

PRESSURE

)

.

11

Courtesy of NationalSwitchgear.com

GEK

-

7303

Low

Voltage

Power

Circuit

Breakers

l

STATIONARY

ARCING

CONTACT

2

.

(

STATIONARY

ARCING

CONTACT

)

3

.

INSULATION

4

MOVABLE

ARCING

CONTACT

4

A

.

STAT

INTERMEDIATE

CONTACT

5

.

MOVABLE

MAIN

CONTACT

6

SHOULDERED

7

LINK

a

(

ARCING

CONTACT

LINK

)

9

.

INSULATING

LINK

IQ

(

INSULATING

LINK

)

IOA

.

ADJUSTING

PLATE

11

.

(

SIDE

LINK

)

12

.

CLEVIS

13

.

CLEVIS

14

.

LOWER

STUD

15

.

POLE

UNIT

BASE

16

SPRING

(

MAIN

MOVABLE

CONTACT

)

17

.

(

MOVABLE

MAIN

CONTACT

)

18

(

MOVABLE

ARCING

CONTACT

)

19

.

SIDE

LINK

20

.

SPRING

(

STATIONARY

MAIN

CONTACT

)

21

.

SPRING

(

STATIONARY

ARCING

CONTACT

)

22

.

UPPER

STUD

23

.

(

STATIONARY

MAIN

CONTACT

)

24

.

STATIONARY

MAIN

CONTACT

25

.

TOP

CONTACT

BLOCK

)

~

u

Fig

.

7

(

215

D

174

)

Pole

unit

assembly

-

AK

-

75

and

AK

-

100

The

movable

arcing

contacts

(

4

)

should

be

replaced

when

the

stationary

arcing

contacts

are

replaced

.

scribed

above

.

2

.

Remove

screws

(

27

)

and

remove

bracket

which

holds

(

25

)

in

place

.

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

operating

the

breaker

with

the

maintenance

handle

,

with

the

safety

in

place

,

until

the

load

on

the

contact

stop

is

relieved

.

Separate

the

front

frame

from

the

back

frame

as

described

under

SEPARATION

OF

FRONT

AND

REAR

FRAMES

.

1

.

2

.

Remove

pins

(

8

)

and

(

19

)

and

withdraw

the

contacts

.

3

.

Reassemble

parts

in

reverse

order

.

Stationary

,

Intermediate

and

Main

Contacts

(

Fig

.

6

)

Remove

stationary

arcing

ctonacts

as

de

-

4

o

Loosen

the

hardware

which

fastens

the

upper

stud

to

the

pole

unit

base

until

the

contact

1

.

12

Courtesy of NationalSwitchgear.com

Low

Voltage

Power

Circuit

Breakers

GEK

-

7303

u

X

]

i

—

2

—

L

9

3

-

—

j

4

i

8

5

-

3

^

fVlO

,

6

J

i

.

'

3

Fig

.

8

(

8014678

)

Front

view

of

back

frame

assembly

-

AK

-

2

-

50

6

.

Crossbar

7

.

Series

Overcurrent

Device

8

.

Movable

Inter

-

mediate

Contact

9

.

Stationary

Inter

-

mediate

Contact

1

.

Stationary

Arcing

Contact

2

.

Movable

Arcing

Contact

3

.

Stationary

Main

Contact

4

.

Clamp

5

.

Movable

Main

Contact

Fig

.

9

(

8039669

)

Front

view

of

back

frame

assembly

-

AK

-

3

-

50

1

.

Power

Sensor

Coil

Assembly

2

.

Disconnect

Plug

3

.

Transformer

Taps

in

Amperes

spring

load

on

(

25

)

is

relieved

.

5

.

Remove

(

25

)

and

screws

(

27

)

and

lift

out

contacts

.

ing

contact

replacement

.

(

See

ADJUSTING

CONTACT

WIPE

AND

PRESSURE

)

.

OPERATING

MECHANISMS

ELECTRICALLY

OPERATED

AK

-

50

,

-

75

and

-

100

;

MANUAL

AK

-

50

The

electrically

operated

mechanism

includes

a

motor

and

a

gear

reduction

unit

,

which

charges

the

closing

springs

(

16

,

Fig

.

10

)

through

a

crank

shaft

(

14

,

Fig

.

10

)

.

The

crank

shaft

has

an

arm

with

a

roller

(

12

,

Fig

.

10

)

which

rides

on

the

closing

cam

(

2

,

Fig

.

11

)

.

closing

cam

roller

is

shown

in

Fig

.

11

A

,

11

B

,

and

11

C

.

center

-

pole

unit

through

a

clevis

and

through

a

crossbar

it

controls

the

opening

and

closing

of

the

contacts

on

all

pole

units

.

Charging

the

Closing

Springs

(

Fig

.

10

)

6

o

Reassemble

contacts

in

reverse

order

,

being

careful

to

replace

the

intermediate

contact

in

the

proper

position

.

Movable

Intermediate

and

Main

Contacts

(

Fig

.

6

)

1

.

Remove

the

movable

arcing

contacts

as

described

above

.

The

position

of

this

2

.

Loosen

spring

(

17

)

.

3

.

Remove

braid

if

present

by

removing

screw

at

bottom

of

contact

.

The

closing

cam

is

connected

to

the

4

.

Slide

link

(

12

)

to

the

side

and

off

of

(

7

)

.

The

mechanism

in

position

is

shown

in

1

.

5

.

Slide

pins

(

7

)

and

(

18

)

far

enough

to

the

side

to

allow

the

movable

intermediate

contacts

to

be

replaced

.

Fig

.

11

A

.

2

.

The

motor

turns

the

crank

(

10

)

which

is

mounted

on

the

output

shaft

of

the

gear

reduc

-

tion

unit

.

The

charging

roller

,

which

is

on

the

face

of

the

crank

,

has

paddle

arm

(

11

)

bearing

on

it

.

6

.

Reassemble

parts

in

reverse

order

.

Always

check

contact

wipe

and

pressure

follow

-

13

Courtesy of NationalSwitchgear.com

GEK

-

7303

Low

Voltage

Power

Circuit

Breakers

FIG

-

1

IB

MECHAMSM

IN

RESET

P

03

TICN

MECHANISM

IN

NOTION

BEFORE

RESETTING

AS

SHOWN

IN

FIG

.

-

11

B

15

it

—

15

2

-

3

u

9

1

.

2

.

Bushing

3

.

Bracket

4

.

Indicator

5

.

Bracket

6

.

Frame

7

.

Crank

Roller

8

.

Gear

Reduc

-

tion

Unit

9

.

Motor

10

.

Crank

11

.

Paddle

12

.

Closing

Cam

Roller

13

.

Closing

Cam

Arm

14

.

Crank

Shaft

15

.

Spring

Charg

-

ing

Arm

16

.

Closing

Spring

17

.

Push

Rod

18

.

Clip

FIG

-

11

C

MECHANISM

IN

CLOSED

POSITION

(

CLOSING

SPRING

DISCHARGED

)

1

.

Spring

2

.

Cam

3

.

Link

4

.

Reset

Spring

4

A

.

Spring

Adjusting

Nuts

5

.

Prop

6

.

Adjusting

Screw

7

.

Adjusting

Screw

Stop

8

.

Prop

Return

Spring

9

.

Roller

10

.

Trip

Latch

11

.

T

rip

Shaft

12

.

Clevis

13

.

Clevis

14

.

Latch

Buffer

Stop

(

Bronze

Material

)

15

.

Roller

16

.

Prop

Fig

.

10

(

541

E

304

)

Closing

spring

and

charging

mechanism

3

.

As

the

crank

turns

,

the

roller

pushes

the

paddle

arm

upward

,

thereby

charging

the

closing

springs

through

the

spring

charging

arm

(

15

)

of

the

crank

shaft

.

4

.

As

the

charging

roller

approaches

dead

center

a

cut

-

off

switch

opens

,

de

-

energizing

the

motor

circuit

.

Fig

.

11

(

541

E

305

)

Operating

mechanism

Closing

the

Breaker

Electrically

Operated

(

Fig

.

10

)

1

.

With

the

mechanism

in

the

position

described

above

and

the

closing

springs

charged

,

applying

a

closing

signal

will

cause

the

motor

to

continue

to

charge

the

closing

springs

allowing

the

mech

-

anism

to

reset

,

if

not

already

reset

,

to

the

posi

-

tion

shown

in

Fig

.

11

B

.

5

.

The

breaker

is

now

ready

to

close

when

a

closing

signal

is

given

.

6

.

With

the

breaker

resting

at

the

precharge

position

,

the

trip

latch

may

or

may

not

be

in

the

reset

position

.

This

depends

on

the

position

of

roller

(

15

,

Fig

.

11

B

)

with

respect

to

the

cam

(

2

,

Fig

.

11

B

)

.

14

Courtesy of NationalSwitchgear.com

t

-

m

Fig

.

12

(

8018989

)

Rear

view

of

front

frame

-

AK

-

50

showing

cam

shaft

locking

plate

being

loosened

Fig

.

13

(

8018984

)

Rear

view

of

front

frame

-

AK

-

50

showing

cam

shaft

locking

plate

and

cam

shaft

removed

(

The

mechanism

should

be

reset

by

Fig

.

11

B

.

manual

operation

with

the

safety

in

place

and

with

roller

(

15

)

clear

of

cam

(

2

)

.

2

.

As

the

crank

roller

(

7

)

passes

its

top

dead

-

center

position

,

(

maximum

spring

charge

position

)

the

closing

springs

are

free

to

discharge

.

Crank

(

10

)

can

be

overdriven

independently

of

the

motor

so

that

roller

(

7

)

assumes

its

bottom

dead

-

center

position

without

restraint

.

30

As

the

springs

discharge

,

the

rotation

of

the

crank

shaft

(

14

)

causes

roller

(

15

,

Fig

.

11

)

to

rotate

cam

(

2

,

Fig

.

11

)

and

raise

clevis

(

13

,

Fig

.

11

)

.

Prop

(

16

,

Fig

.

11

)

holds

cam

(

2

,

Fig

.

11

C

)

in

this

position

.

4

.

Raising

clevis

(

13

,

Fig

.

11

C

)

closes

the

breaker

contacts

through

the

pole

base

linkage

.

Tripping

the

Breaker

(

Fig

.

11

)

Operation

of

any

of

the

trip

devices

rotates

the

trip

shaft

(

11

)

which

allows

the

trip

latch

(

10

)

to

release

the

latch

prop

(

5

)

.

This

allows

the

forces

of

the

contact

and

opening

springs

to

reposition

the

operating

mechanism

linkage

to

the

position

shown

in

Fig

.

11

A

.

In

this

position

,

the

operating

cycle

may

be

repeated

.

Adjustments

(

Fig

.

11

)

All

adjustments

should

be

made

with

the

opera

-

ting

mechanism

in

the

reset

position

as

shown

in

1

.

The

gap

between

the

trip

latch

(

10

)

and

the

roller

(

9

)

of

the

reset

latch

should

be

between

1

/

64

in

.

and

1

/

32

in

.

This

adjustment

can

be

obtained

by

turning

screw

(

6

)

.

2

.

The

center

line

of

the

trip

latch

(

10

)

should

pass

through

the

center

of

the

roller

(

9

)

0

The

latch

buffer

stop

on

the

mechanism

frame

can

be

adjusted

by

loosening

the

retaining

screws

to

reposition

the

latch

with

respect

to

the

roller

.

3

.

The

distance

between

the

roller

on

link

(

3

)

and

prop

(

5

)

should

be

between

1

/

64

in

.

and

l

/

32

in

.

To

obtain

this

gap

,

advance

or

retard

the

nuts

(

4

A

)

on

the

bottom

of

the

rod

using

the

reset

spring

(

4

)

.

Replacement

When

replacing

the

operating

mechanism

,

refer

to

the

section

titled

SEPARATION

OF

FRONT

AND

BACK

FRAMES

under

MAINTENANCE

in

these

instructions

.

The

motor

is

mounted

on

the

side

of

the

gear

-

15

Courtesy of NationalSwitchgear.com

GEK

-

7303

Low

Voltage

Power

Circuit

Breakers

reduction

unit

and

through

a

worm

gear

and

a

planetary

gear

train

drives

the

crank

(

10

,

Fig

.

10

)

with

a

reduction

1000

:

1

.

To

remove

the

motor

and

gear

-

reduction

unit

,

proceed

as

follows

:

1

.

Remove

the

front

frame

(

see

SEPARATION

OF

FRONT

AND

REAR

FRAME

.

)

2

.

Remove

closing

springs

and

crank

-

shaft

as

illustrated

in

Fig

.

12

and

13

.

3

.

Disconnect

the

leads

from

motor

and

remove

the

wires

attached

to

gear

unit

housing

.

4

.

Remove

four

bolts

at

the

bottom

of

the

front

frame

and

one

bolt

at

top

of

gear

reduction

unit

.

The

motor

and

gear

unit

may

now

be

removed

.

NOTE

:

If

it

is

desired

to

replace

only

the

motor

unit

,

disconnect

the

motor

leads

and

remove

only

the

hardware

fastening

it

to

the

gear

-

reduction

unit

.

When

removing

the

motor

only

,

the

front

frame

should

be

placed

front

side

down

to

prevent

the

oil

escaping

from

the

gear

unit

.

"

B

'

A

"

O

LATCH

ROLLER

Fig

.

14

A

The

gear

reduction

unit

contains

4

ounces

of

oil

similar

to

Atlantic

Refining

Company

’

s

Grade

HFS

No

.

3

.

'

It

should

not

be

necessary

to

add

or

change

oil

except

when

the

gear

-

reduction

unit

and

motor

are

disassembled

.

Quick

-

Closing

Release

Latch

-

Fig

.

14

A

Adjust

the

engagement

of

the

roller

on

the

latch

to

l

/

8

”

±

l

/

64

”

by

turning

the

screw

"

A

”

.

After

adjustment

is

set

,

lock

the

bolt

with

the

hex

nut

TfBTT

.

Adjust

the

clearance

between

the

latch

and

the

roller

to

1

/

32

+

0

-

1

/

64

by

turning

the

screw

TTCTT

.

QUICK

CLOSE

BREAKER

ADJUSTMENTS

The

quick

close

breaker

basically

differs

from

the

standard

breaker

in

that

the

precharging

operation

is

extended

to

and

slightly

past

the

top

dead

center

position

of

the

closing

spring

assembly

.

As

the

springs

start

to

discharge

to

close

the

breaker

,

the

discharge

operation

is

arrested

by

a

prop

and

latch

arrangement

.

The

subsequent

closing

operation

is

accomplished

by

tripping

the

latch

to

release

the

prop

which

in

turn

allows

the

springs

to

continue

the

interrupted

discharging

operation

and

close

the

breaker

.

The

gear

reduction

unit

for

the

standard

breaker

is

not

interchangeable

with

the

gear

reduction

unit

-

on

the

quick

close

unit

because

the

quick

close

gear

reduction

unit

employs

a

slip

clutch

to

relieve

the

pressure

that

would

otherwise

be

exerted

between

the

output

crank

plate

and

the

prop

.

After

the

closing

springs

have

been

completely

charged

and

the

prop

and

latch

system

are

pre

-

venting

closure

of

the

breaker

,

the

closing

opera

-

tion

may

be

accomplished

by

energizing

the

closing

relay

thru

the

control

relay

contacts

,

or

man

-

ually

by

depressing

the

push

to

close

lever

which

mechanically

displaces

the

latch

to

allow

the

breaker

to

close

.

MAGNET

SPACER

jm

A

ROLLER

RELEASE

ARM

O

ARMATURE

32

^

0

;

GO

[

*

“

I

Fig

.

14

B

Release

Arm

Adjusting

-

Fig

.

14

B

Adjust

release

arm

screw

”

D

”

so

that

the

stroke

of

the

armature

of

the

closing

solenoid

releases

the

roller

from

the

latch

with

a

minimum

of

1

/

32

”

over

-

travel

.

Check

by

using

1

/

32

”

GO

and

3

/

32

”

NO

GO

gauge

between

armature

and

magnet

.

On

drawout

breakers

an

interlock

between

the

breaker

and

enclosure

requires

the

springs

to

be

discharged

before

the

breaker

can

be

removed

from

the

enclosure

.

16

Courtesy of NationalSwitchgear.com

Low

Voltage

Power

Circuit

Breakers

GEK

-

7303

used

on

the

AK

-

50

,

-

75

and

-

100

electrical

breakers

.

The

closing

springs

(

5

)

are

charged

by

operating

the

manual

closing

handle

(

22

)

on

the

front

of

the

breaker

,

instead

of

the

closing

motor

as

is

the

case

with

the

electrical

breaker

.

Closing

this

breaker

is

accomplished

by

pumping

the

operating

handle

four

complete

cycles

,

first

counterclockwise

through

120

degrees

from

its

normal

vertical

position

and

then

clockwise

back

through

120

degrees

from

its

normal

vertical

position

and

then

clockwise

back

through

120

degrees

.

When

approximately

70

degrees

of

the

fourth

clockwise

stroke

have

been

completed

,

the

closing

springs

,

which

have

been

charged

during

the

ot

the

closing

handle

,

are

driven

over

-

center

and

the

breaker

closes

.

t

RELEASE

ARM

o

/

v

ARMATURE

-

3

J

2

Q

°

4

M

0

G

0

/

LEVER

MAGNET

This

mechanism

consists

basically

of

a

closing

spring

assembly

,

ratchet

wheel

and

output

crank

assembly

,

handle

shaft

and

pawl

assembly

,

and

the

closing

handle

.

Fig

.

14

C

Closing

the

Breaker

(

Fig

.

15

)

The

first

stroke

of

the

closing

handle

causes

the

ratchet

pawls

(

21

)

attached

to

the

handle

shaft

(

23

)

,

to

engage

the

first

tooth

of

the

ratchet

wheel

(

17

)

,

thus

beginning

to

charge

the

closing

springs

.

The

subsequent

closing

handle

strokes

perform

the

same

function

as

the

pawls

(

21

)

engage

the

teeth

in

the

ratchet

wheel

(

17

)

,

thus

rotating

the

ratchet

wheel

and

output

crank

(

32

)

and

completely

charging

the

closing

springs

.

This

rotation

of

the

ratchet

wheel

and

output

crank

is

in

a

counterclockwise

direction

from

the

lower

position

,

through

slightly

more

than

180

degrees

,

to

a

position

just

beyond

dead

center

,

In

this

position

the

closing

springs

are

free

to

release

their

energy

,

closing

the

breaker

at

a

high

speed

.

Release

Shaft

Stop

and

Switchette

-

Fig

.

14

C

Adjust

screw

”

E

”

to

1

/

32

”

clearance

between

screw

and

lever

with

clearance

on

release

arm

taken

up

by

pressing

lever

lightly

forward

.

Adjust

switchette

operation

by

adding

washers

”

F

”

under

cotter

,

so

that

contact

is

made

when

armature

is

adjusted

as

shown

above

.

The

control

relay

or

(

X

)

relay

is

located

on

the

left

side

of

the

front

frame

channel

.

It

may

be

removed

by

disconnecting

the

wiring

,

loosening

the

(

3

)

two

mounting

screws

and

lifting

it

slightly

to

admit

the

top

mounting

screw

through

the

keyhole

mounting

,

in

general

,

the

entire

relay

should

be

replaced

rather

than

changing

coils

and

contacts

.

Inserting

the

Safety

(

Fig

.

15

)

If

it

is

desired

to

slowly

close

the

breaker

contacts

to

check

contact

wipe

and

sequence

,

operate

the

closing

handle

3

1

/

2

as

described

above

,

counterclockwise

stroke

and

before

performing

the

fourth

clockwise

stroke

,

insert

the

safety

(

3

)

into

the

hole

(

4

)

in

the

guide

rod

(

6

)

,

thus

preventing

the

closing

springs

(

5

)

from

releasing

their

energy

to

close

the

breaker

contacts

.

Replacement

(

Fig

.

15

)

If

it

is

necessary

to

replace

any

of

the

mech

-

anism

parts

,

the

following

total

procedure

is

recommended

,

at

the

step

required

to

replace

any

particular

part

:

complete

cycles

At

the

end

of

the

fourth

The

anti

-

pump

relay

is

located

on

the

left

side

of

the

front

channel

above

the

control

relay

.

The

connections

to

this

relay

are

soldered

.

Re

-

moval

of

the

relay

is

straight

forward

.

When

re

-

installing

use

extreme

care

to

avoid

shorting

contact

points

of

different

voltage

potential

with

solder

of

flux

.

This

procedure

may

be

halted

The

closing

control

relay

consists

of

a

strong

box

solenoid

with

sufficient

linkages

to

operate

the

remotely

located

D

switches

.

1

.

Install

the

safety

(

3

)

as

described

.

above

.

Stored

-

Energy

Manual

Mechanism

(

Fig

.

15

)

2

.

AK

-

50

-

75

-

100

Separate

the

front

and

rear

frames

as

described

under

REPARATION

OF

FRONT

AND

REAR

FRAMES

”

in

the

”

MAINTENANCE

”

section

of

these

instructions

.

This

breaker

is

equipped

with

a

spring

-

charged

stored

-

energy

mechanism

similar

to

the

mechanism

17

Courtesy of NationalSwitchgear.com

GEK

-

7303

Low

Voltage

Power

Circuit

Breakers

\

:

j

-

r

-

£

13

2

3

-

•

/

!

;

4

Z

.

J

i

5

•

—

Zlri

—

ii

i

1

ffi

i

:

6

i

7

!

I

'

I

1

'

:

i

;

l

8

!

I

:

.

-

.

J

r

10

I

12

i

'

13

i

32

14

15

I

16

i

17

i

18

I

19

'

31

t

'

20

21

22

f

*

3

r

23

\

24

25

\

as

26

27

r

E

)

I

28

30

29

©

(

•

l

!

i

/

i

•

i

\

i

:

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i

\

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K

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i

View

FweoKi

~

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WITH

HANDLE

A

.

ME

>

e

^

cuTCHECy

-

i

RE

^

O

’

/

EP

Fig

.

15

(

669

D

805

)

Stored

-

energy

manual

closing

mechanism

charged

position

AK

-

2

1

.

Upper

Spring

2

.

Safety

Holder

3

.

Safety

and

Chain

4

.

Safety

Hole

5

.

Closing

Springs

6

.

Guide

Rod

7

.

Pawl

Springs

8

.

Front

Escutcheon

9

.

Front

Bearing

Plate

10

.

Bearing

Plate

Mounting

Bolts

31

.

Lower

Spring

11

.

Output

Crank

Roller

12

.

Thrust

Bearing

13

.

Shims

14

.

Groove

15

.

Nylok

Screw

16

.

Ratchet

Wheel

Shaft

and

Asm

.

17

.

Ratchet

Wheel

18

.

Side

Plate

Shims

19

.

Side

Plate

Mounting

Bolts

20

.

Bearing

Side

Plate

21

.

Ratchet

Pawls

22

.

Manual

Closing

Handle

23

.

Closing

Handle

Shaft

and

Pawl

Asm

.

24

.

Roll

25

.

Main

Closing

Crank

26

.

Pawl

Buffer

Stop

27

.

Buffer

Stop

Shims

28

.

Buffer

Stop

Support

29

.

Handle

Return

Spring

30

.

Mechanism

Roller

*

32

.

Output

Crank

18

Courtesy of NationalSwitchgear.com

Low

Voltage

Power

Circuit

Breakers

GEK

-

7303

3

.

Remove

the

closing

spring

assembly

by

removing

the

upper

and

lower

spring

pins

(

1

,

31

)

.

4

.

Remove

the

right

hand

bearing

side

plate

(

20

)

,

and

the

side

plate

shims

(

18

)

if

present

,

by

removing

four

mounting

bolts

(

19

)

,

thus

allowing

the

main

closing

crank

(

25

)

to

be

removed

.

5

.

Remove

the

closing

handle

(

22

)

by

removing

two

set

screws

threaded

in

same

hole

.

imum

distance

from

the

center

of

rotation

of

the

ratchet

wheel

(

17

)

.

This

measurement

should

be

made

while

operating

the

closing

handle

during

the

four

spring

charging

operations

and

before

the

closing

springs

are

reassembled

.

3

.

The

ratchet

pawls

(

21

)

should

operate

They

freely

throughout

the

closing

strokes

,

should

engage

the

ratchet

wheel

teeth

near

the

end

of

each

counterclockwise

and

clockwise

stroke

of

the

closing

handle

with

a

definite

clicking

sound

,

indicating

a

free

non

-

binding

operation

,

the

clicking

sound

is

detected

,

the

closing

handle

should

have

a

minimum

overtravel

of

1

/

2

in

.

or

3

1

/

2

degrees

,

measured

at

the

end

of

each

handle

stroke

.

6

.

Remove

the

front

escutcheon

by

removing

four

screws

holding

it

to

the

front

frame

center

support

.

7

.

Remove

the

handle

return

spring

(

29

)

by

unhooking

either

end

of

the

spring

.

8

.

Disconnect

the

top

end

of

each

pawl

spring

After

4

.

The

groove

(

14

)

in

the

front

of

the

ratchet

wheel

assembly

(

16

)

must

be

assembled

in

a

manner

that

will

allow

Nylok

screw

(

15

)

to

be

tightened

securely

.

A

clearance

of

1

/

64

to

1

/

32

in

.

should

exist

between

the

front

of

the

groove

and

the

rear

surface

of

the

Nylok

screw

head

.

Other

adjustments

to

the

closing

and

operating

mechanisms

,

such

as

complete

contact

and

latch

adjustments

,

may

be

made

by

following

the

pre

-

viously

described

instructions

for

the

AK

-

50

,

-

75

and

-

100

breaker

mechanisms

.

(

7

)

.

(

24

)

,

thus

allowing

(

23

)

and

pawl

assembly

9

.

Remove

the

roll

the

closing

handle

shaft

(

23

)

to

be

removed

.

10

.

Remove

the

ratchet

wheel

(

17

)

and

its

assembly

(

16

)

by

removing

Nylok

*

screw

(

15

)

and

thrust

bearing

(

12

)

.

If

shims

(

13

)

are

present

they

must

also

be

removed

.

11

.

Remove

front

bearing

plate

(

9

)

by

removing

three

mounting

bolts

(

10

)

accessible

from

the

front

of

the

breaker

.

The

mechanism

is

now

completely

disassembled

,

of

the

subassemblies

removed

during

the

above

operation

be

further

disassembled

in

the

field

.

Replacement

sub

-

assemblies

should

be

obtained

from

the

factory

.

12

.

To

reassemble

the

mechanism

,

reverse

the

procedure

described

above

.

NOTE

:

When

reassembling

the

mechanism

the

adjustments

listed

below

should

be

checked

at

the

appropriate

time

of

reassembly

,

appropriate

time

for

each

adjustment

is

in

-

dicated

in

the

adjustment

text

.

Adjustments

(

Fig

.

15

)

It

is

not

recommended

that

any

i

)

FIELD

SWITCH

FIELD

DISCHARGE

CONTACTS

DISCHARGE

RESISTOR

r

\

The

FIELD

WINDING

wvwvw

Frequent

adjustments

to

the

mechanism

should

If

the

mechanism

has

been

not

be

required

,

disassembled

,

it

will

be

necessary

to

check

the

following

adjustments

:

Fig

.

16

(

415

A

845

)

Typical

connection

diagram

AKF

MECHANISM

(

Fig

.

17

)

The

Type

AKF

breakers

are

two

-

pole

breakers

with

field

discharge

contacts

placed

in

the

center

pole

.

When

this

breaker

is

opened

,

the

field

discharge

contacts

close

,

thus

connecting

an

ex

-

ternal

discharge

resistor

across

the

field

of

the

generator

or

motor

.

When

the

breaker

is

closed

,

the

field

discharge

contacts

are

opened

.

See

Fig

.

16

for

a

typical

circuit

connection

.

1

.

It

may

be

necessary

to

add

shims

(

13

)

to

reduce

the

end

play

of

the

ratchet

wheel

shaft

(

16

)

.

An

end

play

of

0.010

to

0.020

of

an

inch

is

recommended

.

Shims

should

be

obtained

from

the

factory

.

2

.

It

may

be

necessary

to

add

buffer

stop

shims

(

27

)

to

the

buffer

stop

(

26

)

to

provide

a

clearance

of

1

/

64

to

1

/

32

inch

between

the

pawls

(

21

)

and

the

buffer

stop

,

when

the

pawls

are

touching

the

ratchet

wheel

teeth

extending

a

max

-

*

Trade

-

mark

of

Republic

Steel

Corp

.

19

Courtesy of NationalSwitchgear.com

GEK

-

7303

Low

Voltage

Power

Circuit

Breakers

T

1

.

Springs

2

.

Insulation

3

.

Stationary

Contact

4

.

5

.

Screw

6

.

Movable

Contact

7

.

8

.

Buffer

9

.

Crossbar

10

.

Adjusting

Plate

11

.

Bolt

12

.

Buffer

13

.

Screw

14

.

Shims

15

.

Bolt

16

.

17

.

17

—

16

15

Fig

.

17

(

227

D

174

)

Field

discharge

contacts

(

center

pole

)

and

pressure

may

be

made

by

following

the

same

procedure

as

outlined

for

the

standard

pole

unit

in

POLE

UNIT

ASSEMBLY

.

Overlap

of

the

center

-

pole

contacts

and

the

outer

pole

arcing

contacts

may

be

checked

by

the

following

procedure

:

Remove

arc

quenchers

(

see

ARC

QUEN

-

t

When

the

breaker

is

tripped

,

the

opening

springs

pull

crossbar

(

9

)

downward

,

opening

the

breaker

'

s

outer

poles

.

As

the

crossbar

moves

downward

,

link

(

A

)

rotates

about

a

fixed

center

(

17

)

,

collapsing

toggle

links

(

B

)

and

(

C

)

upward

,

therby

closing

center

-

pole

contacts

through

connecting

link

(

D

)

.

Link

(

C

)

consists

of

two

links

riveted

together

,

forming

a

single

triangular

link

.

1

.

CHER

)

.

2

.

Insert

safety

in

push

rod

.

(

See

Fig

.

3

under

MAINTENANCE

.

)

Contact

Adjustments

Measurements

3

.

Operate

closing

mechanism

with

mainten

-

ance

handle

until

arcing

contacts

of

outer

poles

just

touch

.

4

.

Measure

distance

between

forward

edge

of

left

stationary

contact

of

center

pole

and

surface

of

insulation

block

behind

contact

.

For

contact

measurements

and

adjustments

of

the

two

outside

poles

of

the

breaker

,

refer

to

POLE

UNIT

ASSEMBLY

.

Contact

measurements

of

the

center

-

pole

field

discharge

contacts

should

be

made

on

the

left

contact

and

be

within

the

following

limits

:

1

.

Contact

wipe

,

3

/

16

in

.

to

7

/

16

in

.

2

.

Contact

pressure

,

10

lb

.

to

16

lb

.

3

.

Gap

between

contacts

when

center

pole

is

open

,

1

/

2

in

.

to

1

3

/

4

in

.

4

.

Overlap

between

the

center

-

pole

contacts

and

the

arcing

contacts

of

the

outer

poles

,

3

/

16

in

.

to

7

/

16

in

.

Measurements

of

the

center

-

pole

contact

wipe

5

.

Continue

to

operate

maintenance

closing

handle

until

center

-

pole

contact

opens

fully

.

6

.

Repeat

measurement

described

in

step

4

.

Difference

between

measurements

indicates

amount

of

overlap

.

Adjusting

Center

-

pole

Contact

Wipe

and

Overlap

(

Fig

.

17

)

If

measurements

reveal

either

incorrect

center

-

pole

contact

wipe

or

incorrect

overlap

of

contacts

,

adjustments

should

be

made

by

the

following

procedure

:

j

20

Courtesy of NationalSwitchgear.com

GE AK-50 Series Technical specifications

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