Westinghouse DB-50 User manual

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Type
DB
-
50
"
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Air
Circuit
Breaker
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Frame
Size
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A
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Interrupting
Rating
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WESTIN
6
HOUSE
ELECTRIC
CORPORATION
Switchgear
Apparatus
Departments
,
East
Pittsburgh
,
Pa
.
I
.
B
.
33
-
850
-
3
Supersedes
I
.
B
.
35
-
230
-
C
3
July
,
1959
Printed
In
U
.
S
.
A
.
Courtesy of NationalSwitchgear.com

<
TABLE
OF
CONTENTS
Page
Description
Port
I
—
Receiving
,
Handling
,
and
Storing
6
Inspection
.
Storing
.
.
6
Part
II
—
Installation
7
Connections
Part
III
—
Maintenance
10
Pole
Unit
Contacts
Maintenance
of
Contacts
Operating
Mechanism
Closing
Spring
Mechanism
*
Closing
Solenoid
Overcurxent
Tripping
Device
Installation
and
Removal
Construction
Time
-
Current
Classification
Operation
Time
Current
Characteristics
Adjustment
of
Calibration
Settings
Maintenance
Control
Relay
-
Shunt
Trip
Attachment
Undervoltage
Trip
Attachment
.
Undervoltage
Time
Delay
Attachment
Reverse
Current
Trip
Attachment
.
.
.
Field
Discharge
Switch
.
.
..
Auxiliary
Switch
Alarm
Switch
Attachment
Electric
Lockout
Attachment
Key
Lock
Attachment
Key
Interlock
Attachment
Rectifier
Unit
for
A
-
c
Undervoltage
and
A
-
c
Electric
Lockout
Attachments
10
10
10
i
10
10
11
13
15
15
17
17
19
21
21
22
23
24
24
24
24
28
28
28
28
29
i
2
Courtesy of NationalSwitchgear.com

:
I
LIST
OF
ILLUSTRATIONS
i
Poge
Figure
8
DB
-
50
Outline
Dimensions
and
Mounting
Details
Typical
Wiring
Diagrams
-
Type
DB
-
50
Circuit
Breaker
Cross
-
Sectional
View
of
Type
DB
-
50
Circuit
Breaker
Type
DB
-
50
Spring
Closing
Mechanism
Series
Overcurrent
Tripping
Device
with
Long
Delay
and
Instantaneous
Elements
Series
Overcurrent
Tripping
Device
Showing
the
Assembly
of
Calibration
Case
to
Magnetic
Circuit
Cross
-
Sectional
View
of
Series
Overcurrent
Tripping
Device
with
Long
Delay
and
Instantaneous
Elements
Tripping
Characteristics
of
Standard
Series
Overcurrent
Tripping
Device
with
Long
Delay
and
Instantaneous
Elements
.
Tripping
Characteristics
of
Selective
Series
Overcurrent
Tripping
Device
with
Long
Delay
and
Short
Delay
Elements
Tripping
Characteristics
of
Special
Series
Overcurrent
Tripping
Device
with
Instantaneous
Element
Only
Schematic
Diagram
of
Standard
Series
Overcurrent
Tripping
Device
with
Adjustable
Long
Delay
and
Adjustable
Instantaneous
Elements
.
.
,
Schematic
Diagram
of
Selective
Series
Overcurrent
Tripping
Device
with
Adjustable
Long
Delay
and
Adjustable
Short
Delay
Elements
Schematic
Diagram
of
Special
Series
Overcurrent
Tripping
Device
with
Instantaneous
Element
Only
Instantaneous
Pick
-
Up
Per
cent
of
Coil
Rating
vs
Scale
Settings
Obtained
by
means
of
Standard
Instantaneous
Adjusting
Knob
Closing
Solenoid
-
Construction
Details
Control
Relay
-
Adjustment
and
Construction
Details
Shunt
Trip
Attachment
-
Construction
Details
Undervoltage
Trip
Attachment
-
Construction
Details
Undervoltage
Time
Delay
Attachment
-
Construction
Details
Reverse
Current
Trip
Attachment
-
Construction
Details
Field
Discharge
Switch
-
Construction
Details
Auxiliary
Switch
-
Construction
Details
Alarm
Switch
Attachment
-
Construction
Details
Construction
Details
1
9
2
11
3
12
3
A
4
13
5
13
6
14
7
14
8
15
9
15
10
16
11
18
12
18
13
19
14
20
15
22
16
23
17
25
18
26
26
19
20
27
21
27
22
29
23
Electric
Lockout
Attachment
Key
Lock
or
Key
Interlock
Attachment
-
Construction
Details
Rectifier
Unit
for
A
-
c
Undervoltage
and
A
-
c
Electric
Lockout
Attachments
.
.
30
31
24
32
25
3
Courtesy of NationalSwitchgear.com

<
I
(
£
STS
•
I
•
<
4
Courtesy of NationalSwitchgear.com

”
DB
”
AIR
CIRCUIT
BREAKER
WESTINGHOUSE
Type
"
DB
”
Air
Circuit
Breaker
Type
"
DB
”
air
circuit
breaker is
designed
to
give
continuous and reliable
service
as
the
protective
link
between the
power
source
and associated
productive
equipment
.
This breaker
is
built
to
operate
with
a
minimum
of
maintenance
,
while
at
the
same
time
its
simplified
construction
permits
maximum
accessibility
for
inspection
and
adjustment
when
required
.
The
ease
with which
attachments
may
be added
or
removed
is
an
outstanding
feature of
the
,
TDB
,
T
design
.
For
the
greatest
measure
of
safety
to
operating
personnel
and also
to
minimize
maintenance
requirements
,
the breaker should be mounted
in
an
enclosure suitable
to
local
operating
conditions
.
A
selection
of
standard enclosures
is
available
for
various
applications
.
Important
:
To
assure
proper
functioning
,
inspect
each breaker
at
regular
intervals
in
accordance
with
a
systematic
maintenance
schedule
.
The
frequency
and character
of
the
inspections
will
for
the
most
part
be
determined
by
the
severity
of
the
duty
performed
.
The minimum
requirements
,
however
,
should
consist
of
a
light monthly
inspection
,
with
a
thorough
inspection
semi
-
annually
.
Occasional
checks
on
calibration
as
well
as on
coordination and freedom
of
all
moving
parts
,
must
be
included
in
the maintenance
schedule
.
Consult
Westinghouse
engineering
and
service
personnel
for
recommendations
pertaining
to
special
operating
or
maintenance
conditions
.
5
Courtesy of NationalSwitchgear.com

RECEIVING
,
HANDLING
,
AND
STORING
<
PART
I
—
RECEIVING
,
HANDLING
,
AND
STORING
Type
"
DB
-
50
"
air
circuit
breakers
,
with
all
attachments
mounted
in
place
,
are
shipped
in
wooden
crates
.
a
.
Observe
whether
all
parts
are
in
proper
alignment
and
move
freely
.
Make
certain
that
the
studs
have
not
been
forced
out
of
alignment
.
b
.
Important
:
To
avoid
damage
to
the
breakers
,
do
not
use
hooks
in
handling
.
c
.
Be
sure
that
the
contacts
are
clean
and
properly
aligned
.
For
a
description
of
contact
alignment
,
refer
to
"
Contacts
”
,
Page
10
.
Net
weights
of
Type
DB
-
50
are
given
in
Table
No
.
1
below
.
3
.
If
the
contacts
are
in
alignment
and
all
parts
move
freely
,
continue
the
clockwise
ro
-
tation
until
the
breaker
is
latched
.
TABLE
NO
.
1
NET
WEIGHTS
TYPE
DB
-
50
4
.
Return
the
manual
operating
handle
to
the
neutral
position
,
then
rotate
counterclockwise
to
trip
the
breaker
.
3
-
Pole
280
lbs
.
3
S
5
lbs
.
2
-
Pole
220
lbs
.
298
lbs
.
MANUAL
ELECTRIC
a
.
The
toggle
linkage
should
collapse
and
the
moving
contact
assembly
move
freely
to
the
full
open
position
.
This
should
be
followed
immediately
by
complete
resetting
of
the
links
in
the
toggle
mechanism
as
the
handle
is
re
-
turned
to
the
neutral
position
.
Immediately
upon
receipt
,
examine
shipment
for
any
loss
or
damage
incurred
during
transit
.
If
injury
or
rough
handling
is
evident
,
file
a
damage
claim
at
once
with
the
transportation
company
and
notify
the
nearest
Westinghouse
Sales
Office
.
b
.
The
links
must
always
be
free
to
move
without
friction
or
binding
.
When
unpacking
,
be
sure
that
no
loose
parts
are
missing
or
left
in
the
packing
material
.
Report
all
shortages
at
once
.
Blow
out
any
dust
or
particles
of
packing
material
that
may
have
accumulated
on
the
circuit
breaker
parts
.
I
5
.
Check
the
attachments
for
operation
in
accordance
with
the
appropriate
instructions
as
given
under
r
'
Maintenance
"
,
Part
Three
of
this
book
.
NOTE
:
It
is
not
advisable
to
lubricate
any
parts
of
the
breaker
.
The
lubrication
supplied
during
factory
assembly
is
sufficient
for
years
of
service
.
The
lubricant
is
of
a
special
form
which
is
used
sparingly
.
The
addition
of
oil
will
only
promote
the
accumulation
of
dust
and
dirt
.
INSPECTION
The
"
DB
"
breaker
assembly
consists
of
a
coordinated
group
of
sub
-
assemblies
mounted
on
a
steel
supporting
panel
.
The
complete
breaker
assembly
is
to
be
mounted
with
the
steel
panel
in
a
vertical
position
.
All
inspec
-
tions
for
proper
operation
should
,
therefore
,
be
made
with
the
breaker
in
this
position
.
Final
inspection
should
preferably
be
made
with
the
breaker
in
its
permanent
mounting
.
STORING
If
circuit
breakers
are
not
to
be
installed
in
their
permanent
location
at
once
,
they
should
be
carefully
inspected
for
loose
or
damaged
parts
and
then
stored
in
a
clean
dry
place
in
an
upright
position
to
avoid
damage
to
the
cir
-
cuit
breaker
parts
.
A
covering
of
paper
will
prevent
dust
from
settling
on
the
circuit
breaker
parts
and
is
preferred
to
packing
or
other
ma
-
terials
that
are
apt
to
absorb
moisture
.
Inspect
the
breaker
as
follows
:
1
.
Raise
and
lower
the
trip
bar
by
hand
to
make
sure
that
it
does
not
bind
.
2
.
Rotate
the
manual
operating
handle
slowly
in
a
clockwise
direction
to
move
the
contacts
toward
the
closed
position
.
I
6
Courtesy of NationalSwitchgear.com

"
DB
”
AIR
CIRCUIT
BREAKER
PART
II
—
INSTALLATION
Type
"
DB
-
50
"
circuit
breakers
are
furnished
as
complete
unit
assemblies
and
the
installation
consists
of
:
(
1
)
bolting
them
to
the
supporting
framework
or
structure
;
(
2
)
connecting
the
current
-
carrying
cables
or
bus
bars
;
and
(
3
)
completing
any
secondary
control
wiring
that
may
be
necessary
.
CAUTION
:
During
installation
,
the
circuit
breaker
should
be
in
the
open
position
.
Be
sure
to
de
-
energize
the
load
and
control
leads
to
be
connected
,
and
also
the
section
of
the
switchboard
where
installation
is
being
made
.
CONNECTIONS
Typical
circuit
breaker
wiring
diagrams
are
shown
in
Fig
.
2
.
The
connecting
cables
or
bus
bars
should
have
adequate
current
-
carrying
capacity
,
otherwise
,
heat
will
be
conducted
to
the
circuit
breaker
resulting
in
possible
exces
-
sive
temperature
rise
.
Connecting
cables
or
bus
bars
must
be
supported
so
that
the
circuit
breaker
studs
will
not
be
subjected
to
unneces
-
sary
stresses
.
Mounting
dimensions
and
details
of
the
front
enclosure
cutouts
are
shown
in
Fig
.
1
.
To
prevent
distortion
of
the
breaker
panel
,
the
supporting
structure
should
be
checked
for
alignment
.
The
circuit
breaker
studs
and
all
connections
should
be
clean
,
smooth
,
and
free
from
burrs
to
assure
full
contact
area
.
They
should
be
firmly
clamped
or
bolted
in
place
to
prevent
excessive
heating
.
TABLE
NO
.
2
CLOSING
SOLENOID
CONTROL
VOLTAGES
AND
CLOSING
CURRENTS
CURRENT
IN
AMPERES
AT
NORMAL
VOLTAGE
FOR
OB
-
50
BREAKER
MINIMUM
VOLTAGE
AT
COIL
TERMINALS
NOMINAL
VOLTAGE
Close
Trip
Close
Close
Trip
S
H
24
V
.
D
-
C
48
V
.
D
-
C
125
V
.
D
-
C
250
V
.
D
-
C
II
5
V
.
60
Cy
230
V
.
60
Cy
460
V
.
60
Cy
*
Selenium
Rectox
is
provided
.
S
=
Standard
-
burden
closing
coil
.
H
=
High
-
burden
closing
coil
.
MUST
be
specified
for
each
DB
-
50
breaker
having
short
time
delay
devices
and
for
each
A
-
C
op
-
erated
DB
-
50
breaker
where
closing
power
is
taken
from
the
l
ine
side
of
breaker
and
the
regulation
is
questionable
.
9.5
14
«
•
28
4.9
••
•
2.2
124
90
70
35
62
18
1.1
180
140
3.4
95
124
*
35
*
190
1.7
190
18
*
62
*
380
380
.
7
7
Courtesy of NationalSwitchgear.com

INSTALLATION
<
Approximate
Only
.
Do
Not
Use
for
Construction
Purposes
.
E
3
E
3
£
9
B
9
-
E
3
4
*
E
3
E
3
-
—
E
3
'
THE
FOLLOWING
ATTACHMENTS
CAN
IE
SUPPLIED
WITHOUT
IN
-
CREASING
OVERALL DIMENSIONS
:
Switches
{
12
-
Cir
-
lTlmnrn
)
Current
stud
arrange
-
ment
—
2
-
pole
breaker
with
Held
aisobarge
con
-
tacts
Current
stud
arrange
-
ment
—
2
-
pole
breaker
Current
stud
arrange
-
ment
—
2
-
pole
breaker
witk
reverse
current
at
-
tachment
{
Standard
NEMA
arrangement
)
Auxiliary
cult
Mi
Dio
.
opening
for
f
key
lock
or
key
Interlock
when
required
.
•
Shunt
Trip
•
Under
voltage
Trip
(
With
Without
Time
Delay
)
5
±
5
or
8
•
Alarm
Switch
•
Key
Lock
or
Key
Interlock
•
Field
Discharge
Contact
•
Electric Lockout
•
Operation
Counter
7
\
'
TV
/
£
2
E
2
—
E
3
—
E
3
^
2
3
l
'
/
A
4
±
R
.
*
4
+
tof
Hondle
!
3
|
E
2
—
E
&
E
3
—
E
3
—
E
53
-
Center
Line
of
Breoker
Current
stud
arrange
-
ment
—
2
-
pole
breaker
with
reverse
current
at
-
taohment
(
Standard
ABS
-
A
1
EE
Marine
rangement
)
Current
stud
arrange
-
ment
—
3
-
pole
breaker
Cut
-
out
in
dead
front
door
of
cover
ar
-
Llve
parts
or
combustible
material
must not
be located
In
this
area
,
unless
gas
deflecting
barriers
are
provided
here
.
<
21
51
«
>
ia
.
l
2
)
18
9
Provision
for
padlocking
breoker hondle
in
tripped
position
.
Padlocks
furnished
by
customer
.
4
*
|
7
i
—
8
j
|
Dia
.
t
6
)
Mounting
Holes
3
t
4
6
|
6
6
/
>
|
2
Agpro
»
.
_ _
^
|
£
g
|
Dia
.
(
2
)
%
r
"
"
*
"
7
i
io
32
i
3
4
I
I
±
Is
XJ
2
I
1
n
ij
at
©
4
Cutout
in
Customer
'
s
Mounting
Ponet
4
PL
Arc
13
|
Chute
t
]
l
9
I
I
-
!
*
i
il
li
5
E
Position
—
Indicator
T
8
li
^
3
’
03
1
o
LJ
li
I
.
q
Center
Line
8
i
tl
A
of
Hondle
27
8
q
i
10
s
8
i
P
!
4
Face
Plate
4
B
«
!
To
Trlp
I
=
i
;
To
Close
*
I
4
i
T
*
«
1
2
»
fs
Overcurrent
Trip
Reverse
—
Current
Trip
t
i
Solenoid
L
°
_
L
.
Steel
Base
Mounting
Line
5
a
-
9
l
Center
Pole
Studs
(
Side
View
)
For
field
discharge
contacts
*
4
|
5
U
Min
.
19
i
2
16
Boundary
surfaces of
the
circuit
breoker
are
to
be
considered
ground
potential
Door
or
front
cover
supplied
by
switchboard
builder
.
Fig
.
1
—
DB
-
50
Outline
Dimensions
and
Mounting
8
Courtesy of NationalSwitchgear.com

FIG
.
1
fljTr
T
CONNECTION
DIAGRAM
(
EV
.
)
]
%
;
COFN
^
BUC
FIG
.
10
FIXED
PANEL
SHUNT
TRIP
.
|
.
„
rr
'
r
m
TP
3
*
0
»
A
-
ALARM
CONTACT
DOES
NOT
CLOSE
WHEN
BREAKER
1
S
TRIPPED
MANUALLY
OR
BY
THE
SHUNT
TRIP
t
\
W
;
)
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I
3
i
I
(
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SF
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TN
—
y
—
J
^
5
*
-
CURRENT
LIMITING
RESISTORS
S
FUSES
TO
BE
USED
ONLY
WHEN
CONTROL
SOURCE
15
FROM
SWGR
.
BUS
.
AUX
i
TSi
-
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sw
§
fLO
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SCHEMATIC
CONNECTION
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11
RKyERSE
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—
;
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\
POTENTIAL
COIL
.
3
»
p
COIL
WTEMTIAI
I
COIL
.
I
OPERATION
SEQUENCE
1 .
CONTROL
SWITCH
C
.
S
.
-
C
CLOSED
.
2
.
*
X
*
RELAY
PICKS
UP
5
SEALS
IN
THRU
AUX
.
CONTACTX
*
3
|
400
aRE
5
.
3
.
CLOSING
COIL
ENERGIZED
THRU
^
“
CONTACT
CLOSING
BREAKER
.
4
-
.
IN
CLOSING
BKR
.
CLOSING
MECH
-
M
ECH
AN
ICALLY
TRIPS
"
X
”
CONTACTS
FREE
OF
'
X
‘
COIL
,
INTERRUPTING
CLOSING
CIRCUITS
.
5
.
WITH BKR
.
IN
CLOSED
POSITION
,
THE
BKR
.
CLOSING
MECH
.
IS
LATCHED
UP
AND
"
X
"
CONTACTS
REMAIN
TRIP
FREE
FROM
'
XTQIl
6
.
WHEN
BKR
.
I
5
TRIPPED
CLOSING
MECH
.
DROPS
PERMITTING
'
X
"
CONTACTS
TO
RESET
PROVIDED
'
*
'
COIL
IS
DE
-
ENERGIZED
.
s
-
twins
SCHEMATIC
eaSA
L
_
ifiJ
4
—
4
SCHEMATIC
.
at
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FIG
.
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.
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CONTROL
RELAY
.
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-
CLOSING
COIL
.
TC
-
TRIP
COIL
.
C
5
-
CONTROL
SWITCH
.
,
7
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)
r
^
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8
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^
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#
-
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CS
.
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%
8
cm
CTO
SCHEMATIC
uw
CONNECTION
DIAGRAM
o
CO
T
R
-
1
>
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Fb
U
.
VrUNDERVOLTAGE
.
L
.
O
.
-
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.
A
.
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.
-
ALARM
SWITCH
a
-
WAKE
CONTACT
*
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-
BREAK
CONT
.
-
LZZ
}
JC
FIG
.
12
ALARM
.
A
-
FOR
~
|
A
-
5
.
OPER
.
SEE
I
NOTE
A
|
PAGE
1
.
ELEC
.
PESET
ALARM
SW
.
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|
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|
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>
>
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-
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»
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—
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I
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l
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bf
=
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TN
.
_
‘
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s
ATI
C
.
I
PAGE
1
AS
.
Hqp
1
1
CONTROL
VOLTAGES
I
25
-
250
V
-
D
.
C
.
|
3
j
-
A
~
28
G
1
.
CONNECTION
DIAGRAM
.
^
F
-
V
.
7
m
5
*
5
m
co
Fig
.
2
—
Typical
Wiring
Diagrams
—
Type
DB
-
50
Circuit
Breaker
Courtesy of NationalSwitchgear.com

MAINTENANCE
<
PART
III
—
MAINTENANCE
CLOSING
SPRING
MECHANISM
POLE
UNIT
Each
pole
unit
is
mounted
on
a
separate
molded
base
through
which
the
breaker
studs
pass
.
(
See
Fig
.
3
.
)
The
molded
bases
are
attached
to
the
steel
mounting
panel
and
provide
insulation
for
the
breaker
studs
.
The
closing
spring
mechanism
is
shown
in
Fig
.
3
A
.
Rotating
the
closing
handle
clockwise
raises
the
lift
link
and
lower
spring
guide
to
compress
the
closing
spring
.
Near
the
end
of
the
closing
stroke
the
top
end
of
the
lift
link
strikes
the
first
toggle
lever
to
start
the
breaker
closing
.
As
the
breaker
closes
the
push
rod
raises
the
toggle
link
and
push
link
out
of
the
toggle
which
permits
the
closing
spring
to
complete
the
breaker
closing
.
The
upper
stud
and
contact
are
attached
to
the
molded
base
by
two
bolts
.
The
moving
contact
is
pivoted
on
the
molded
base
and
at
-
tached
to
the
cross
bar
through
insulating
links
.
The
series
coil
and
lower
stud
are
fastened
to
the
molded
base
by
four
bolts
.
CONTACTS
.
(
See
Fig
.
3
.
)
The
DB
-
50
arc
-
ing
contact
should
touch
first
on
closing
,
open
last
on
opening
.
Contact
pressure
on
the
mains
is
maintained
by
adjusting
gap
G
to
be
.
984
-
1.000
inch
.
This
gap
is
adjusted
by
removing
the
cross
bar
and
screwing
the
insulating
link
in
or
out
on
the
stud
.
Be
sure
to
tighten
the
lock
nuts
after
each
adjustment
.
Slow
emergency
operation
to
check
the
con
-
tact
sequence
can
be
obtained
by
exerting
a
slight
closing
pressure
on
the
closing
handle
and
simultaneously
pushing
forward
on
the
breaker
cross
bar
to
start
the
breaker
closing
.
MAINTENANCE
:
Oil
the
pins
and
slides
every
10
,
000
operations
.
CLOSING
SOLENOID
Do
not
over
-
adjust
as
this
will
cause
the
con
-
tact
springs
to
compress
to
the
solid
position
and
thus
increase
the
closing
effort
.
Check
for
over
-
adjustment
by
prying
the
stationary
arc
tips
open
to
at
least
1
/
16
-
inch
gap
.
MAINTENANCE
OF
CONTACTS
.
Rough
or
high
spots
should
be
removed
with
a
file
or
sandpaper
.
To
replace
the
arcing
contacts
,
open
the
breaker
,
remove
the
arc
chutes
and
then
the
stationary
arcing
contacts
.
Close
the
breaker
and
remove
the
moving
arcing
contacts
.
The
new
contacts
can
then
be
added
in
the
reverse
order
.
The
closing
solenoid
(
see
Fig
.
14
)
is
non
-
adjustable
.
It
is
designed
for
intermittent
duty
only
.
Check
for
loose
bolts
.
To
remove
closing
coil
,
trip
breaker
.
Dis
-
connect
closing
coil
leads
from
control
circuit
wiring
.
Take
off
bolts
(
18
)
,
washers
(
19
)
,
relay
release
arm
(
17
)
,
bolts
(
10
)
,
washers
(
11
)
and
plate
(
2
)
.
Drop
closing
coil
(
16
)
with
brass
tube
(
5
)
.
In
replacing
closing
coil
be
sure
to
replace
brass
tube
(
5
)
so
that
stationary
core
(
4
)
and
moving
core
(
22
)
are
aligned
in
the
tube
.
Be
careful
not
to
disturb
or
bend
plunger
(
23
)
.
Re
-
assemble
closing
coil
and
details
in
reverse
order
from
removal
.
CAUTION
:
All
power
should
be
removed
when
changing
,
maintaining
or
adjusting
contacts
.
OPERATING
MECHANISM
If
the
circuit
breaker
is
permanently
mounted
near
the
floor
so
that
the
closing
coil
cannot
be
dropped
far
enough
for
removal
then
follow
these
directions
.
Trip
breaker
and
remove
breaker
manual
operating
handle
and
breaker
face
plate
.
Disconnect
closing
coil
leads
from
control
cir
-
cuit
wiring
.
Take
off
bolts
(
18
)
,
washers
(
19
)
,
relay
release
arm
(
17
)
,
bolts
(
10
)
,
washers
(
11
)
and
plate
(
2
)
.
Drop
closing
coil
(
16
)
with
brass
tube
(
5
)
so
that
pin
(
6
)
is
exposed
.
Push
pin
(
6
)
to
right
into
hole
on
right
hand
side
of
solenoid
yoke
(
1
)
and
allow
moving
core
(
22
)
to
drop
into
brass
tube
(
5
)
.
Pick
up
closing
The
operating
mechanism
(
see
Fig
.
3
)
is
non
-
adjustable
and
consists
of
a
series
of
non
-
ferrous
links
designed
to
secure
low
closing
and
tripping
forces
.
To
check
for
friction
,
raise
the
trip
bar
and
slowly
rotate
the
manual
operating
handle
in
close
and
trip
direction
.
The
linkage
should
follow
the
handle
without
sticking
.
A
small
quantity
of
lubricant
is
placed
on
the
handle
shaft
,
the
roller
lever
roller
,
and
the
latch
plate
at
the
factory
.
I
10
Courtesy of NationalSwitchgear.com

DB
”
AIR
CIRCUIT
BREAKER
tt
coil
with
brass
tube
and
moving
core
and
bring
out
through
the
U
-
shaped
foot
on
breaker
.
Do
not
lose
plunger
(
24
)
and
plug
(
27
)
in
moving
core
(
22
)
.
To
replace
closing
coil
be
sure
plunger
(
24
)
and
plug
(
27
)
are
in
moving
core
(
22
)
and
re
-
assemble
closing
coil
and
details
in
reverse
order
from
removal
.
Take
care
to
align
sta
-
tionary
core
(
4
)
and
moving
core
(
22
)
in
brass
tube
(
5
)
.
Take
care
to
align
plunger
(
24
)
and
plug
(
27
)
with
plunger
(
23
)
.
The
minimum
permissible
control
voltages
at
the
terminal
of
the
closing
coil
,
and
the
closing
currents
at
normal
voltage
are
listed
in
Table
No
.
2
shown
on
Page
7
.
OVERCURRENT
TRIPPING
DEVICE
The
over
cur
rent
trip
is
an
air
delayed
device
that
can
be
supplied
with
various
rating
coils
ranging
from
100
to
1600
amperes
.
The
con
-
STEEL
PANEL
-
ARC
CHUTE
DB
-
50
CIRCUIT
BREAKER
>
600
AMPERES
.
600
VOLTS
A
-
C
6
POLE
UNIT
i
MECHANISM
X
]
TRIP
SCREW
MOVING
CONTACT
HINGE
UPPER
COIL
TERMINAL
X
]
:
LOWER
STUD
0
\
\
\
K
/
A
X
\
LOWER
COIL
TERMINAL
\
N
\
_
\
N
.
\
CLOSING
SOLENOID
'
OVERCURRENT
TRIPPING
DEVICE
_
•
CLOSED
TRIPPED
OPEN
(
RESET
)
Fig
.
3
—
Cross
-
Secff
oner
/
View
of
Type
DB
-
50
Circuit
Breaker
11
Courtesy of NationalSwitchgear.com

MAINTENANCE
i
ROLLER
LEVER
”
MECHANISM
FIRST
TOGGLE
LEVER
PUSH
TRIP
0
P
|
EN
X
~
r
-
l
CROSS
HANDLE
i
BAR
\
!
MM
\
3
v
TRIP
L
^
y
*
7
vJ
i
Jr
i
ir
\
;
<
-
K
4
,
-
"
V
V
-
V
:
'
-
'
r
r
/
Z
777
T
C
>
-
r
-
'
feir
PUSH
ROD
a
rx
/
y
xxx
zzzzzzi
I
I
/
/
x
x
i
i
i
i
i
/
\
/
t
LIFT
LINK
-
/
at
’
-
"
-
)
/
/
_
JRIP
I
/
*
/
/
/
a
/
BAR
t
/
/
1
/
/
TOGGLE
LINK
V f
LATCH
PLATE
/
PUSH
UNK
-
II
/
IF
T
sm
UPPER
SPRING
GUIDE
i
i
i
i
i
i
i
i
SPRING
\
i
LOWER
SPRING
GUIDE
^
i
t
i
l
i
N
aw
\
^
-
SPRING
MECHANISM
I
Xflgg
Fig
.
3
A
—
Type
DB
-
50
Spring
Closing
Mechanism
12
Courtesy of NationalSwitchgear.com

DB
”
AIR
CIRCUIT
BREAKER
i
f
struction
,
except
for
the
coils
,
is similar
for
all
ratings
.
this
position
by
means
of four
hexagon
head
steel bolts
2
-
1
/
2
inches
long
Fig
.
3
.
head
of
each
of
the
bolts
.
Care
should
be
taken
to
make
sure
that
bolts
longer
than
specified
above
are
not
used
,
because the
ends
of
the
bolts
may
bottom
in
coil
terminal
thereby
caus
-
ing
a
loose
connection
.
shown
at
A
,
Use
only
one
lock
washer
under
the
The
overcurrent
tripping
device
can
easily
be
removed
from
the breaker and
replaced
with
another
unit
of
different
rating
or
of
the
same
rating
without
affecting
the calibrations
.
Installation
and
Removal
Finally
,
the
trip
screw
mounted
on
the
trip
finger
above
the
unit
must
be
adjusted
for
proper
tripping
.
While
doing
this
,
be
sure
that
the
breaker
is
disconnected
from
the
circuit
.
Then
,
adjust
special
spacing
tool
S
#
1649025
to
the
exact
dimension
A
,
Fig
.
6
,
as
measured
previously
.
Set
this
spacing
tool with
correct
dimension
on
the
top
bearing
nut
of
the
over
-
current
trip
directly
under
the
trip
screw
.
Then with
the
breaker
closed and
by
means
of
special
wrench
S
#
1649026
,
turn
the
trip
screw
very
carefully
and
slowly
in
the
clockwise di
-
rection until the
breaker
just
trips
.
From
that
point
,
continue
turning
the
trip
screw
another
one
-
half
turn
.
This
half
turn
will
provide
1
/
64
inch
of
overtravel
which
insures
positive
trip
-
ping
of
the
circuit
breaker
.
This
adjustment
can
most
easily
be
made
by holding
the
spac
-
ing
tool
in
place
with
the
left
hand
and
turning
the
trip
screw
by
means
of
special
wrench with
the
right
hand
.
These tools should be inserted
from
the
bottom
and
care
taken
to
avoid
jam
-
ming
these
in
the
mechanism
or
contacts
when
the breaker
opens
.
Before
installing
the
overcurrent
tripping
de
-
vice
to
the
circuit
breaker
,
determine the
max
-
imum
travel
of
the
trip
plunger
as
shown
at
A
Fig
.
6
.
Trip
units
shipped
separately
are
labeled
with this
travel
.
To
measure
the travel
first
remove
the scale
plate
by
pushing
down
and
in
at
the bottom
of
the
plate
.
Then
,
while
releasing
the
instantaneous
or
short
delay
valve
by
raising
their
armature
,
push
the
moving
core
assembly
to
its maximum
upward
position
.
This
can
be
done
by prying
upward
with
a
screw
driver
in
-
serted
under the
long
delay
pick
-
up
lever
.
In
this
position
,
measure
the
maximum
travel
of
the
trip
plunger
above
the
top
bearing
nut
as
shown
at
A
Fig
.
6
.
Replace
the scale
plate
and unit is
then
ready
for
assembly
to
circuit
breaker
.
To
install the
overcurrent
trip
to
the
circuit
breaker
it
is
merely
necessary
to
insert
the
device
into
the
pole
unit
so
that
the
upper
coil
terminal
makes
contact
with the lower
part
of
the
moving
contact
hinge
and the
lower
coil
terminal
contacts
the
lower breaker stud
as
shown
in
Fig
.
3
.
The
unit
is
then
bolted
in
This
adjustment
duplicates
the
one
made
at
the
factory
for
calibration
of
the
timing
points
A
—
i
*
B
Fig
.
4
—
Series Overcurrent
Tripping
Device
with
Long
Time
and
Instantaneous
Element
Fig
.
5
—
Series
Overcurrent
Trip
-
ping
Device
Showing
the
Assem
-
bly
of
Calibration
Case
to
Mag
-
netic
Circuit
.
13
Courtesy of NationalSwitchgear.com

s
MAINTENANCE
i
\
Fig
.
6
—
Cross
-
Sectional
View
of
Series
Overcurrent
Tripping
Device
with
Long
Delay
and
Instantaneous
Elements
CURRENT
PERCENT
OF
COIL
RATING
100
POP
10.000
100.000
JO
1000
,
1000
5
*
<
\
^
LONG
DELAY
PICK
-
UP
ADJ
.
/
/
7
/
/
too
100
E
2
s
/
—
LONG
DE
^
AY
,
CLEARING
TIME
/
/
7
?
>
<
Ig
I
22
RESETTABLE
DELA
1
zv
to
to
/
-
±
s
z
/
z
n
TRIPPING
CHARACTERISTICS
OF
OB
-
50
OVERCURRENT
TRIP
DEVICE
WITH
LONGTIME
DELAY
AND
INSTANTANEOUS
ELEMENTS
.
INCLUDING
ARCING
TIME
.
I
O
.
INSTANTANEOUS
PICK
-
UP
o
2
ui
,
/
u
>
PI
/
z
o
f
2
I
LL
)
s
X
p
/
/
g
^
Sgr
^
B
^
^
^
ISjyE
DURATION
WHICH
BREAKER
MAY
TRIP
EVEN
THOUGH
fAULT
CURRENT
MAY
_
SUBSIDE
TO
A
VALUE
LESS
THAN
|
BO
%
BREAKER
RATING
.
HOWEVER
,
IF
FAULT
CURRENT
SUBSIDES
IN
LESS
.
pTHAN
RESETTABLE
DELAY
,
THE
BREAKER
WILL
NOT
TRIP
A
NO
THE
DELAYING
DEVICE
WILL
RESET
.
TOTAL
CLEARING
TIME
/
\
z
12
CYCLES
/
/
\
.
1
«
CYCLES
.
1
iPPL
!
CABLE
T
0
-
-
INTERRUPTING
\
J
RATING
'
Z
S
CYCLES
-
/
WMM
lO
.
OoO
'
7
.
C
&
/
/
/
/
/
/
/
/
IOO
,
cS
)
jOi
10
lOO
CURRENT
PERCENT
OF
COIL
RATING
I
Fig
.
7
—
Tripping
Characteristics
of
Standard
Series
Overcurrent
Tripping
Device
with
Long
Delay
and
Instantaneous
Elements
14
Courtesy of NationalSwitchgear.com

DB
”
AIR
CIRCUIT
BREAKER
i
t
on
the
unit
.
Since
the
trip
plunger
travel
to
Wi
&
o
trip
the
breaker
is
a
direct
function
of
the
tripping
time
,
it
is
important
that
this
adjust
-
ment
be
made
with
care
and
precaution
.
CURRENT
PERCENT
OF
COIL
RATING
IOOOQ
oco
JO
100
C
\
II
!
X
LONG
OELAY
PICK
-
UP
ADJ
.
To
remove
an
overcurrent
tripping
device
from
the
breaker
,
remove
the
four
bolts
A
Figure
3
which
hold
the
tripping
device
to
the
breaker
base
.
Before
removing
the
last
bolt
,
hold
the
tripping
device
to
prevent
it
from
,
0
falling
.
100
100
\
\
v
N
x
X
LONG
DELAY
ADJ
.
X
t
N
77
\
SHORT
OELAY
PICK
-
UP
.
AD
.
\
s
?
Construction
z
The
over
cur
rent
tripping
device
is
air
delayed
s
with
all
of
its
elements
completely
adjustable
.
A
typical
unit
is
shown
ready
for
mounting
on
a
circuit
breaker
pole
unit
in
Figure
4
.
%
s
s
s
p
s
s
m
/
SHORT
DELAY
ADJ
.
\
f
MAXl
'
'
3
I
/
MUM
g
^
»
TRIPPING
CHARACTERISTICS
OF
”
08
-
80
OVERCURRENT
TRIPPING
—
0
EVKJE
WITH
LONS
DELAY
AND
—
SHORT
OELAY
ELEMENTS
.
S
ui
1
*
vv
>
*
30
CYCLES
-
I
1
”
I
K
IS
THE
1
CURRENT
FLOW
,
RCSETTAALE
DELAY
IS
THE
~
DURATON
OF
FAULT
CURRENT
FLOW
AFTER
—
WHICH
BREAKER
MAY
TRIP
EVEN
—
THOUGH
FAULT
CURRENT
MAY
SUBSIDE
TO
A
VALUE
LESS
THAN
00
%
BREAKER
RATING
.
HOWEVER
.
—
IF
FAULT
CURRENT
SUBSETS
IN
LESS
THAN
RESETTABLE
DELAY
.
THE
BREAKER
WILL
NOT
TRIP
AND
THE
—
DELAYING
DEVICE
WILL
RESET
.
\
\
IS
CYCLES
-
\
X
1
I
I
INCLUDING
AROMG
TIME
/
1
»
r
>
ITNIE
i
i
4
—
6
CYCL
n
c
/
\
/
X
77
z
/
The
tripping
device
consists
of
two
main
sub
-
assemblies
namely
:
/
.
i
a
77
/
/
7
,
y
/
/
/
MINIMUM
6
AND
~
V
^
3
CYCtW
-
rwA
y
/
/
/
/
//
/
/
/
%
^
y
/
y
/
yy
/
/
/
/
AYCIIEI
2
u
XI
CYCLE
-
1
.
The
magnetic
frame
and
coil
assembly
as
shown
in
Figure
5
A
.
E
9
ETTABLE
DELAY
I
I
I
tOQf
&
0
,
000
1000
100
TO
CURRENT
PERCENT
OF
COIL
RATING
2
.
The
delay
elements
assembly
as
shown
in
Figure
5
B
.
The
two
assemblies
are
held
to
-
gether
by
means
of
the
two
white
mounting
screws
as
seen
from
the
bottom
of
the
cali
-
bration
case
.
Fig
.
8
—
Tripping
Characteristics
of
Selective
Series
Overcurrent
Tripping
Device
with
Long
Delay
and
Short
Delay
Elements
OMftENT
PERCENT
OP
COIL
RATINE
As
seen
from
the
sectional
view
Figure
6
,
the
magnet
frame
and
coil
assembly
consists
of
a
yoke
,
a
coil
,
a
stationary
and
moving
core
together
with
their
necessary
insulation
.
ii
j
i
Tttf
#
00
400
400
too
too
^
The
delay
elements
assembly
as
seen
from
the
same
figure
contains
an
air
chamber
,
a
40
diaphragm
,
and
trip
plunger
as
well
as
all
the
armatures
,
springs
,
and
valves
to
produce
the
adjustable
long
delay
,
short
delay
and
instan
-
ts
i
taneous
characteristics
of
the
circuit
breaker
:
i
4
I
to
tripping
curve
.
’
4
INSTANTANEOUS
PtCN
-
HP
AtJNSTASLK
SO
TO
WO
%
*
SOIL
SATINS
I
<
*
•
s
s
«
s
Time
-
Current
Classification
The
overcurrent
tripping
devices
can
be
sup
-
plied
with
any
combination
of
the
three
tripping
•
*
elements
,
namely
,
long
delay
,
short
delay
,
and
instantaneous
elements
.
The
most
popular
corn
-
et
binations
are
listed
below
:
.
oo
-
t
TOTAL
CLEAR
INS
1
.
TIME
It
CTCLlt
.
1
CYCLES
.
APPLICAOLI
TO
.
INTESSNPTINt
RATIWO
.
00
.
OS
1
CYCLE
*
«
04
.
04
»
i
1
—
DUAL
OVERCURRENT
SERIES
TRIPPING
DEVICE
%
y
.
os
.
ot
I
'
/
r
/
/
'
/
X
<
/
/
s
'
/
This
unit
has
an
adjustable
long
delay
and
an
adjustable
instantaneous
element
,
the
character
-
istic
curve
of
which
is
shown
in
Figure
7
.
y
.
01
.
01
IOOOO
WO
00
«
10
«
I
0
«
0
Fig
.
9
—
Tripping
Characteristics
of
Special
Series
Overcurrent
Tripping
Device
with
Instantaneous
Element
Only
15
Courtesy of NationalSwitchgear.com

MAINTENANCE
i
D
A
<
>
f
<
>
/
}
>
(
»
>
>
>
Fig
.
10
—
$
chemof
/
c
Diagram
of Standard
Overcurrent
Tripping
Device
with
Adjustable
Long
Delay
and
Adjustable
Instantaneous
Element
/
F
/
K
/
E
T
*
/
\
*
I
i
\
P
N
The
calibration
for
the
various elements
are
:
The calibration
for
the
various elements
are
:
(
a
)
Long
delay
pick
-
up
Adjustable
with calibrated
marks
at
80
-
100
-
120
-
140
and
160
percent
of
coil
rat
-
(
a
)
Long
delay
pick
-
up
Adjustable
with
calibrated marks
at
80
-
100
-
120
-
140
and
160
percent
of
coil
rat
-
ing
.
ing
.
(
b
)
Long
delay
Adjustable
with
one
calibrated
mark
at
25
seconds
(
limits
19
-
25
seconds
)
.
(
b
)
Long
Delay
The
long delay
is
available
with
any
one
of
the
delay
ranges
listed below
:
Delay
Range
Description
Adjustable
with
one
calibrated
mark
at
60
seconds
and another
at
30
seconds
or
less
.
Adjustable
with
one
calibrated
mark
at
5
seconds and another
at
25
seconds
or
less
.
Adjustable
with
one
calibrated
mark
at
40
seconds and another
at
20
seconds
or
less
.
Adjustable
with
one
calibrated
mark
at
30
seconds and
another
at
15
seconds
or
less
.
Adjustable
with
one
calibrated
mark
at
20
and
another
at
10
seconds
or
less
.
Adjustable
with
one
calibrated
mark
at
10
seconds and
another
at
5
seconds
or
less
.
60
(
c
)
Instantaneous
pick
-
up
Adjustable
with
one
calibrated
mark
at
1000
percent
of
coil
rating
.
'
i
50
40
2
—
DUAL
SELECTIVE
OVERCURRENT
SERIES
TRIPPING DEVICE
FOR GROUP
OR
TIE
BREAKERS
30
20
A
selective device
is
equipped
with
an
adjust
-
able
long
delay
and
an
adjustable
short
delay
element
.
These
two
elements
combine
to
give
atypical
selective
curve
as
shown
in
Figure
8
.
This
unit
can
be made
selective
with
a
stand
-
ard
device
or
another selective device
of
the
same
or
of
a
different
rating
.
10
(
c
)
Short
delay
pick
-
up
Adjustable
with
calibrated
marks
at
500
-
750
and
1000
percent
of
coil
rating
.
(
16
Courtesy of NationalSwitchgear.com

DB
”
AIR
CIRCUIT
BREAKER
»
«
moving
core
C
to
be
attracted
and
move
toward
the
stationary
core
B
.
At
low
currents
,
the
moving
core
C
will
carry
the
tripping
stem
F
along
with
it
,
immediately
closing
reset
valve
G
after
which
motion
is
retarded
by
the
dia
-
phragm
E
.
The
rate
of
travel
of
the
diaphragm
is
determined
by
the
rate
at
which
air
is
per
-
mitted
to
enter
chamber
T
by
the
various
valves
H
and
K
.
At
higher
currents
when
the
attrac
-
tion
between
the
moving
core
C
and
the
station
-
ary
core
B
is
greater
than
the
load
on
the
spring
inside
the
moving
core
,
the
moving
core
will
compress
the
spring
and
travel
independ
-
ently
of
the
tripping
stem
F
.
This
spring
in
-
sures
a
constant
force
pattern
acting
on
the
diaphragm
E
.
(
d
)
Short
delay
Adjustable
with
calibrated
marks
at
6
-
15
and
30
cycles
.
3
—
DUAL
SELECTIVE
OVERCURRENT
SERIES
TRIPPING
DEVICE
FOR
LOAD
BREAKERS
This
device
is
equipped
with
an
adjustable
long
delay
and
an
adjustable
instantaneous
ele
-
ment
.
The
calibration
for
the
various
elements
are
:
i
I
(
a
)
Long
delay
pick
-
up
Adjustable
with
calibrated
marks
at
80
-
100
-
120
-
140
and
160
percent
of
coil
rat
-
ing
.
(
b
)
Long
Delay
The
long
delay
is
available
with
any
one
of
the
delay
ranges
listed
below
:
Valve
H
is
the
long
delay
valve
and
it
is
per
-
manently
open
to
a
calibrated
setting
.
This
setting
which
controls
the
tripping
time
can
be
changed
by
means
of
dial
S
,
Figure
10
.
The
magnitude
of
current
at
which
the
long
delay
will
begin
to
operate
is
determined
by
the
long
delay
pick
-
up
adjusting
knob
P
Figure
10
.
The
magnitude
of
current
at
which
the
instantaneous
trip
will
operate
is
determined
by
the
instanta
-
neous
pick
-
up
adjusting
knob
N
Figure
10
.
Description
Adjustable
with
one
calibrated
mark
at
30
seconds
and
another
at
15
seconds
or
less
.
Adjustable
with
one
calibrated
mark
at
20
seconds
and
another
at
10
seconds
or
less
.
Adjustable
with
one
calibrated
mark
at
10
seconds
and
another
at
5
seconds
or
less
.
Delay
Range
30
20
10
2
—
DUAL
SELECTIVE
OVERCURRENT
SERIES
TRIPPING
DEVICE
FOR
GROUP
OR
TIE
BREAKERS
.
The
operation
of
this
selective
device
is
the
same
as
the
dual
overcurrent
series
tripping
device
except
that
in
this
case
,
the
instanta
-
neous
valve
K
,
Figure
10
is
replaced
with
a
short
delay
valve
J
,
Figure
11
which
controls
the
size
of
orifice
and
consequently
the
tripping
time
in
the
short
circuit
region
.
This
orifice
is
adjustable
by
means
of
knob
R
.
(
c
)
Instantaneous
pick
-
up
Adjustable
with
calibrated
marks
at
500
-
1000
and
1500
percent
of
coil
rating
.
4
—
SPECIAL
INSTANTANEOUS
TRIP
ONLY
This
device
is
equipped
with
an
adjustable
instantaneous
element
only
.
A
typical
time
-
current
characteristic
for
such
a
device
is
shown
in
Figure
9
.
3
—
SPECIAL
INSTANTANEOUS
TRIP
ONLY
DEVICE
The
special
instantaneous
trip
only
device
,
in
principle
,
is
the
simplest
of
the
four
.
As
seen
from
Figure
12
,
the
adjustable
instantaneous
trip
is
merely
a
modification
of
the
adjustable
long
delay
pickup
of
the
dual
overcurrent
series
tripping
device
.
This
device
is
available
with
either
of
the
two
calibrations
listed
below
:
(
a
)
Instantaneous
pick
-
up
Adjustable
with
calibrated
marks
at
80
-
100
-
120
-
140
and
160
percent
of
coil
rating
.
i
(
b
)
Instantaneous
pick
-
up
Adjustable
with
calibrated
marks
at
500
-
1000
and
1500
percent
of
coil
rating
.
Time
-
Current
Characteristics
The
time
current
curve
of
this
air
delayed
device
has
an
inverse
time
characteristic
up
to
approximately
500
per
cent
of
coil
rating
in
the
long
delay
range
as
shown
in
Figure
7
.
Within
this
range
,
the
moving
core
and
tripping
stem
move
as
a
unit
,
that
is
,
the
magnetic
pull
has
not
increased
sufficiently
to
overcome
the
loaded
spring
inside
the
moving
core
.
Above
Operation
1
—
DUAL
OVERCURRENT
SERIES
TRIPPING
DEVICE
AND
DUAL
SELECTIVE
OVERCURRENT
SERIES
TRIPPING
DEVICE
TOR
LOAD
BREAKERS
An
overload
or
short
circuit
current
through
the
series
coil
D
,
Figure
10
,
will
cause
the
17
Courtesy of NationalSwitchgear.com

MAINTENANCE
i
77
/
777
Fig
.
11
—
Schematic
Diagram
of
Selective
Series
Overcurrent
Tripping
Device
with
Adjustable
long
Delay
and
Short
Delay
Elements
]
[
]
[
]
[
I
*
P
Q
R
>
D
A
'
r
C
Fig
.
12
—
Schematic
Diagram
of
Specia
/
Series
Overcurrent
Tripping
Device
with
instantaneous
Element
Only
.
]
[
U
<
\
P
18
Courtesy of NationalSwitchgear.com

DB
”
AIR
CIRCUIT
BREAKER
»
t
2000
ID
Z
<
(
L
-
1
1500
O
a
h
-
z
UJ
o
a
:
1000
UJ
a
.
f
-
2
UJ
cr
cr
3
500
o
0
.
3
sc
o
0
-
0
1000
HIGH
LOW
SCALE SETTING
Ffg
.
13
—
tosfanfaneous
Pick
-
up
Percent
of
Coil
Rating
v
$
Coil
Settings
Obtained
by
Means
of Standard
Instantaneous
Adjusting
Knob
a
small
screw
driver
inserted
in
the slots
for
that
purpose
.
500
per
cent
,
the
tripping
time
is
essentially
constant
with increase
in
current
.
Within
this
region
,
the
magnetic
force
is
sufficient
to
over
-
come
the
spring
inside the
moving
core
at
the
outset
,
thereby
subjecting
the
diaphragm
to
the
constant
force
pattern
of
the
spring
.
The
tripping
time
will
remain
constant
until
interrupted
by
the instantaneous
or
short
delay
pick
-
up
wher
-
ever
they
occur
.
For
the
same reason
,
the
tripping
time
in
the short
delay
region
remains
constant
with
increasing
current
for
a
given
setting
of
the short
delay
.
2
—
LONG
-
DELAY
CALIBRATION
The
long delay
can
be
adjusted
by
means
of
the
long
time
adjusting
dial
S
Figure
10
,
also
shown
in
Figure
6
.
The
dial
adjustment
is
limited
to
slightly
less
than
one
turn
.
One
point
has
been
calibrated
at
the
factory
and
it
is
in
-
dicated
by
a
white
mark
on
the
outer
edge
of
dial
.
When
this white
mark
coincides
with
the
white
indicator
on
the
front
lower
case
the
tripping
time will be between
19
and
25
seconds
for
currents
above
500
per
cent
of
the
coil
rating
as
shown
in
Figs
.
7
and
8
.
Adjustment
of Calibration
Settings
CAUTION
:
As
a
safety
measure
,
the
breaker
should
be
disconnected
from
the circuit before
making
any
adjustment
.
3
—
INSTANTANEOUS
PICK
-
UP
The
instantaneous
pick
-
up
can
be
adjusted
by
means
of
knob
N
,
Figure
10
,
also
shown
in
Figure
6
.
The
instantaneous
pick
-
up
has been
calibrated
and the
calibration
plate
marked
at
10
times
the
coil
rating
at
the
factory
.
The
extremities
of
this scale
are
marked
"
High
"
and
"
Low
"
.
Various
pick
-
up
settings
below
and
above
10
times coil
rating
can
be
obtained
by
raising
or
Lowering
the indicator
by
means
of
the
adjusting
knob
.
The
adjusting
knob
can
be turned
by
hand
or
more
easily
turned with
a
small
screwdriver inserted
in
the slots
pro
-
vided
for
that
purpose
.
Figure
14
shows
the
approximate pick
-
up
currents
that
can
be
ex
-
pected
for
various scale
settings
below
and
above
the calibrated
setting
.
1
—
LONG
DELAY
PICK
-
UP
The
long
delay
pick
-
up
can
be
adjusted
by
means
of
P
,
Figure
10
,
also shown
in
Figure
6
.
The
unit
has
been calibrated
and
the cali
-
bration
plate
marked
at
five
settings
,
namely
80
,
100
,
120
,
140
and
160
per
cent
of
the coil
rating
.
Settings
slightly
below
80
per
cent
and
above
160
per
cent
as
well
as
intermediate
settings
although
not
calibrated
can
be
obtained
by
means
of
the
adjusting
knob
.
The
pick
-
up
was
placed
on
the
100
per
cent
setting
before
shipment
.
A
different
setting
can
be
obtained
by
turning
the
adjusting
knob
with
the
help
of
19
Courtesy of NationalSwitchgear.com

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C
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Solenoid
—
Construction
Details
Courtesy of NationalSwitchgear.com