Siemens SG-3118 Owner's manual

SIEMENS
Overcurrent
Trip
Devices
Instructions
Installation
Operation
Maintenance
SG
-
3118
Static
Trip
III
Courtesy of NationalSwitchgear.com

(
Safety
THIS
EQUIPMENT
CONTAINS
HAZARDOUS
VOLTAGES
.
SEVERE
PERSONAL
INJURY
OR
PROPERTY
DAMAGE CAN
RESULT
IF
SAFETY
INSTRUCTIONS
ARE
NOT FOLLOWED
.
ONLY
QUALIFIED
PERSONNEL
SHOULD
WORK ON
OR
AROUND
THIS
EQUIPMENT
AFTER
BECOMING
THOROUGHLY
FAMILIAR WITH
ALL
WARNINGS
,
SAFETY
NOTICES
,
AND
MAINTENANCE
PROCEDURES
CONTAIN
-
ED HEREIN
.
THE
SUCCESSFUL
AND
SAFE
OPERATION
OF
THIS
EQUIPMENT
IS
DEPENDENT
UPON PROPER
HANDL
-
ING
,
INSTALLATION
.
OPERATION
AND
MAINTENANCE
.
A
WARNING
h
Indicates
death
,
severe
personal
injury
or
substantial
property
damage
can
result
if
proper
precautions
are
not
taken
.
A
CAUTION
h
Indicates
minor
personal
injury
or
property
damage
can
result
if
proper
precautions
are
not
taken
.
Qualified
Person
For
the
purpose
of
this
manual and
on
product
labels
,
a
qualified
person
is
one
who is
familiar
with
the
installation
,
construction
and
operation
of
the
equipment
and
the
hazards
involved
.
In
addition
,
he has
the
following
qualifications
:
a
.
Is trained
and
authorized
to
energize
,
de
-
energize
,
clear
,
ground
and
tag
circuits and
equipment
in
accordance
with
established
safety
practices
.
b
.
Is trained
in
the
proper
care
and
use
of
protective
equip
-
ment
such
as
rubber
gloves
,
hard hat
,
safety
glasses
or
face
shields
,
flash
clothing
,
etc
.
,
in
accordance
with
established
safety
practices
.
A
DANGER
h
(
Indicates death
,
severe
personal
injury
or
substantial
property
damage
will
result
if
pro
-
per
precautions
are
not
taken
.
Field
Service
Operation
Signal
Words
Siemens
Energy
&
Automation
,
Inc
.
can
provide
competent
,
well
-
trained Field
Service
Representatives
to
provide
technical
guidance
and
advisory
assistance
for
the
installation
,
overhaul
,
repair
and
maintenance
of
Siemens
Energy
&
Automation
,
Inc
.
equipment
,
processes
and
systems
.
Contact
regional
service
centers
,
sales
offices
or
factory
for
details
.
Distinctive
signal
words
(
DANGER
,
WARNING
,
CAUTION
)
are
used
in
this instruction book
and
on
product
labels
to
indicate
degrees
of
hazard that
may
be encountered
by
the
user
.
These
signal
words
are
defined
below
.
Courtesy of NationalSwitchgear.com

able
of
Contents
(
Page
Page
13
TESTING
(
continued
)
Short
Time
Pickup
Test
Instantaneous
Trip
Test
Ground
Pickup
Test
Long
Time
Delay
Test
Thermal
Memory
Test
Short
Time
Delay
Test
Ground
Time
Delay
Test
Zone
Interlock
Test
Load
Indicator
Output
Test
Tripping
Actuator
Test
Current
Sensor
Test
Connections
Continuity
Checks
Excitation
Test
Sensor
Polarity
Primary
Current
Testing
MAINTENANCE
Removing
Static
Trip
III
from
Breaker
Repair
Cleaning
INTRODUCTION
General
Current
Sensors
Static
Trip
III
Device
OPERATIONS
Tripping
Actuator
Targets
Available
Types
Time
-
Current
Curves
Performance
In
Service
.
.
Settings
Time
Bands
General
Notes
Load
Indicator
Zone
Interlock
Coupler
.
.
.
Zone
Interlock
Expander
.
TESTING
General
Secondary
Current
Testing
Test
Connections
Long
Time
Pickup
Test
1
13
1
13
1
13
1
14
3
14
3
14
3
15
3
15
5
15
6
16
9
16
10
16
10
(
16
11
17
11
17
11
17
12
19
12
19
12
19
12
19
12
Note
The
instructions
contained
within
this
manual
are
necessary
for
the
safe
installation
,
maintenance
and
operation
of
this
equipment
.
If
this
manual
is
misplaced
or
lost
,
replacement
manuals
are
available
through
the
local
Siemens
Energy
&
Automation
,
Inc
.
sales
office
.
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
pro
-
blems
arise
which
are
not
covered
sufficiently
for
the
purchaser
'
s
purposes
,
the
matter
should
be
referred
to
the
local
Siemens
Energy
&
Automation
,
Inc
.
sales
office
.
THE
CONTENTS
OF
THIS
INSTRUCTIONAL
MANUAL
SHALL
NOT
BECOME
PART
OF
OR
MODIFY
ANY
PRIOR
OR
EXISTING
AGREEMENT
,
COMMITMENT
OR
RELATIONSHIP
.
THE
SALES
CONTRACT
CONTAINS
THE
ENTIRE
OBLIGATION
OR
SIEMENS
ENERGY
&
AUTOMATION
,
INC
.
THE
WARRANTY
CONTAINED
IN
THE
CONTRACT
BETWEEN
THE
PARTIES
IS
THE
SOLE
WARRANTY
OF
SIEMENS
ENERGY
&
AUTOMATION
,
INC
.
ANY
STATEMENTS
CONTAINED
HEREIN
DO
NOT
CREATE
NEW
WARRANTIES
OR
MODIFY
THE
EXISTING
WARRANTY
.
I
drawings
or
other
supplementary
instructions
for
specific
applications
are
forwarded
with
the
manual
or
separately
,
they
take
_
precedence
over
any
conflicting
or
imcomplete
information
in
this
manual
.
1
1987
^
Siemens
Energy
&
Automation
.
Inc
Courtesy of NationalSwitchgear.com

*
itroduction
Page
1
i
In
addition
to
the
basic
system
,
optional
devices
can
be
pro
-
vided
tor
additional
functions
.
These
include
:
The
information
contained
within
is
intended
to
assist
operating
personnel
by
providing
information
on
the
general
act
eristics
of
equipment
of
this
type
.
It
does
not
relieve
the
of
responsibility
to
use
sound
engineering
and
safety
prac
-
ihe
application
,
operation
and
maintenance
of
the
par
-
rfMf
1
.
A
Load
Indicator
mounted
on
the
front
cover
of
the
breaker
to
display
load
currents
and
provide
adjustable
load
alarm
contacts
.
IJCO
*
ii
iicuiar
equipment
purchased
.
it
drawings
or
other
supplementary
instructions
for
specific
ap
-
plications
are
forwarded
with
this
manual
or
separately
,
they
take
precedence
over
any
conflicting
or
incomplete
informa
-
tion
m
this
manual
.
ine
sales
contract
carries
all
the
information
on
warranty
coverage
.
2
Zone
Interlock
Coupler
and
Zone
Interlock
Expander
devices
to
connect
trip
devices
together
for
selective
short
time
and
ground
fault
interlocking
.
Current
Sensors
Toroidal
current
sensors
,
similar
to
standard
bushing
current
transformers
,
are
mounted
,
one
-
per
-
phase
on
the
primary
studs
of
the
circuit
breaker
.
They
are
special
purpose
current
transformers
that
have
the
accuracy
and
output
voltage
capabili
-
ty
needed
to
properly
operate
the
static
trip
device
.
These
pro
-
vide
a
signal
to
the
static
trip
device
proportional
to
the
primary
current
.
The
current
sensors
selected
for
a
specific
circuit
breaker
establish
the
maximum
continuous
current
rating
of
that
breaker
and
the
adjustment
range
.
Each
sensor
provides
a
choice
of
eleven
selectable
current
settings
.
General
Static
Trip
HI
is
the
name
of
Siemens
Energy
&
Automation
,
inc
microprocessor
based
static
overcurrent
trip
device
for
use
on
LA
and
RL
series
low
voltage
power
circuit
breakers
.
The
>
>
reakers
and
trip
device
are
listed
and
labeled
by
Underwriters
.
boratories
(
UL
)
.
With
the
exception
of
the
selector
switches
and
one
poten
-
tiometer
the
Static
Trip
ID
overcurrent
trip
devices
are
complete
-
ly
static
.
There
are
no
moving
parts
or
mechanical
contacts
.
Components
used
are
semiconductors
,
integrated
circuits
,
capacitors
,
transformers
,
etc
.
The
selector
switches
are
seal
-
ed
binary
coded
decimal
types
with
gold
plated
contacts
.
The
device
uses
an
eight
bit
single
chip
microprocessor
,
with
its
internal
ROM
(
Read
Only
Memory
)
programmed
to
be
a
trip
device
.
All
the
circuits
are
designed
for
conservative
loading
of
components
for
long
life
and
little
maintenance
.
The
rated
secondary
current
for
the
sensors
is
0.5
amperes
at
rated
primary
current
.
All
the
sensors
used
with
the
Static
Trip
III
device
are
encapsulated
in
polymeric
material
to
pro
-
tect
the
windings
and
prevent
their
motion
during
short
circuits
on
the
circuit
breaker
.
Static
Trip
III
Static
Tnp
Hi
overcurrent
trip
devices
operate
to
open
the
cir
-
cuit
breaker
when
the
circuit
current
exceeds
a
preselected
current
-
time
relationship
.
Depending
on
the
magnitude
of
the
overcurrent
and
the
selected
settings
,
tripping
may
be
instan
-
taneous
or
time
-
delayed
.
Energy
t
0
operate
the
tripping
system
is
obtained
solely
from
circuit
being
protected
.
Batteries
or
other
power
sources
im
not
needed
A
molded
polyester
enclosure
,
attached
to
the
breaker
,
houses
the
trip
device
and
its
electronic
circuits
(
Figure
1
)
.
The
static
tnp
device
receives
the
signal
from
the
current
sensors
.
It
monitors
the
signal
,
senses
overloads
and
faults
,
and
deter
-
mines
the
required
action
in
accordance
with
preselected
con
-
trol
settings
.
?
no
In
the
Static
Trip
III
device
the
current
signal
is
scaled
to
the
proper
value
internally
by
small
transformers
,
one
per
phase
,
rectified
and
converted
to
a
voltage
signal
by
a
resistor
.
This
voltage
signal
is
converted
to
a
digital
signal
by
an
analog
to
digital
converter
.
All
timing
and
logic
decisions
are
then
pro
-
cessed
mathematically
in
the
microprocessor
,
and
are
not
af
-
fected
by
variations
due
to
external
influences
,
such
as
changes
m
temperature
h
°
^
asic
static
overcurrent
trip
system
consists
of
three
parts
t
Primary
circuit
current
sensors
The
Static
Trip
III
device
t
A
in
.
xjnetically
held
circuit
breaker
latch
release
device
call
-
(
!
n
t
•
r
,
npmq
actuator
Courtesy of NationalSwitchgear.com

I
Courtesy of NationalSwitchgear.com

Operation
Page
3
Tripping
Actuator
The
tripping
actuator
for
use
with
the
Static
Trip
III
device
con
-
tains
an
additional
coil
which
,
when
energized by
an
additional
output
provided
by
the
trip
device
,
aids the
permanent
magnet
in
holding
the
actuator
closed
.
This coil
,
called
the
hold
-
in
coil
,
is
to
counteract
the
effects
of
the
external
magnetic
fields
pro
-
duced
by
short
circuit
currents
flowing
through
the
breaker
.
When the
static
trip
device
senses
a
circuit
condition
that
re
-
quires
the breaker
to
open
,
it
provides
an
output
to
the
actuator
(
Figure
2
)
which
causes
the
circuit breaker
contacts
to
open
and
isolate the
circuit
.
When the circuit
breaker
is
closed
,
the
tripping
actuator
is held
in
a
charged
position
by
a
permanent
magnet
.
It
contains
a
coil that
is
energized
by
the
output
of
the
static
trip
device
.
When
energized
this
coil
causes
the
magnetic
flux
to
shift
to
a
new
path
,
away
from
the
holding
pole
faces
.
This
releases
the stored
energy
of
a
spring
located inside
the
actuator
.
The
spring
pro
-
vides the
energy
to
trip
the
breaker
.
When
the
breaker
mechanism
opens
,
the
actuator
is
returned
to
the
charged
and
held
position
by
a
reset
mechanism
on
the
breaker
.
Targets
The
target
element consists
of
a
custom
LCD
(
Liquid
Crystal
Display
)
,
a
modest
amount
of
CMOS
logic
and
a
large
capacitor
(
1
Farad
)
to
store
the
power
to
operate
the
logic
and
LCD
for
an
extended
period
of
time
.
The
LCD
has
four
legends
that
become visible
when
the
target
is
operated
,
either
by
the
microprocessor
or
the
"
watchdog
”
circuit
.
The
four
legends
are
:
OVERLOAD
to
signal
long
time
tripping
,
SHORT
CIRCUIT
to
signal
either
short time
or
instantaneous
tripping
,
GROUND
FAULT
to
signal
when
the
device
trips
on
ground
current
,
and
DISABLED
to
signal
when
the
"
watchdog
”
circuit
determines
that the
microprossor
is
not
functioning
properly
.
Available
Types
Various
types
of
Static
Trip
III
devices
are
available
.
Similar
in
many
respects
,
they
differ
only
in
their
specific
application
.
All
accept
identical
current
sensor
input
and
provide
output
signals
to
the
tripping
actuator
,
and
to
the
optional
devices
.
The
type
designation
is
coded
to
indicate
the
functional
elements
and
is
preceeded
by
RMS
to
denote
the
standard
RMS
sensing
feature
.
The
type
coding
is
two
to
four
letters
as
shown
below
:
-
#
T
=
LONG
TIME
delay
element
.
S
=
SHORT
TIME
delay
element
.
I
=
INSTANTANEOUS
element
.
Figure
2
.
Tripping
Actuator
G
=
GROUND
FAULT
element
.
For
each
element
except
INSTANTANEOUS
,
there
are
two
ad
-
justable
selector
switches
,
accessible
through
the
front
cover
of
the
device
,
one
for
the
current
or
pickup
setting
and
one
for
the
time
delay
setting
.
The
INSTANTANEOUS
has
only
one
switch
for
pickup
setting
.
All
adjustments
can
be
made
in
the
field
.
Following
are
brief
descriptions
of
the
different
types
.
(
Courtesy of NationalSwitchgear.com

C
_
Operation
Page
4
Type
RMS
-
TI
A
dual
trip
device
used
for
phase
overcurrent
protection
with
instantaneous
trip
.
The
long
time
current
setting
range
is
selected
from
the
trip
rating
table and
is
switch
selectable
in
eleven
steps
from
0.5
to
1.0
times the
current
sensor
rating
.
The
pickup
value is
fixed
at
1.1
times
current
setting
.
The
LONG
TIME
delay
is selectable with
a
choice
of five
bands
.
The
long
time circuit
has
a
switch
-
selectable
"
Thermal
Memory
"
func
-
tion
for
motor
protection
.
The instantaneous element
is switch
selectable
in
six
steps
from
2
to
15
times the
current
sensor
rating
.
The instantaneous
pickup
setting
is
independent
of
the
long
time
current
setting
.
Type
RMS
-
TIG
-
T
A
dual
trip
device which
provides
phase
overcurrent
protec
-
tion
same
as
the
Type
RMS
-
TI
plus
ground
fault
protection
for
three wire
or
four
wire
circuits
on
systems
with either
phase
to
phase
or
phase
to
neutral
loading
.
Ground
pickup
settings
are
independent
of
the
phase
settings
and
are
selectable
in
5
steps
from
20
to
60
%
of
the
ground
sensor
rating
.
When
used
on
four
wire circuits
a
fourth
neutral
sensor
is
required
.
It is
mounted
in
the bus
compartment
and
is
wired
to
the
breaker
through
the
breaker
secondary
disconnects
.
Direct
ground
sensing
can
also be
used
,
with the
external neutral
sensor
mounted
on
the
ground
return
conductor
.
The
Ground
Fault
function
includes
an
I
*
t
ramp
in
the time
-
current
delay
characteristic
and
a
built
in
memory
for
arcing
ground
fault
protection
.
The device
contains
an
in
/
out
switch
for
long
time
"
Thermal
Memory
.
”
Type
RMS
-
TS
A
selective
trip
device used
for
phase
overcurrent
protection
which
provides
time
delay
tripping
only
.
It
allows
complete
field
adjustment
of
long
time
delay
and
current
setting
plus
the
short
time
delay
and
pickup
.
The
short
time
pickup
can
be
selected
in
8
steps
from
2
to
12
times
the
long
time
current
setting
.
Any
ie
of
the
five
short
time
delay
bands
can
be
chosen
to
be
^
jsed
with
any
of
the
five
long
time
delay
bands
.
The device
contains
in
/
out
switches
for
short
time
Pt
ramp
and
long
time
"
Thermal
Memory
.
"
Type
RMS
-
TSG
-
T
A
selective
trip
device
which
provides
phase
overcurrent
pro
-
tection
same
as
Type
RMS
-
TS
plus
ground
fault
protection
for
3
-
wire
or
4
-
wire
circuits
on
systems
with
either
phase
to
phase
or
phase
to
neutral
loading
.
Ground
current
pickup
settings
are
independent
of
the
phase
pickup
settings
and
are
adjustable
from
20
to
60
%
the
ground
sensor
rating
.
When used
on
4
-
wire
systems
a
fourth
neutral
sensor
is
required
.
It is mounted
in
the
bus
compartment
is
wired
to
the breaker
through
the
breaker
secondary
disconnects
.
The
ground
element
can
also
be
con
-
nected
for
direct
ground
sensing by
mounting
the
external
neutral
sensor
on
the
switchgear
ground
return
conductor
.
The
device
contains
an
in
/
out
switch
that
adds
an
Pt
ramp
to
the short
time
delay
bands
.
The device contains
an
in
/
out
switch
for
long
time
"
Thermal
Memory
.
"
Type
RMS
-
TSI
A
triple
selective
trip
device
used
for
phase
overcurrent
pro
-
tection
which
provides
long
time
delay
,
short
time
delay
and
instantenous
elements
.
It
allows
complete
adjustment
of
the
long
time
delay
band
and
current
setting
,
the short
time
delay
band
and
pickup
and the
instantaneous
pickup
.
The
short
time
pickup
can
be
adjusted
from
2
to
12
times the
long
time
current
setting
.
The
instantaneous
pickup
can
be ad
-
justed
from
2
to
15
times the
current
sensor
rating
.
The instan
-
taneous
pickup
current
is
not
changed by
a
change
in
the
long
time
current
setting
.
The short
time
pickup
varies
with
long
time
current
setting
.
Any
one
of
the short time
delay
bands
can
be
chosen
to
be used
with
any
one
of
the
long
time bands
.
The
device
contains
in
/
out
switches
for
short time
Pt
ramp
and
long
time
"
Thermal
Memory
.
"
Type
RMS
-
TSIG
-
T
A
triple
selective
trip
device
which
provides
phase
overcurrent
protection
same
as
Type
RMS
-
TSI
plus
ground
fault
protection
for
3
-
wire
or
4
-
wire
circuits
on
systems
with
either
phase
to
phase
or
phase
to
neutral
loading
.
Ground
current
pickup
is
independent
of
the
phase
current
settings
.
The
ground
pickup
settings
are
selectable
from
20
to
60
%
of
the
ground
sensor
rating
.
When
used
on
4
-
wire
circuits
a
fourth
neutral
sensor
is
required
.
It
is
mounted
in
the
bus
compartment
and
is
wired
to
the breaker
through
the
breaker
secondary
disconnects
.
Types
RMS
-
TI
-
T
,
RMS
-
TS
-
T
and
RMS
-
TSI
-
T
Targets
are
provided
by
adding
a
"
*
T
"
suffix
to
the basic
trip
device
catalog
number
.
The
same
basic
protective
functions
"
re
provided
as
described above
.
In
addition
,
a
separate
coprocessor
"
watchdog
”
circuit is included
to
monitor and
ndicate
malfunction
of
the
microprocessor
.
/
Courtesy of NationalSwitchgear.com

(
~
Operation
Page
5
Types
RMS
-
TS
-
TZ
,
RMS
-
TSI
-
TZ
,
RMS
-
TSIG
-
TZ
and
RMS
-
TSG
-
TZ
on
the
band
selected
.
In
other
words
,
the
delay
for
a
given
band
setting
varies
inversely
as
the
square
of
the
current
.
When
plot
-
ted
on
log
-
log
paper
this
relationship
is
a
straight
line
as
shown
by
the
sloping
bands
in
Figure
3
.
Five
discrete
long
time
delay
bands
are
available
in
every
device
,
any
one
of
which
may
be
selected
by
the
delay
band
control
switch
.
The
"
Z
”
suffix
at
the
end
of
the
trip
device
catalog
number
signifies
Zone
Interlocking
capability
for
short
time
and
/
or
ground
fault
functions
.
The
same
basic
protective
functions
are
provided
as
described
above
with
the
added
capability
of
con
-
necting
trip
devices
together
into
a
selectively
Zone
Interlock
-
ed
system
.
The
Zone
Interlock
circuit
has
an
in
/
out
switch
to
allow
these
trip
devices
to
act
as
standard
units
.
This
facilitates
testing
and
allows
interchange
with
trip
devices
which
are
not
Zone
Interlocked
.
The
long
time
element
has
a
"
Thermal
Memory
"
function
that
is
selected
by
a
switch
on
the
front
of
the
device
.
If
this
switch
is
"
in
.
"
the
delay
counter
of
the
long
time
circuit
will
not
reset
to
zero
when
the
current
falls
below
the
long
time
pickup
value
,
but
will
slowly
count
down
at
a
rate
determined
by
the
magnitude
of
the
remaining
current
.
When
there
is
an
intermit
-
tant
overload
that
does
not
reach
the
pickup
level
of
the
short
circuit
elements
,
the
intervals
of
overload
current
will
be
ac
-
cumulated
and
tripping
will
occur
when
the
accumulated
value
reaches
the
selected
trip
time
.
However
,
if
the
current
drops
to
nearly
zero
the
count
will
be
reset
and
the
timer
will
require
the
full
delay
before
tripping
will
occur
.
NOTE
1
.
Devices
that
provide
ground
fault
protection
are
not
available
without
targets
.
2
.
Optional
Selective
Zone
Interlocking
circuits
are
"
hard
wired
"
between
trip
devices
.
When
this
op
-
tion
is
specified
the
trip
device
is
provided
with
a
cord
to
connect
to
a
cubicle
-
mounted
connector
.
The
trip
device
provides
an
output
signal
whenever
either
the
ground
or
short
time
element
picks
up
.
This
output
signal
is
connected
from
the
downstream
breaker
to
the
input
terminals
of
the
upstream
breaker
.
3
.
With
no
signal
applied
to
the
Zone
Interlocking
in
-
put
and
the
Zone
Interlock
switch
"
in
.
"
both
the
ground
and
the
short
time
elements
will
operate
on
their
shortest
time
delay
bands
,
regardless
of
the
band
selected
.
When
the
signal
is
applied
both
the
ground
and
the
short
time
elements
will
operate
on
their
selected
delay
bands
.
If
the
"
Thermal
Memory
"
switch
is
"
out
,
"
the
long
time
element
will
reset
each
time
the
current
falls
below
the
long
time
pickup
value
.
The
minimum
delays
for
each
band
,
at
six
times
the
current
setting
are
3.5
,
6.0
,
10
,
17
and
30
seconds
,
and
are
shown
at
the
delay
adjustment
switch
.
The
short
-
time
element
has
a
definite
delay
which
is
indepen
-
dent
of
current
as
shown
by
the
horizontal
curves
in
Figure
3
.
There
are
5
calibrated
bands
.
These
have
nominal
delays
of
0.08
,
.
15
,
.
22
,
.
30
and
.
40
seconds
.
The
short
time
element
has
an
I
*
t
ramp
as
shown
in
Figure
3
.
This
function
is
selected
in
or
out
by
a
small
switch
on
the
front
of
the
device
labeled
"
Short
Time
Pt
.
"
This
feature
provides
improved
coordination
with
downstream
devices
such
as
time
delay
fuses
,
or
molded
case
circuit
breakers
.
The
ground
fault
time
delay
element
has
a
definite
delay
similar
to
the
short
time
element
.
There
are
three
calibrated
bands
hav
-
ing
delays
of
0.1
second
,
0.25
second
and
0.4
second
.
The
ground
fault
element
also
includes
an
I
2
t
ramp
as
shown
in
Figure
3
.
Time
-
Current
Curves
Figure
3
is
a
set
of
time
-
current
curves
for
the
Static
Trip
III
devices
.
The
tong
time
element
has
a
characteristic
represented
by
:
T
=
KI
-
2
or
=
K
/
I
2
where
T
=
time
delay
.
I
=
current
expressed
in
multiples
of
the
long
time
current
setting
,
and
K
is
a
constant
depending
(
Courtesy of NationalSwitchgear.com

operation
Page
6
0
formal
coating
to
exclude
moisture
and
many
corrosive
at
-
mospheres
.
However
,
the
factory
should
be
consulted
when
the
application
involves
a
particularly
severe
environment
.
Both
the
short
time
and
the
ground
fault
elements
can
be
sup
-
plied
to
be
used
with
the
Zone
Interlock
option
.
The
Z
1
option
allows
the
trip
devices
to
be
wired
together
to
provide
faster
tripping
for
faults
between
breakers
.
When
Zone
Interlocking
is
specified
,
the
trip
device
will
operate
on
the
minimum
time
delay
curves
for
both
short
time
and
ground
fault
in
the
absence
of
an
incoming
Zl
signal
.
When
the
trip
device
is
supplied
with
an
incoming
Zl
signal
,
both
curves
will
shift
to
the
bands
selected
by
their
respective
delay
band
settings
.
The
temperature
at
the
static
trip
device
does
have
some
ef
-
fect
on
the
characteristics
and
on
the
overall
reliability
of
the
system
.
The
change
in
characteristics
is
small
since
most
of
the
operations
are
carried
out
as
mathematical
manipulations
within
the
microprocessor
,
so
changes
should
not
be
a
factor
in
most
applications
.
Over
the
range
of
-
40
°
C
to
+
55
°
C
(
-
40
°
F
to
131
°
F
)
,
the
variations
from
performance
at
room
temperature
is
very
small
,
amounting
to
less
than
5
%
on
pickup
or
time
delay
values
.
Operation
is
not
recommended
beyond
this
range
.
If
necessary
,
control
of
the
temperature
should
be
provided
by
heaters
or
ventilation
.
Operation
at
increased
am
-
bient
temperature
seriously
affects
the
reliability
of
all
electronic
devices
.
Trip
devices
with
the
Zone
Interlocking
option
have
an
"
in
/
ouf
switch
to
allow
them
to
function
as
a
standard
trip
unit
when
not
wired
into
a
Zl
system
.
Instantaneous
trip
has
no
intentional
time
delay
,
other
than
that
provided
by
the
power
supply
and
for
filtering
purposes
.
The
Instantaneous
curves
show
the
breaker
rated
clearing
time
for
a
three
phase
fault
.
For
closing
in
on
a
single
phase
fault
the
total
clearing
time
may
be
extended
by
as
much
as
.
02
seconds
.
Connection
Diagrams
Figure
4
through
6
show
in
schematic
form
the
pre
-
wired
connections
from
the
breaker
-
mounted
cur
-
rent
sensors
to
the
Static
Trip
III
device
.
This
wiring
varies
with
the
application
.
The
three
most
commonly
used
schemes
are
shown
,
and
the
diagrams
with
their
captions
are
self
-
explanatory
.
he
width
of
the
time
bands
in
Figure
3
is
due
principally
to
(
.
Terences
between
devices
caused
by
normal
tolerance
of
commercial
components
in
the
circuits
.
Repeated
tests
on
any
one
unit
will
fall
in
a
much
narrower
band
.
The
band
width
also
includes
the
breaker
interrupting
time
.
The
upper
limit
represents
the
maximum
total
clearing
time
including
breaker
opening
and
arcing
time
,
whereas
the
lower
limit
is
the
"
resettable
time
”
—
the
maximum
time
that
the
overload
can
persist
without
tripping
the
circuit
breaker
.
NOTE
For
4
-
wire
systems
with
ground
fault
tripping
the
neutral
sensor
is
connected
to
the
neutral
or
ground
return
conductor
in
the
bus
compartment
,
and
is
con
-
nected
to
the
Static
Trip
III
trip
device
through
secon
-
dary
drawout
contacts
on
the
breaker
.
Note
that
the
Instantaneous
curves
show
no
"
resettable
time
,
"
indicating
that
multiple
breakers
with
instantaneous
trip
devices
cannot
be
selectively
coordinated
for
short
circuits
except
by
pickup
settings
.
Performance
In
Service
Ambient
conditions
and
length
of
service
have
little
effect
on
the
performance
of
the
Static
Trip
III
trip
device
.
The
circuits
are
stable
and
will
show
excellent
repeatability
over
long
periods
of
time
.
Service
involving
frequent
operations
will
not
cause
the
characteristics
to
change
or
drift
,
since
there
are
no
moving
mechanical
parts
to
wear
or
bearings
to
lubricate
.
Static
Trip
III
devices
are
tolerant
of
dusty
conditions
and
will
function
properly
in
many
areas
that
would
affect
the
perfor
-
mance
of
electro
-
mechanical
trip
devices
.
The
circuit
boards
id
components
inside
the
trip
device
are
coated
with
a
con
-
(
Courtesy of NationalSwitchgear.com

(
aeration
Page
7
GROUND CURRENT
IN
PERCENT
OF GRD
,
SENSOR
RATING
40
60
80
100
CURRENT
IN
MULTIPLES
OF
LONG
TIME
SETTING
4
6
8
10
20
40
60
Mloo
10 20
\
800
800
600
600
-
LONG
TIME
CURVES
CD
V
\
400
400
LONG
TIME
CURRENT
SETTING
IS SVITCH
SELECTABLE
FROM
0.5
TO
1.0
TIMES SENSOR
RATING
VITH
CALIBRATED
POINTS
PER
DEVICE
FACEPLATE
\
200
200
%
GROUND
FAULT
PICKUP
ADJUSTMENT
20
,
30
,
40
,
50
&
60
'
/
.
OF GRD
.
SENSOR
RATING
100
100
80
80
\
5
s
X
5
cr
>
r
\
v
60
60
5
x
5
\
TIME DELAY
REFERENCE
POINTS
PER
DEVICE
FACEPLATE
X
40
i
\
20
\
\
IW
\
\
x
(
10
1
8
8
\
SHORT
TIME
PICKUP
ADJUSTMENT
RANGE
2.3
,
4
,
5.6
,
7
,
8
t
12
TIMES
LONG
TIME
CURRENT
SETTING
\
,
(
A
(
A
6
X
£
6
\
z
z
a
NA
\
\
5
\
a
4
4
u
<
J
Nil
UJ
LJ
(
A
(
A
N
v
SHORT
TIME
I
2
t
SVITCH
z
z
\
To
IN
2
2
yy yy y
LJ
UJ
OUT
\
\
z
z
\
\
X
\
GROUND
CURVES
(
G
)
VV
\
SHORT
TIME
-
CURVES
<
S
3
l
.
8
.
8
v
IV
\
y
V
x z
.
6
1
X
1
.
6
Z
5
X
X
>
\
V
)
U
\
lAO
\
.
4
.
4
m
x
v
h
\
V
{
s
\
\
22
V
\
.
2
.
2
A
\
\
\
I
x
r
r
-
.
10
.
1
\
.
08
.
08
.
06
k
y
.
06
p
7
INSTANTANEOUS
PICKUP
-
v
ADJUSTMENT
RANGE
2
,
4
,
6.0
,
12
t
15
TIMES
SENSOR
RATING
•
^
MAXIMUM
INTERRUPTING
TIME
.
04
.
04
.
02
.
02
.
01
.
0
{
10
20
40
60
80100
40
60 80
100
20
4
6 8
10
GROUND
CURRENT
IN
PERCENT
F
GRD
.
SENSOR
RATING
CURRENT
IN
MULTIPLES
OF
LONG
TIME
SETTING
Figure
3
.
Static
Trip
III
Trip
Device
Time
-
Current
Curves
Courtesy of NationalSwitchgear.com

(
Jperation
Page
8
CT
3
CT
2
CT
1
Wire
G
G
From
To
Size
Tl
No
.
Y Y
Y
—
C
1
CT
1
-
Y
CT
2
-
Y
CT
3
-
Y
CT
1
-
G
CT
2
-
G
CT
3
-
G
STD
1
STD
2
STD
3
CT
2
-
G
CT
3
-
G
STD
4
18
C
2
18
C
3
18
CO
18
S
~
Black
CO
.
18
OJ
CO
o
O
O
O
o
Red
~
x
CO
18
TA
1
STD
6
STD
7
STD
8
Black
TA
2
Red
<
o
1
2
3
4
5
6
TA
3
Blue
Figure
4
.
Static
Trip
ID
"
3
WG
”
Connection
Diagram
Wire
Size
From To
CT
3
CT
2
CT
1
No
.
G
G
Cl
CT
1
-
Y
CT
2
-
Y
CT
3
-
Y
CT
1
-
G
CT
2
-
G
CT
3
-
G
STD
1
STD
2
STD
3
CT
2
-
G
CT
3
-
G
STD
4
STD
4
STD
5
18
5
C
2
18
(
C
3
18
CO
18
CO
18
CM
CO
o
CO
18
Black
o
O
O
o
SO
2
18
Redjx
SD
1
SD
1
18
SD
2
\
TA
1
STD
6
STD
7
STD
8
Black
b
TA
2
Red
1 2
3
4
5
6
7
TA
3
Blue
Figure
5
,
Static
Trip
HI
“
4
WRG
"
Connection
Diagram
Wire
Size
To
From
CT
3
CT
2
CT
1
No
.
6
G
STD
1
STD
2
STD
3
CT
2
-
G
CT
3
-
G
STD
5
STD
4
STD
5
18
C
1
CT
1
-
Y
CT
2
-
Y
CT
3
-
Y
CT
1
-
G
CT
2
-
G
CT
3
-
G
SD
2
Y
Y
—
18
C
2
18
C
3
18
CO
18
CO
CM
CO
18
CO
O
O
o
s
’
Black
o
16
O
Red
"
x
SD
1
18
SD
1
SD
2
STD
6
STD
7
STD
8
Black
TA
1
b
Red
TA
2
TA
1
2
3
4
5
6
7
8
STD
TA
3
Blue
(
•
Device Leads
«
Figure
6
.
Static
Trip
III
* *
4
WDG
'
*
Connection
Diagram
Courtesy of NationalSwitchgear.com

Operation
Page
9
Settings
device is
set
on
1.0
it
will
pickup
and
start
timing
when
secon
-
dary
current
exceeding
0.55
ampere
is
supplied
by
the
cur
-
rent
sensors
.
EXAMPLE
:
Suppose
it
is
desired
that
the
breaker
shall
trip
whenever sustained
current
exceeds
600
amperes
,
and
sup
-
pose
the
current
sensor
rating
is
800
amperes
(
800
/
0.5
ratio
)
.
The
LONG
TIME
current
setting
should be
.
75
.
Static
Trip
III
devices have
a
number
of
switches that
can
be
arranged
to
select
discrete
load conditions
that
will
cause
the
breaker
to
open
.
The
settings
are
usually
made when
the
breaker is
placed
in
service
to
match
anticipated
load condi
-
tions
and coordination
requirements
.
Future
changes
are un
-
necessary
unless
load
conditions
change
or
primary
circuit
changes
are
made
.
Figure
7
is
an
illustration
of
the
type
RMS
-
TSIG
-
TZ
device
which
contains
all
Static
Trip
III
control
options
.
The
following
paragraphs
discuss the
use
of
these
controls
.
Stitsor
Rating
(
Prl
-
Amps
)
.
5
.
6
.
8
.
9
1.0
.
7
142.5
75
82.5 90
120
127.5
135
150 150
97.5
105
1125
170
180 190
200
100
110 120
130
140 150 160
200
300
150 165
240
255 270 285 150
180
195
210
225
400
200
220
240
320
340
360
380
400
260
280
300
540 570
600
300 330
510
600
360 390
420 450
480
680 720 760
800 400 440
520 560 640
800 480
600
1200
600
660 720 960
1020 1080
1140
1200
780
840 900
800 880
1360
1440 1520 1600 1600
960
1040
1120
1200
1280
2000
1000
1100
1700 1800 1900
2000
1200
1300
1400 1500
1600
1760 2720
2880
3040
3200 3200
1600
1920 2080 2240
2400
2560
4000
2000 2200 2400
2600
3200
3400 3600
3800
4000
2800
3000
Figure
8
.
Long
Time Element
Calibrated Current
Settings
NOTE
There is
a
plus
or
minus
10
%
tolerance
allowable
on
the
accuracy
of
the
trip
device
pickup
values
.
This
means
that
the
breaker
may
trip
for
currents
between
current
setting
and
plus
20
%
.
therefore
the
breaker
will
always
carry
current
setting
without
tripping
.
Figure
7
.
Static
Trip
III
RMS
-
TSIG
-
TZ
Device
INSTANTANEOUS
PICKUP
has
six
calibrated
points
.
2
X
.
4
X
.
6
X
.
8
X
,
12
X
and
15
X
calibrated
in
multiples
of
the
current
sen
-
sor
rating
.
The
instantaneous
setting
is
independent
of
the
long
time
current
setting
.
EXAMPLE
:
Referring
to
the
previous
example
,
suppose
it
is
desired that
the breaker
open
instantly
when
the
current
ex
-
ceeds
3200
amperes
.
3200
/
800
=
4
.
so
the
instantaneous
should
be
set
on
4
X
.
If
the
long
time
settings
are
changed
the
breaker
will
still
trip
at
3200
amperes
instantaneous
.
LONG
TIME
CURRENT
SETTING
has
11
calibrated
positions
.
These
are
marked
.
5
through
1.0
in
increments
of
.
05
.
Long
time
pickup
is
fixed
at
1.1
times the
long
time
current
setting
.
Figure
8
is
a
table
of
settings
in
primary
circuit
amperes
for
all
the
standard
current
setting
ratings
.
The
current
setting
rated
secondary
current
is
0.50
This
current
corresponds
to
long
time
current
setting
1
.
.
e
Courtesy of NationalSwitchgear.com

Operation
Page
10
(
V
TIME
CURVE
to
30
X
.
This
is
only
true
for
the
LOWEST
Long
Time
current
setting
With
the
Long
Time
current
setting
at
1.0
.
the
curves
extend
to
only
15
times
long
time
current
setting
.
This
is
the
maximum
primary
current
allowed
by
the
15
X
max
*
imum
pickup
setting
of
Instantaneous
.
SHORT
TIME
PICKUP
has
8
calibrated
settings
of
2
X
,
3
X
,
4
X
.
5
X
,
6
X
,
7
X
,
8
X
,
and
12
X
.
These
calibrated
values
are
in
multiples
of
the
LONG
TIME
current
setting
,
and
so
change
value
when
the
long
time
setting
is
adjusted
.
EXAMPLE
:
Refer
to
the
previous
example
,
suppose
that
it
is
desired
to
have
the
curves
transfer
from
the
long
time
curve
to
the
short
time
curve
for
currents
above
1800
amperes
.
1800
/
600
=
3
,
so
the
Short
time
pick
-
up
should
be
set
on
3
X
.
GROUND
PICKUP
has
five
calibrated
settings
of
20
%
,
30
%
.
40
%
,
50
%
and
60
%
,
as
shown
in
Figure
9
.
These
are
calibrated
as
multiples
of
the
ground
sensor
rating
.
For
cur
-
rent
sensors
through
2000
A
rating
,
the
ground
sensor
and
cur
-
rent
sensor
ratings
are
the
same
.
For
3200
A
and
4000
A
cur
-
rent
sensors
,
a
separate
2000
A
ground
sensor
winding
is
provided
.
EXAMPLE
:
In
our
example
the
ground
sensor
rating
is
800
amperes
,
so
for
a
Ground
pickup
setting
of
20
%
,
a
ground
cur
-
rent
exceeding
160
amperes
will
cause
the
ground
circuit
to
pickup
.
If
the
ground
current
persists
for
a
longer
time
than
the
setting
of
the
Ground
Fault
Delay
Band
setting
the
breaker
will
NOTE
The
NEC
does
not
allow
settings
above
1200
amperes
for
ground
fault
sensing
on
service
entrance
equip
-
ment
.
To
comply
special
ground
sensor
windings
with
2000
/
0.5
ratio
for
ground
sensing
are
provided
on
3200
A
and
4000
A
current
sensors
.
The
ground
sen
-
sor
rating
appears
on
the
sensor
rating
label
above
the
trip
unit
terminal
block
connection
.
(
trip
.
Sensor
Rating
Primary
Amps
As
explained
earlier
the
rated
secondary
current
for
the
sen
-
sors
is
0.5
ampere
,
so
the
20
%
setting
is
0.100
ampere
into
the
trip
device
ground
terminal
and
the
pickup
tolerance
is
±
10
%
of
this
value
.
20
%
60
%
50
%
30
%
40
%
75
90
150
60
30
45
200
100
120
80
40
60
300
60
150
180
90
120
200
240
400
80
1
?
0
160
300
240
360
600
120
180
Time
Bands
800
400
480
160
320
240
600
1200
240
360
720
480
There
are
five
LONG
TIME
DELAY
BANDS
available
on
all
Static
Trip
III
overcurrent
trip
devices
.
On
devices
with
Short
Time
there
are
five
SHORT
TIME
DELAY
BANDS
.
On
devices
with
GROUND
FAULT
tripping
there
are
three
time
delay
bands
for
the
ground
elements
.
On
Static
Trip
III
devices
with
both
Short
Time
and
Ground
,
the
Ground
circuits
are
prevented
from
tripping
if
the
Short
Time
pickup
currents
are
exceeded
.
Devices
with
Short
Time
have
a
switch
on
the
front
of
the
device
to
add
an
I
2
t
ramp
portion
to
the
time
delay
curve
for
Short
Time
.
These
curve
segments
can
be
selected
but
are
not
other
-
wise
adjustable
.
All
the
LONG
TIME
.
SHORT
TIME
INSTANTANEOUS
and
GROUND
FAULT
time
delay
bands
are
shown
on
the
TIME
-
CURRENT
CHARACTERISTICS
curve
Figure
3
.
The
curve
sheet
is
self
explanatory
,
except
for
the
extension
of
the
LONG
960
1600
320
640
800
480
1000
1200
800
2000
400
600
1000
3200
400
600
1200
800
1200
4000
400
1000
600
800
Figure
9
.
Ground
Element
Calibrated
Pickup
Settings
General
Notes
1
.
The
"
Current
Sensor
Rating
"
values
represent
the
primary
value
of
current
for
0.5
ampere
of
secondary
current
.
2
.
The
current
settings
are
switch
selectable
and
calibrated
at
points
.
5
through
1
0
as
shown
m
the
table
.
3
The
nominal
long
time
pickup
values
are
11
times
the
cur
-
rent
setting
with
a
tolerance
of
±
10
%
Courtesy of NationalSwitchgear.com

r
*
-
r
«
Operation
Page
11
f
*
w
4
.
The
pickup
settings
of
short
time
are
calibrated
at
2
.
3
.
4
.
5
.
6
.
7
,
8
.
and
12
times
the
long
time
current
setting
with
a
tolerance
of
+
20
%
-
0
.
5
.
The
Instantaneous
pickup
settings
are
at
2
.
4
.
6
.
8
.
12
and
15
times
the
current
sensor
rated
current
.
6
.
The
long
time
element
has
5
time
delay
bands
.
The
minimum
time
delays
at
6
X
current
setting
are
3.5
,
6
.
10
.
17
and
30
seconds
.
7
.
Short
time
has
5
time
delay
bands
.
8
.
Ground
elements
have
three
time
delay
bands
.
9
.
The
maximum
interrupting
time
is
the
maximum
length
of
time
that
fault
current
flows
,
including
arcing
time
.
10
.
Instantaneous
maximum
interrupting
time
may
be
greater
when
breakers
are
closed
in
on
a
fault
depending
on
ac
-
tual
fault
conditions
.
The
maximum
potential
increase
for
a
3
-
phase
fault
is
0.01
seconds
and
for
a
single
phase
ground
fault
is
0.02
seconds
.
The
Zl
coupler
connects
the
15
pm
sub
“
D
"
connection
on
the
trip
devices
to
an
external
terminal
block
mounted
in
the
breaker
cubicle
.
Zone
Interlock
Expander
The
Zone
Interlock
Expander
is
used
to
connect
the
Zl
output
signals
into
a
common
upstream
breaker
.
There
are
optical
isolators
inside
the
trip
device
that
depend
on
power
from
either
its
own
trip
device
,
or
from
the
one
that
it
is
connected
to
.
This
means
that
if
multiple
units
are
connected
in
parallel
,
the
trip
device
power
supplies
would
be
interconnected
.
A
fault
in
one
unit
could
then
disable
the
other
trip
devices
.
The
Zl
expander
overcomes
this
potential
problem
.
The
input
of
the
expander
consists
of
optical
isolators
with
their
outputs
connected
in
parallel
to
drive
the
Zl
input
of
the
upstream
device
.
It
derives
its
power
from
the
upstream
device
.
The
power
for
each
op
-
tical
isolator
input
is
supplied
from
its
own
downstream
trip
device
.
No
external
power
is
required
.
Load
Indicator
This
device
is
not
a
part
of
the
basic
overcurrent
protection
system
but
is
an
available
option
.
The
device
mounts
in
the
front
cover
of
the
circuit
breaker
and
its
input
cord
plugs
into
a
recep
-
tical
on
the
front
of
the
trip
device
as
shown
in
Figure
10
.
The
device
is
powered
by
the
trip
device
power
supply
and
con
-
tains
nine
LEDs
(
Light
Emitting
Diodes
)
that
are
illuminated
to
indicate
the
relative
magnitude
of
current
that
the
trip
device
senses
.
These
lights
indicate
current
in
multiples
of
device
pickup
value
.
The
first
light
is
illuminated
at
.
6
times
pickup
,
the
next
for
.
7
times
pickup
,
and
so
forth
,
up
to
1.4
times
pickup
.
In
addition
there
is
a
remote
overcurrent
alarm
“
contact
"
that
closes
when
the
current
equals
or
exceeds
the
value
selected
by
a
switch
on
the
front
of
the
Load
Indicator
.
The
switch
selects
any
of
the
indicated
current
values
,
from
.
6
to
1.4
times
Long
Time
Pickup
.
The
"
contact
"
is
an
optically
isolated
solid
state
switch
.
The
rating
of
the
arrangement
is
1
ampere
.
125
V
Nominal
.
AC
or
DC
.
These
“
contacts
"
are
wired
out
through
the
secondary
disconnects
of
the
breaker
.
Zone
Interlock
Coupler
This
device
is
not
part
of
the
basic
overcurrent
protective
system
but
is
used
to
connect
static
trip
devices
together
in
a
selective
Zone
Interlocking
(
Zl
)
System
.
The
Zl
coupler
provides
a
means
of
interconnecting
circuit
breakers
to
provide
closer
coordina
-
tion
for
the
SHORT
TIME
and
GROUND
FAULT
circuits
.
The
Zl
output
of
the
downstream
breaker
is
connected
to
the
Zl
in
-
nut
of
the
upstream
breaker
Figure
10
.
Optional
Load
Indicator
Device
Plugged
into
Static
Trip
III
Courtesy of NationalSwitchgear.com

Testing
Page
12
u
General
when
testing
with
the
device
on
the
breaker
.
Make
all
connec
-
tions
with
power
removed
from
the
test
set
.
When
testing
with
the
Static
Trip
III
device
off
the
circuit
breaker
,
connections
must
be
made
to
the
spade
type
terminals
of
the
connecting
strip
.
Making
these
connections
involves
the
risk
of
shorting
between
clips
which
can
damage
the
device
.
The
PTS
4
test
set
includes
a
terminal
block
for
the
connecting
strip
from
the
trip
device
similar
to
the
one
on
the
circuit
breaker
.
The
output
of
the
test
set
is
internally
connected
to
the
terminal
block
.
Static
Trip
III
trip
devices
can
be
field
tested
either
with
primary
current
through
the
breaker
or
with
secondary
current
applied
directly
to
the
trip
device
.
The
ease
of
testing
with
secondary
current
is
one
of
the
advantages
of
these
devices
.
With
com
-
paratively
inexpensive
and
readily
available
equipment
,
it
is
possible
to
demonstrate
that
the
tripping
system
will
open
the
breaker
and
verify
that
the
device
conforms
to
the
published
time
-
current
curves
.
However
,
field
testing
cannot
be
expected
to
be
as
accurate
as
factory
calibration
.
Therefore
slight
discrepancies
between
field
tests
and
factory
calibration
can
be
regarded
as
normal
.
If
large
deviations
or
improper
opera
-
tion
should
occur
,
it
is
recommended
that
your
Siemens
Energy
&
Automation
office
be
contacted
for
advice
Static
Trip
III
devices
have
two
LEDs
(
Light
Emitting
Diodes
)
mounted
on
the
front
panel
.
One
of
these
indicates
Long
Time
Pickup
and
the
other
indicates
Short
Time
or
Ground
Pickup
.
Unlike
the
earlier
model
of
trip
devices
no
connections
are
re
-
quired
to
indicate
when
pickup
occurs
.
These
LEDs
also
operate
during
normal
operation
on
the
breaker
,
and
are
useful
in
indicating
when
the
long
time
current
setting
may
be
set
too
Secondary
Current
Testing
low
.
Portable
test
set
PTS
4
is
available
for
secondary
current
testing
and
is
designed
to
plug
into
a
standard
120
volt
outlet
.
With
this
test
set
,
Static
Trip
III
trip
devices
can
be
tested
by
themselves
,
or
on
a
circuit
breaker
outside
the
cubicle
,
or
in
-
side
the
cubicle
with
the
breaker
in
the
TEST
or
DISCON
-
NECTED
position
.
Figure
11
shows
the
PTS
4
test
set
.
Test
Connections
<
3
Current
is
supplied
to
terminals
1
and
5
to
test
phase
1.2
and
5
to
test
phase
2
,
3
aqd
5
to
test
phase
^
,
4
and
5
to
test
the
ground
circuit
on
devices
with
ground
fault
tripping
.
For
secondary
current
testing
a
circuit
breaker
is
not
needed
.
If
the
device
is
mounted
on
a
circuit
breaker
it
is
not
necessary
to
close
the
breaker
.
Long
Time
Pickup
Test
Set
the
LONG
TIME
CURRENT
SETTING
on
.
5
.
Move
the
switch
above
the
LED
timer
readout
on
the
PTS
4
to
“
Static
Trip
III
Long
Time
.
"
Raise
the
current
slowly
until
the
long
time
pickup
LED
is
illuminated
.
This
should
occur
at
.
275
amperes
,
within
the
±
10
percent
tolerance
band
.
Decrease
the
current
slightly
and
the
LED
should
go
out
.
When
the
LED
is
illuminated
continuously
the
device
will
eventually
time
out
.
If
the
Thermal
Memory
switch
is
“
In
"
the
device
will
eventually
time
out
when
the
LED
is
illuminated
approximately
50
%
of
the
time
.
The
LONG
TIME
circuits
calculate
the
true
RMS
value
.
This
pro
-
duces
a
noticeable
time
delay
from
the
time
the
current
reaches
the
pickup
point
to
the
time
pickup
is
indicated
by
the
LED
.
Repeat
the
test
for
the
other
available
settings
and
compare
to
the
values
in
Table
4
.
Figure
11
.
Portable
Test
Set
PTS
4
i
The
illumination
on
the
pickup
LED
indicates
that
the
time
delay
has
started
The
timing
circuit
does
not
have
the
time
lag
evi
-
dent
in
the
pickup
indication
When
the
“
Thermal
Memory
There
is
a
terminal
block
on
the
circuit
breaker
just
above
the
trip
device
This
terminal
block
accepts
a
plug
from
the
test
set
Courtesy of NationalSwitchgear.com

Testing
Page
13
switch
is
"
Out
.
’
*
the
LONG
TIME
elements
will
be
cleared
each
time
the
LED
goes
out
;
if
the
‘
Thermal
Memory
’
’
switch
is
“
In
.
”
the
device
will
accumulate
the
overload
times
and
will
treat
a
series
of
short
overloads
as
if
it
were
one
interval
.
While
the
overload
is
below
the
current
setting
the
time
register
slowly
resets
,
so
that
if
the
periods
between
overloads
are
long
enough
the
device
will
not
trip
.
Instantaneous
is
calibrated
in
multiples
of
0.5
ampere
.
Unlike
the
SHORT
TIME
PICKUP
it
is
not
effected
by
the
current
set
-
ting
of
the
LONG
TIME
element
.
NOTE
Short
Time
Pickup
Test
Do
not
allow
currents
above
one
ampere
to
flow
for
more
than
a
minute
,
to
avoid
overheating
the
trip
device
.
A
circuit
breaker
is
provided
in
the
PT
$
4
test
set
to
prevent
thermal
damage
from
repeated
high
current
tests
.
At
higher
settings
some
of
the
other
cir
-
cuits
may
time
out
while
the
current
is
being
raised
to
the
instantaneous
level
.
This
can
be
minimized
by
setting
the
LONG
TIME
CURRENT
and
DELAY
and
SHORT
TIME
PICKUP
on
their
maximum
settings
.
Set
LONG
TIME
CURRENT
SETTING
on
.
5
and
SHORT
TIME
PICKUP
on
2
X
.
Raise
the
current
slowly
until
the
Short
Time
/
Ground
Pickup
LED
is
illuminated
.
This
should
be
at
.
55
amperes
as
shown
in
Table
1
.
Repeat
for
other
SHORT
TIME
settings
as
desired
On
devices
with
Targets
the
SHORT
CIRCUIT
targets
should
operate
when
the
device
operates
on
its
IN
-
STANTANEOUS
or
SHORT
TIME
element
.
NOTE
Do
not
allow
currents
above
one
ampere
to
continue
for
more
than
a
minute
at
a
time
to
avoid
overheating
the
trip
device
.
A
circuit
breaker
is
provided
in
the
PTS
4
test
set
to
prevent
thermal
damage
from
repeated
high
current
tests
.
Select
the
phase
to
be
tested
.
Set
the
INSTANTANEOUS
on
2
X
,
increase
the
current
slowly
until
the
breaker
trips
and
/
or
the
PTS
4
test
set
timer
stops
.
This
should
occur
at
1.0
ampere
.
Test
the
other
pickup
settings
as
desired
.
See
Table
2
for
calibrated
pickup
values
.
Table
2
Instantaneous
Secondary
Pickup
Currents
Table
1
Short
Time
Secondary
Pickup
Currents
(
Long
Time
Current
Setting
on
.
5
)
Instantaneous
Pickup
Short
Time
Pickup
12
X
15
X
8
X
4
X
6
X
2
X
3
X
4
X
5
X
6
X
7
X
8
X
12
X
2
X
Secondary
Amperes
Secondary
Amperes
7.5
1.925
2.2
60
3.3
4.0
2.0
3.0
1.375
1.65
1.0
0.55
.
825
1.1
Ground
Pickup
Test
Instantaneous
Trip
Test
Select
Static
Trip
III
ground
test
on
the
PTS
4
Observe
the
Short
Time
/
Ground
Pickup
LED
.
This
is
the
same
LED
that
indicates
SHORT
TIME
pickup
The
ground
settings
are
as
shown
in
Table
3
.
Pickup
for
the
INSTANTANEOUS
element
is
demonstrated
by
tripping
of
the
circuit
breaker
or
operation
of
the
targets
and
relay
m
the
portable
test
set
Courtesy of NationalSwitchgear.com

Testing
Page
14
(
-
Thermal
Memory
Test
Table
3
Ground
Fault
Secondary
Pickup
Currents
The
“
Thermal
Memory
”
function
accumulates
the
LONG
TIME
signal
and
provides
a
cool
down
function
for
the
LONG
TIME
delay
.
Switching
the
thermal
memory
“
Out
”
disables
the
in
-
tegrator
and
allows
the
long
time
delay
elements
to
reset
when
ever
the
long
time
signal
drops
below
pickup
.
When
the
“
Ther
-
mal
Memory
”
switch
is
“
In
"
the
long
time
delay
elements
are
not
reset
when
the
signal
drops
below
pickup
,
but
are
decreas
-
ed
slowly
with
time
.
Ground
Fault
Pickup
50
%
40
%
50
%
30
%
20
%
Secondary
Amperes
0.3
0.25
0.15
0.2
0.1
Due
to
the
low
values
of
current
the
trip
device
may
not
trip
the
circuit
breaker
when
tested
with
secondary
current
into
the
ground
circuit
only
.
It
may
be
necessary
to
supply
some
phase
current
in
order
to
have
sufficient
power
to
release
the
tripping
actuator
.
To
check
the
operation
of
the
circuit
,
set
LONG
TIME
CUR
-
RENT
SETTING
on
.
5
,
LONG
TIME
DELAY
BAND
on
3.5
and
move
the
“
Thermal
Memory
"
switch
to
“
In
.
"
Make
sure
the
switch
above
the
LED
timer
readout
on
the
PTS
4
is
set
to
“
Static
Trip
III
Long
Time
.
"
Apply
.
55
amperes
to
one
phase
input
and
allow
the
device
to
time
out
.
Record
the
time
.
Move
the
“
Thermal
Memory
"
switch
to
“
Out
,
"
repeat
the
same
test
and
record
the
time
.
It
should
be
the
same
as
the
first
test
.
Long
Time
Delay
Test
Use
the
high
range
ammeter
setting
on
the
PTS
4
test
set
.
Now
move
the
“
Thermal
Memory
“
switch
back
to
“
In
.
"
Repeat
the
test
,
but
this
time
momentarily
lower
the
current
every
10
seconds
to
0.2
ampere
for
approximately
3
seconds
until
the
long
time
pickup
LED
goes
out
.
Be
very
careful
to
not
drop
below
0.15
amperes
.
Again
,
measure
and
record
tripping
time
.
This
should
be
approximately
the
same
as
for
the
first
two
tests
.
Move
the
“
Thermal
Memory
”
switch
to
the
“
Out
”
position
and
repeat
this
test
.
In
this
case
the
device
should
never
time
out
and
it
should
be
possible
to
continue
the
cycle
indefinitely
.
1
.
Move
the
switch
above
the
timer
LED
readout
on
the
PTS
4
to
“
Static
Trip
III
Long
Time
"
2
.
Close
the
switch
and
set
the
current
to
the
desired
value
.
3
.
Open
the
switch
and
close
the
circuit
breaker
.
4
.
Without
changing
the
setting
of
the
current
source
,
close
the
switch
and
measure
the
time
until
the
breaker
opens
.
Com
-
pare
the
results
to
the
time
current
curves
of
Figure
3
.
Example
:
Set
LONG
TIME
CURRENT
SETTING
on
.
5
,
LONG
TIME
BAND
on
17
,
Input
current
at
1.65
amperes
(
6
Times
.
25
x
1.1
)
.
Set
SHORT
TIME
and
INSTANTANEOUS
on
12
X
.
The
timed
interval
should
be
between
17
and
25
seconds
.
On
models
with
targets
the
OVERLOAD
target
should
indicate
when
tripping
occurs
.
Short
Time
Delay
Test
To
test
,
set
INSTANTANEOUS
to
its
maximum
,
and
move
the
small
selector
switch
labeled
SHORT
TIME
I
2
t
to
“
Out
.
”
Set
LONG
TIME
CURRENT
SETTING
on
.
5
.
SHORT
TIME
PICKUP
on
2
X
,
set
the
PTS
4
test
set
current
source
for
2
to
3
amperes
,
close
the
breaker
and
apply
the
current
The
breaker
should
trip
within
the
limits
of
the
SHORT
TIME
BAND
selected
.
NOTE
On
models
with
Targets
the
SHORT
CIRCUIT
target
should
operate
.
On
models
with
ZONE
INTERLOCKING
the
time
delay
will
be
approximately
0.1
second
with
the
Zone
Interlock
switch
While
timing
out
at
values
slightly
above
pick
-
up
with
the
“
Thermal
Memory
”
switch
“
Out
,
”
normal
varia
-
tions
in
supply
voltage
may
cause
the
device
to
drop
out
momentarily
and
cause
the
timing
to
be
inter
-
rupted
.
It
is
recommended
that
the
pickup
LED
be
monitored
throughout
the
test
.
Also
,
for
the
same
reason
,
attempting
to
test
LONG
TIME
timing
at
less
than
20
percent
above
the
current
setting
may
not
be
successful
In
.
”
The
operation
of
the
SHORT
TIME
I
2
t
ramp
can
be
checked
by
supplying
1.5
amperes
to
the
device
.
Repeat
the
test
to
measure
the
time
delay
.
Move
the
SHORT
TIME
I
2
t
ramp
switch
to
the
“
In
'
'
position
,
and
repeat
the
test
at
the
same
current
.
The
delay
should
be
longer
with
the
switch
“
In
.
”
4
Courtesy of NationalSwitchgear.com

Testing
Page
15
Ground
Time
Delay
Test
The
GROUND
time
delay
can
be
tested
similar
to
the
SHORT
TIME
delay
test
When
the
tripping
output
appears
,
the
GROUND
FAULT
target
appears
.
as
described
previously
.
Then
at
the
15
pm
connector
,
con
-
nect
pin
5
to
pin
4
and
pin
6
to
pm
1
or
2
and
repeat
the
timing
tests
.
The
time
delay
should
then
change
to
the
selected
band
.
If
the
short
time
I
2
t
switch
is
"
In
.
”
the
incoming
Zt
signal
will
not
change
the
time
delay
unless
the
current
used
in
the
test
is
above
the
range
where
the
I
2
t
ramp
circuits
affect
the
delay
.
The
nominal
current
values
for
secondary
testing
of
Static
Trip
III
long
time
function
are
given
in
Table
4
below
.
Zone
Interlock
Test
On
devices
with
the
Zone
Interlock
option
,
both
the
SHORT
TIME
and
the
GROUND
time
delay
bands
are
affected
by
the
incoming
Zl
signal
.
With
no
incoming
Zl
signal
both
time
delay
bands
will
be
on
their
minimum
.
When
an
incoming
Zl
signal
is
present
both
the
SHORT
TIME
and
GROUND
delay
elements
operate
on
the
band
selected
by
the
front
panel
controls
.
On
devices
containing
the
Zl
function
,
the
Zl
output
circuit
pro
-
vides
an
output
signal
anytime
either
the
SHORT
TIME
or
GROUND
pickup
values
are
exceeded
.
Both
the
incoming
and
outgoing
Zl
circuits
are
isolated
by
an
optical
isolator
inside
the
device
,
so
some
power
must
be
pro
-
vided
to
the
trip
devices
,
as
in
normal
operation
.
Both
sets
of
signals
are
brought
out
the
15
pin
connector
.
Ter
-
minal
numbering
is
from
1
through
15
.
Pin
1
and
2
are
the
device
negative
power
.
Pin
3
is
the
device
+
12
volt
power
.
Pin
4
is
the
+
5
volts
from
the
target
power
supply
.
Pm
5
is
the
Zl
positive
signal
input
.
Pin
6
is
the
Zl
negative
signal
input
.
Pin
7
is
the
Zl
negative
signal
output
.
Pin
8
is
the
Zl
positive
signal
output
.
The
signals
from
the
15
pm
connector
are
connected
together
into
a
Zone
Interlocking
System
through
a
Zone
Interlock
Coupler
and
/
or
Zone
Interlock
Expander
mounted
in
the
breaker
cubicle
The
Zl
output
is
an
isolated
transistor
that
can
be
checked
with
an
ohmmeter
,
or
by
using
a
dropping
resistor
and
connecting
up
both
the
device
’
s
positive
and
negative
power
supply
and
detecting
turn
on
of
the
transistor
with
a
voltmeter
.
This
tran
-
sistor
turns
ON
when
either
SHORT
TIME
or
GROUND
elements
have
picked
-
up
A
Resistor
of
approximately
220
ohms
should
be
used
to
limit
the
current
through
the
transistor
during
testing
.
Connect
the
resistor
from
pm
3
to
pm
8
,
connect
pm
7
to
pm
1
or
2
.
Measure
the
voltage
between
pins
7
and
8
.
To
check
the
operation
of
the
Zl
input
circuit
,
set
the
SHORT
TIME
and
GROUND
time
delay
bands
above
minimum
band
so
that
a
difference
m
timing
can
be
detected
.
Move
the
SHORT
TIME
l
2
t
switch
to
the
“
out
"
posilion
Run
(
he
time
delay
test
Table
4
Secondary
Pickup
Current
Current
Setting
.
5
1.0
.
9
.
7
.
8
.
6
Secondary
Current
.
30
.
33
.
358
.
385
.
413
.
44
.
468
.
495
.
523
.
55
.
275
Load
Indicator
Output
Test
All
Static
Trip
III
trip
devices
have
a
nine
pin
connector
on
the
front
of
the
device
to
connect
to
the
load
indicator
unit
.
If
the
load
indicator
is
available
it
can
be
used
to
test
the
output
signals
.
If
there
is
a
malfunction
between
the
two
assemblies
,
substitution
of
either
unit
is
the
best
field
test
to
isolate
the
defec
-
tive
assembly
.
The
output
signal
is
a
four
bit
,
latched
,
parallel
binary
word
representing
the
calculated
RMS
current
in
the
highest
phase
.
This
is
provided
to
the
load
indicator
on
pins
2
through
5
of
the
nine
pin
connector
,
with
the
following
code
:
Current
,
in
Multiples
of
Long
Time
Pickup
Value
Binary
Word
0001
0.6
X
0010
Q
.
7
X
0011
0.8
X
0100
0.9
X
1
,
0
X
(
this
is
long
time
pickup
current
)
1.1
X
1.2
X
0101
0110
0111
1000
1.3
X
1001
1.4
X
The
connector
also
contains
+
5
volts
on
pin
1
to
power
the
load
indicator
.
The
negative
or
common
line
is
on
pm
9
Courtesy of NationalSwitchgear.com

Testing
Page
16
Do
not
disassemble
the
tripping
actuator
,
this
may
partially
demagnetize
it
,
and
remagnetizing
requires
special
equipment
.
Pin
8
is
a
signal
called
NOT
RESET
.
This
signal
is
used
to
enable
the
load
indicator
and
is
+
5
volts
DC
when
current
supplied
to
the
trip
device
is
above
approximately
100
milliamperes
.
Below
this
input
level
none
of
the
data
is
accepted
.
All
pins
can
be
checked
with
a
voltmeter
while
current
is
adjusted
as
desired
.
Flickering
of
the
LED
output
is
normal
.
The
load
indicator
assembly
decodes
the
number
and
drives
a
light
emitting
diode
bar
display
to
indicate
the
magnitude
of
current
.
The
indicator
also
contains
an
alarm
setting
switch
and
circuitry
that
selects
any
one
of
the
current
levels
indicated
and
closes
a
solid
state
alarm
contact
when
that
level
is
exceeded
.
The
solid
state
contact
is
rated
1
ampere
.
125
V
nominal
DC
or
AC
.
Current
Sensor
Test
The
tests
described
in
the
preceding
verify
performance
of
the
trip
device
and
tripping
actuator
.
The
third
link
in
the
Static
Trip
III
protection
system
is
the
breaker
mounted
current
sensors
.
These
are
special
purpose
current
transformers
.
When
secondary
current
testing
is
done
with
the
trip
device
on
the
breaker
,
the
current
sensors
are
subjected
to
approximately
their
normal
excitation
so
that
a
transformer
with
shorted
turns
may
show
up
in
the
form
of
pickup
values
above
tolerance
.
However
,
further
testing
is
required
to
tell
if
the
problem
is
in
the
static
trip
device
or
in
the
sensors
.
Moreover
,
an
open
circuit
in
the
transformer
winding
or
wiring
would
not
show
up
at
all
.
Therefore
,
it
is
desirable
to
test
the
current
sensors
as
described
in
the
following
.
Tripping
Actuator
Test
If
the
trip
device
fails
to
trip
the
breaker
,
the
question
arises
as
to
whether
the
trouble
is
in
the
trip
device
or
in
the
actuator
.
Substitution
of
a
known
good
trip
device
is
an
easy
way
to
supp
-
(
_
ly
a
quick
answer
.
If
another
trip
device
is
not
available
the
actuator
can
be
tested
by
applying
voltage
to
its
trip
winding
with
the
PTS
4
test
set
.
This
winding
connects
to
the
terminal
block
with
the
positive
terminal
on
number
7
and
the
negative
terminal
on
number
6
.
The
leads
of
the
actuator
are
also
color
coded
,
red
is
positive
,
black
is
negative
,
and
blue
is
the
hold
-
in
winding
.
With
the
breaker
dosed
,
apply
DC
voltage
to
the
terminals
for
the
trip
winding
,
start
at
zero
voltage
and
slowly
increase
until
the
actuator
trips
.
The
voltage
should
be
between
3
and
6
volts
.
Should
the
actuator
fail
to
trip
check
the
coil
resistance
.
It
should
be
between
15
and
25
ohms
.
Double
check
the
polarity
of
the
test
voltage
and
check
for
any
mechanical
interference
in
or
around
the
actuator
.
Connections
If
the
trip
device
is
on
the
breaker
,
disconnect
it
by
removing
the
connector
strip
from
the
lower
row
of
terminal
block
con
-
nections
.
The
current
sensors
can
now
be
tested
by
making
connections
to
the
banana
jacks
on
the
top
row
of
terminal
block
connections
.
Continuity
Checks
An
ohmmeter
is
most
suitable
for
checking
the
continuity
of
the
sensor
secondary
windings
and
wiring
.
Connect
the
ohmmeter
from
terminal
1
to
terminal
5
for
Phase
1
.
from
terminal
2
to
terminal
5
for
Phase
2
.
from
terminal
3
to
terminal
5
for
Phase
3
.
The
exact
value
of
resistance
is
not
important
so
long
as
there
is
continuity
.
The
resistance
should
be
approximately
the
same
for
all
phases
on
a
given
breaker
,
but
can
vary
widely
for
the
various
ratios
of
the
sensors
available
.
^
Caution
When
ground
protection
is
provided
,
the
ground
strap
or
neutral
sensor
,
whichever
is
used
,
is
mounted
external
to
the
circuit
breaker
and
is
wired
to
the
trip
device
through
the
breaker
secondary
disconnects
on
the
side
of
the
breaker
.
To
check
this
circuit
the
breaker
must
be
in
the
TEST
position
.
Then
the
ohmmeter
check
can
be
made
between
terminal
4
and
terminal
5
of
the
trip
device
terminal
block
The
circuit
breaker
wiring
diagram
should
be
checked
for
any
special
connections
that
may
have
been
made
.
USE
EXTREME
CAUTION
WHEN
WORK
-
ING
ON
CIRCUIT
BREAKERS
.
THE
ENERGY
STORED
IN
THE
CLOSING
AND
OPENING
SPRINGS
MUST
BE
RESPECTED
.
ALWAYS
DISCHARGE
ALL
SPRINGS
BEFORE
PLACING
HANDS
NEAR
THE
MECHANISM
.
See
the
circuit
breaker
instruction
manual
if
there
is
any
pro
-
blem
evident
in
the
mechanical
portion
4
Courtesy of NationalSwitchgear.com

Testing
Page
17
*
For
the
lower
ratios
the
continuity
check
can
be
omitted
since
the
indicated
magnetizing
current
would
verify
continuity
.
Excitation
Test
The
purpose
of
the
excitation
test
is
to
reveal
shorted
turns
in
the
current
sensor
winding
.
Sixty
(
or
50
)
Hertz
AC
voltage
is
applied
to
the
secondary
winding
and
the
exciting
current
is
monitored
.
Short
circuited
turns
will
be
revealed
by
excessive
exciting
current
and
possibly
by
overheating
of
the
winding
.
A
120
V
variable
transformer
(
Variac
)
and
a
low
range
ammeter
is
all
that
is
required
,
although
a
0
-
150
Volt
AC
voltmeter
is
desirable
to
monitor
the
applied
voltage
.
The
ammeter
in
the
PTS
4
test
set
can
be
used
by
passing
current
through
the
ex
-
ternal
current
input
.
In
the
absence
of
a
voltmeter
the
dial
reading
on
the
variable
transformer
can
be
used
as
an
approximate
voltage
indicator
.
See
Table
5
.
Sensor
Polarity
For
the
ground
fault
detection
elements
to
operate
properly
the
sensors
must
be
connected
with
the
proper
polarity
.
The
polarity
of
any
given
sensor
can
be
checked
by
'
flashing
”
the
primary
with
a
short
duration
pulse
of
known
DC
polarity
and
observ
-
ing
the
polarity
of
the
induced
secondary
voltage
on
make
and
break
of
the
primary
.
A
6
volt
dry
cell
can
be
used
for
the
primary
source
and
the
polarity
indicated
by
a
DC
voltmeter
connected
to
the
secondary
winding
.
Refer
to
the
three
line
diagram
for
the
correct
neutral
or
ground
return
sensor
polarity
.
Primary
Current
Testing
Table
5
Current
Sensor
Exciting
Current
Test
Testing
with
primary
current
applied
to
the
circuit
breaker
re
-
quires
a
low
voltage
high
current
supply
that
can
deliver
cur
-
rents
up
to
4
or
6
times
the
sensor
rated
current
.
There
is
com
-
mercially
available
equipment
made
for
this
purpose
.
This
equipment
generally
includes
the
ammeters
and
timers
need
-
ed
to
fully
test
the
breaker
.
Primary
current
testing
can
provide
the
ultimate
in
assurance
that
the
entire
protective
system
is
functioning
properly
,
since
the
entire
system
is
tested
at
one
time
.
However
,
primary
cur
-
rent
testing
may
present
additional
problems
.
One
major
dif
-
ficulty
arises
from
the
non
-
linear
impedance
of
the
trip
device
power
supply
circuit
.
This
circuit
is
designed
to
provide
power
to
operate
at
low
levels
of
current
,
then
change
impedance
for
higher
levels
of
current
to
protect
the
trip
device
.
When
sup
-
plied
from
a
low
voltage
source
this
changing
impedance
alters
me
waveshape
of
the
current
supplied
to
the
trip
device
.
This
can
result
in
insufficient
power
to
properly
operate
the
trip
device
,
or
it
may
affect
the
indication
of
the
source
ammeter
,
depending
on
the
ammeter
design
,
leading
to
the
erronious
assumption
that
the
trip
device
calibration
is
incorrect
.
One
other
major
difficulty
with
primary
current
testing
is
related
to
the
duty
cycle
limitation
of
the
circuit
breaker
and
current
sensors
.
A
properly
operating
tripping
system
will
be
self
-
protecting
from
thermal
damage
up
to
the
circuit
breaker
short
time
and
interruption
rating
,
providing
that
the
duty
cycle
ap
-
plicable
for
each
rating
is
not
exceeded
.
The
standard
duty
cy
-
cle
for
the
short
time
rating
as
demonstrated
per
ANSI
C
37.50
is
0.5
Seconds
ON
.
15
Seconds
OFF
followed
by
a
second
ON
period
of
0.5
Second
.
The
ON
intervals
are
too
short
to
read
the
ammeter
on
the
current
source
.
For
the
instantaneous
interruption
rating
each
of
the
ON
intervals
are
reduced
to
ap
-
proximately
50
Milliseconds
.
Because
of
this
,
calibration
of
the
Maximum
Exciting
Current
120
Volt
Variac
Setting
t
Sensor
Rating
Applied
Volts
33.5
0.25
150
25
0.15
200
67
50
0.10
300
50
67
0.10
400
50
67
0.05
600
50
67
134
0.03
800
100
0.02
1200
&
Up
134
100
Again
each
phase
must
be
tested
in
turn
and
the
trip
device
must
be
disconnected
.
Connect
the
AC
supply
to
terminals
1
and
5
for
Phase
1
.
terminals
2
and
5
for
Phase
2
and
from
ter
-
minals
3
and
5
for
Phase
3
.
The
output
selector
switch
can
be
used
to
select
each
phase
when
the
PTS
4
test
set
is
used
.
To
test
the
Ground
strap
or
neutral
sensor
it
is
necessary
to
have
the
breaker
in
the
cubicle
,
in
the
TEST
position
.
Again
check
the
breaker
wiring
diagram
,
for
any
special
connections
that
may
have
been
made
.
Table
5
gives
the
applied
voltage
and
test
limits
of
exciting
cur
-
rent
for
all
standard
current
sensor
ratings
.
The
value
of
.
02
ampere
is
about
the
lowest
readable
current
using
the
ammeters
in
the
PTS
4
portable
test
sets
,
and
the
sen
-
sors
that
meet
this
limit
will
give
satisfactory
performance
.
Nor
-
mal
exciting
currents
for
sensors
rated
400
amperes
and
above
may
be
well
below
this
value
Therefore
when
checking
high
rating
sensors
it
is
essential
to
perform
the
continuity
check
Courtesy of NationalSwitchgear.com