Siemens Static Trip III User Manual

lnstallation
and
Adjustments
lnstructions
Y
v
On trip units with
both
ShortTime and
Ground Fault Protection,
the
ground
fault
tripping is inhibited
if
the trip unit is executing
the short
time fault
protection
sequence.
Ground Fault Pickup
The
ground
fault
pickup
sets the level
of
ground
current
at
which
the circuit interruption
sequence is initiated.
Together
with
the
ground
fault
delay, this setting
allows selective
tripping
between main
and feeder
or other
downstream circuit
break-
ers, The
ground
fault
pickup
may be set
to
20,
30, 40, 50
or,
60% of the
ground
sensor rating. The
tolerance
on the
ground
fault
pickup
is
plus
or minus
10%.
Note
that the
ground
fault
pickup
adjustment
references
the
"Ground
Sensor Rating."
This
gives
simple referencing
re-
gardless
of the type
of
ground
fault
scheme
used. Further-
more,
it allows
trip units
to be lnterchanged
between
circuit
breaker frames
of all ratings
and between
different
ground
fault
schemes.
The
ground
sensor rating
appears
on the circuit
breaker rating
label
above the trip
unit for residual
ground
fault
sensing schemes,
or
on the right side
of the circuit
breaker
cubicle for
direct
source or zero
sequence type
schemes, See
the
ground
fault
sensing diagrams for
additional information.
Ground Fault
Protection
Ground Fault
Frekup
Delay
50
SC
,10
,,1
^
:5
:n
30
)(\
',n
Grd Serrsor
Direct
Source or Zero
Sequence Ground Fault
Schemes
10
Ground Current in Percent
of
Ground Sensor
Rating
EA
JU 100
10
50
o
!,
o
o
o
a
'.
E
tr
I
Ground
fault
pickup
set at
50%.
Pickup wi
I be
between 45 and
Atro/- nf nrnr rnrl
sensor ratrng.
I
Example
-
Ground Fault P
ckup
IY
Res
dua Ground Fault
Schemes
l5

Siemens Static Trip III Specifications

General

Brand	Siemens
Model	Static Trip III
Category	Circuit breakers
Language	English