GE AKR - Page 21

1
Trip
Devices
Continued
High
Range
Instantaneous
Includes
adjustable
short
-
short
-
time
rating
permitting
maximum
use
of
the
time
pickup
,
adjustable
short
-
time
delay
and
a
high
-
breaker
'
s
short
-
time
capa
-
level
instantaneous
setting
is
adjustable
in
four
steps
from
40
to
100
percent
of
the
circuit
breaker
frame
bility
.
This
high
level
instan
-
taneous
function
increases
system
protection
without
losing
selectivity
.
The
ground
fault
delay
adjustment
is
used
to
add
a
pre
-
determined
delay
in
time
to
the
trip
point
once
the
ground
fault
pickup
level
has
been
reached
.
This
provides
tripping
selectivity
between
main
and
feeder
or
other
downstream
breakers
.
The
ground
fault
unit
also
includes
as
standard
an
inverse
l
2
t
ramp
to
substan
-
tially
improve
coordination
with
downstream
protective
devices
such
as
fuses
and
thermal
magnetic
circuit
breakers
.
Ground
Fault
Pickup
and
Ground
Fault
Delay
(
Optional
)
The
ground
fault
pickup
adjustment
controls
the
level
of
ground
fault
current
at
which
circuit
interruption
will
occur
.
To
comply
with
the
1981
National
Electrical
Code
(
NEC
230
-
95
)
,
no
trip
point
exceeds
1200
amperes
.
The
common
square
knee
of
the
curve
can
be
replaced
with
an
l
2
t
function
to
facilitate
coordi
-
nation
with
downstream
devices
such
as
thermal
-
magnetic
breakers
and
fuses
whose
time
-
current
curves
do
not
easily
relate
to
the
square
-
shape
sensing
characteristics
common
to
solid
state
trip
devices
.
<
GROUND
FAULT
PICKUP
3
S
35
S
GROUND
FAULT
PICKUP
ZZZZZZZZ
2
V
,
GROUND
FAULT
DELAY
l
2
T
IN
12
T
OUT
MAX
MAX
v
'
\
1
«
!
,
A
\
A
4
GROUND
FAULT
DELAY
^
4
*
N
-
.
diagrams
,
it
can
be
seen
how
the
memory
function
works
.
Diagram
A
shows
a
typical
ground
fault
with
half
-
cycles
,
whole
cycles
and
multiple
cycles
missing
,
as
normally
occurs
.
Diagram
B
shows
trip
response
of
atypical
ground
fault
function
which
does
not
include
memory
.
The
breaker
never
trips
because
the
time
delay
circuits
are
reset
with
every
missing
cycle
.
Diagram
C
shows
response
of
MicroVersaTrip
ground
fault
circuits
to
the
same
ground
fault
;
the
circuit
’
s
memory
carries
through
the
missing
cycles
and
gener
-
'
G
/
ates
a
trip
signal
after
the
preset
time
delay
.
Memory
Circuit
Because
of
the
highly
inter
-
mittent
and
erratic
nature
of
arcing
ground
faults
,
a
mem
-
ory
circuit
has
been
incorpo
-
rated
in
all
MicroVersaTrip
ground
fault
sensing
circuits
as
standard
.
The
memory
circuit
integrates
arcing
fault
current
with
time
,
essentially
summing
the
intermittent
ground
current
spikes
.
In
the
Ground
Fault
Tr
<
p
Line
/
1
A
/
.
A
A
(
D
t
Ground
Fault
Wrihoui
Memory
me
Ground
Fault
Response
With
Memory
\
Courtesy of store.ips.us