Flux Shift Trip Device - GE AKR Series Maintenance Manual Supplement

GEI-86134, Power Circuit Breqkers
I BREAKER
\
\
CLOSED
POSITION
/
ACTUATOR
Fig.
22.
Flux shi.ft
trip
deuice and
operating
li.nkages
FLUX
SHIFT
TRIP
DEVICE
The mounting arrangement of
this
component
is
illustrated in
Figs.
22
and23.
An electromagnetic
actuator located
on
the undersideof
the
front frame
is
coupled
to the breaker's
trip
shaft via
a
trip
rod
driven
by the
actuator
arm.
The
acfuator
is
a
solenoid whose armature
is
spring-loaded
and
held
in its normal
(Reset)
position by
a
permanent mag-
net.
In this state the spring
is
compressed.
So
long as
the acfuator remains inthe Reset po-
sition,
the
breaker
can be closed
and opened
norm-
ally
at
will.
However, when a closed breaker
re-
ceives a
bip
signal from the programmer unit,
the
actuator
is
energized and
its
solenoid
flux
opposes
the magnet, allowing the spring
to
release the arm-
ature; this drives the
trip
rod
against the
trip
shaft
paddle, tripping the breaker.
As the breaker opens, the actuator arm is re-
turned
to its
normal (Reset)
position via
linkage
driven by a crank on thebreaker's main sha-ft.
The
permanent magnet again holds
the
armature captive
in readiness
for
the next
trip
signal.
The
trip
device requires only
one adjustment
-
thetrip
rod length. As
shown
in
Fig. 24,
the
clear-
ance between
the
trip
rod
end and the
trip
shaft
paddle
is
gaged by a 0.125 inch diameter
rod.
Ad-
20
just
gap to
0. 125 inch+
0.
015
inch.
To adjust,
open
the
breaker
and
restore
the
breaker mechanism
to
its
Reset
position.
Loosen the
jam nut, rotate
the
adjuster
end
until
the
proper gap is
attained,
then
retighten the jam
nut.
The actuator
is
a
sealed, factory-set device
and
requires no
maintenance
or field
adjustment.
In
case
of
malfunction,
the
complete actuator unit
should
be
replaced.
When
making
the electrical
connection
to
the replacement
unit,
it
is
recom-
mended that the breaker harness be cut at
some
convenient
point
and
the new
actuator leads solder-
spliced
thereto.
An afternate methodis to untie
the
breaker harness
and
remove
the
old
actuator leads
directly from
the
female AMP connector
on
the
end
of
the
breaker
harness.
However. AMP extraction
tool Cat. No.
305183
is
required
for
this
method.
CAUTION:
IN
THE EVENT
TIIAT
THE
SST TRIP DEVICE
MUST
BE RENDERED
INOPERATIVE
TO ALLOW
THE
BREAKER TO CARRY CURNENT WITH-
OUT BENEFIT OF OVERCURRENT PRO-
TECTION, THE
RECOMMENDED
METHOD
/S
TO
SHORTEN
THE
TRIP
ROD
BY
TURNING ITS ADJUSTEN
END
FULLY
CLOCKWISE. THIS
PREVENTS
ACTUATION
OF THE
TRIP
SHAFT
PADDLE,