Flux Shift Trip Device - GE AKR-4-30 Maintenance Manual Supplement

GEI-86134, Power Circuit Breakers
CRANK
(
BREAKER
CLOSED POS I T I ON
TRIP
PADDLE

FLUX SHIFT TRIP DEVICE

The mounting arrangement of this component is
22
illustrated in Figs. and
actuator located on the underside of the front frame
is coupled to the breaker's trip shaft via a trip rod
driven by the actuator arm.
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 actuator remains in the Reset po­
sition, the breaker can be closed and opened norm­
ally at will. However, when a closed breaker re­
ceives a trip 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 the br"eaker's main shaft. The
permanent magnet again holds the armature captive
in readiness for the next trip signal.
The trip device requires only one adjustment -
the trip rod length. As shown in Fig.
ance between the trip rod end and the trip shaft
0.125
paddle is gaged by a
20
)
MAI N
SHAFT
SIDE
VIEW
Fig. 22. Flux shift trip device and operating
linkages
23.
An electromagnetic
The actuator is a
24,
the clear ­
inch diameter rod. Ad -
RESET
Ll NKAGE
FRONT
0. 125 0. 015
just gap to inch+
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.
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 alternate method is 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
305183
tool Cat. No. is required for this method.
CAUTION:
IN THE EVENT THAT THE
SST TRIP DEVICE MUST BE RENDERED
INOPERATIVE
BREAKER TO CARRY CURRENT WITH­
OUT BENEFIT OF OVERCURRENT PRO­
TECTION, THE
METHOD IS TO
ROD BY TURNING ITS ADJUSTER END
FULLY CLOCKWISE.
ACTUATION OF
PADDLE.
�
VIEW
0
inch. To adjust, open
ALLOW THE
TO
RECOMMENDED
SHORTEN THE TRIP
THIS PREVENTS
THE TRIP SHAFT
In