Series Overcurrent Tripping Device - GE AK-2-50 Maintenance Manual

·2. Mount the device
as
described under re-
placement and insert the pin which couples the
connecting rod and the trip paddle.
3.
Olos~ the breaker and insert a feeler
gage
1/32
in. thick between the armature and
magnet. . This should
be
done from . the rear
of the breaker. The feeler gage should be no
. wider ·
than 1/2
in. and at least
4
inches long.
. · 4. Close the armaµire agailµit the gage and
magnet. ·
5. · If
the breaker does not trip, form paddle
14
to obtain positive trip. · .
6.
Check visually to make sure that the
connecting rod does not restrict the engagement
of the breaker trip latch when the breaker mech-
anism resets. ·
It
should always be possible to
adjust
its
lelllrth to a DOint where resetting is
not interf erred with and yet positive tripping by
thA
overcurrent device is achieved.
SERIES OVERCURRENT
"TRIPPING DEVICE EC•1
·· (Fig. 27)
Each series overcurrent tripping device is
enclosed in a molded case and mounted by three
screws and a bracket to the lower part of the ·
pole ~t }?ase.
The devic. e · can . be provided with the same
tripping combinations as the EC~.1 direct acting
-device.
SHORT TIME-DELAY TRIPPING
(Fig.
27) . . .
. The armature
(7)
is restrained by cali-
brating spring
(8).
After the magnetic force
produced by an overcurrent· conc:Ution overcomes
~ this restraining force; the · armature movement
is
further ·retarded by an escapement mechan- .
ism which produces an- inverse . time delay char~
acteristic. The mechanism is shown on Fig.
27.
.
.
-
.
.
LONG TIME-DELAY TRiPPING . .
(Fig.
27) · . · . . ·
The armature (10) is restrained by the· calib-
ratio~ spring (11). · After the magnetic force
produced by an overcurrent condition overco~es
this restraining force, the armature movement
·is further retarded by the flow of silicone oil .
in a dashpot, which produces an inverse time
delay · characteristic. The · mechanism is shown
on Fig. 27.
INSTA~TAN.EOUS TRIPPING
{Fig.
27) .
· (a) Adjustable instantaneous tripping takes place
after the magnetic force produced by an over-
current condition, overcomes. the restrainingforce
of the calibration spring . which can be adjusted
by the calibration clamp nut (14). .
(b) · Non-adjustable instantaneous tripping takes
place after the magnetic force produced by an
overcurrent condition overco~es the restraining
Low Voltage Power Circuit Breakers
GEK-7303
force of a non-adjustable spring.
. ADJUSTMENTS
(Fig. 27)
Calibration clanu>ing nuts (14) are used to set
the desired pickup tor .. the adjustable elements.
.
.
. To adjust for approximately
1/32
in. over-
travel of trip arm
(19)
after tripping:
1.
Check trip latch ·engagement. See
AD-
JUSTMENTS - OPERA TING MECHANISM.
2.
Loosen the locknut• and turn the adjusting
screw
(9)
on the trip arm
(19).
The screw should
not touch the trip paddle when the .breaker is
"open". Adjust positive trip same
as
EC-2A
(See page
33 ). ·
3. Tighten the adjusting screw locknut• on the
trip arm.
• NOTE:
In
Ueu of loclmuts, some devices are
equipped with self-locking nylon insert nuts.
REPLACEMENT
(Fig.
27)
.
1.
Remove front frame (see SEPARATION
·OF FRONT
AND
REAR FRAMES).
2.
Remove the bolts holding the coil to the
-lower stud.
3. Remove bracket. and mounting screws.
. 4. ·
Before
installing
a new device, check the
travel of the trip arm with a rod or wire and
Fig. 28 (8016188) Checking travel distance
of series overcurrent tripping device