Basic Breaker Components - GE AK-1-15 Instructions Manual

Air Circuit Breakers Type AK-1-15 and AK-1-25 GEH-1807
TROUBLE SHOOTING
TROUBLE
CAUSE
REMEDY
Failure to Close
Latch return spring too weak or broken.
Replace spring.
and Latch
Hardened or gummy lubrication on
Clean bearing and latch
bearing and latch surfaces.
surfaces.
Closing solenoid burned out.
Replace solenoid coil.
Solenoid control device not functioning
Re-adjust or replace device.
properly•
BASiC BREAKER ·COMPON.ENTS
ARC QUENCHER
Each arc quencher (see Fig. 3) has several
compolJIld inside barriers (2) containing' a large
number of perforations and two o\ltside barriers (3)
without perforations, as well as a front cap (4) and
a rear support (24) held in place by a fiber strap
(23). A clamp (5) is attached to the breaker base
by two bOlts. Clamp (5) holds all the arc quencher
assemblies to their respective pole units. A muf-
fler (1) is located on top of the compound barriers.
The compound barriers and the muffler, together
with the slots between the barriers, serve to ex-
tinguish the arc. '
The arc quenchers sh(ijJ],d be inspected at the
regular inspection period and' parts replaced, if
badly burned or corroded.
REPLACEMENT, FIG. 3
1. Remove clamp (5) by removing two bOlts.
2. Unclasp fiber strap (23).
3. Remove front cap (4), muffler (1), outside
barriers (3), inside barriers (2) and rear
support (24).
4. Install new or disassembled parts in re-
verse order.
NOTE: In re-assembling the rear suppod (24)
to the breaker, be sure and push the rear support
toward the top of the pole unit so that the clearance
in the rear support will accommodate the screw-
head of the back plate. .
POLE UNIT
ASSEMBLY
The contact assembly of each pole unit con-
sists of a stationary and a movable contact sub-.
assembly. Refer to Fig. 6.
The stationary contact assembly consists of
parallel contact fingers (3) with silver alloy tips,
the. upper stud (20) and pins (4) with compression
springs (19) which provide continuous contact pres-
sure between the contact fingers and the upper
stud (20). A shunt (21) is used to prevent pitting
at the pivot point of the stationary fingers when
carrying high momentary currents. .The station-
ary contact fingers are. held in place by the upper
stud cap(6). .
The movable contact assembly consists of
parallel contact arms (5) with silver alloy tips, a
contact carrier (18) with a spring (17) which pro-
vides continuous contact between the contact arms
and Pin.
(11».
A clamp (14) secures pin (15) to the
contact support (16). A flexible connection (12) is
provided to prevent pitting .at the pivot point of the
movable contact arms when carrying high mO:D:\en-
. tar:Y currents.
The movable contact assembly is connected to
the
main
shaft (16), Fig. 3, by an insulating link (7)
for operating the contacts 'When the breaker closes.
A definite amount of contact pressure. (see "Meas-
uring Contact Pressure") must be exerted by the
movable contacts against the stationary contacts.
A definite amount of contact wipe, or the distance
that the stationary contacts are pushed to the rear
by the movable contacts (see "Measuring CO;ntact
Wipe"), must result during the closing operation.
Both contact pressure and contact wipe should be
checked at the regular inspection period.
MEASURING CONTACT PRESSURE, FIG. 6
1.
Remove arc quencher (see "Replacements"
under Arc Quencher).
2. Place a push-type scale against the upper
end of the stationary contact tip (3) with
the breaker closed.
3. Exert pressure against the push-type scale
until the contacts just part. When the con-
tacts part the scale should register between
4 and 6 pounds.
4. Re-assemble parts in reverse order.
MEASURING CONTACT WIPE, FIG. 6
1. Remove arc quencher (see "Replacements"
under Arc Quencher). . .
2. Measure the dimension between the inside
surface of the pole base and the top edge of
the stationary contact tip (3), (a) with the
breaker open, (b) with the breaker closed.
3. The difference· between these two measure-
ments should be within the limits of 3/32"
and
1/4'"
If not within this range, the con-
tact wipe must be adjusted.
4. With the breaker closed, the stationary con-
tacts should have a minimum of 1/16"
overtravel, measured at the contact tips,
before reaching the limit of their movement
in the direction of closing.
5. Replace arc quencher.
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