GE AK-1-15 Instructions Manual page 22

GEH-1807 Air Circuit Breakers
Type
AK-1-15 and AK-1-25
fig. 19 Typical TIllie-Current Characteristic
A'
of Ee-l Overload Device .
"J
)
-
0 0
00
co
2
-
.Q • • • . . .
~
"~
G
CU~NT
IN TIMES ffiEAKER RATIN
\ I I I
I I I
I
I
LONG
TIME
DELAY PICK-UP AO./US'i'AllLE
FROM .8 TO
!.II
TIMES 8REAKER RATING
TIME ADJUSTABLE IN FACTORY AT-
~
lID,lS OR 5 SECOrQl (IA 18 OR IC
( RESPECTIVELY) AT 800
i:
OF
LOHG
~
TIME DELAY
PlCK~
UP
~ "" I I
~~
"I":
SHORT TIME DELAY PICK-uP
'\
ADJlf.~~~Li,J:~
2
R,%13G-
""
'-l;,"
~1TH!e.. MAXIMUM RATIO
4l!
TO I
v-
I I
~IAXIMUM
BREAKER
LEARIN6 TIME
- MINIMUM
-
RESET TIME,
INSTANTANEOUS PICK-UP
SET IN MCTORY AT 10
~
~~TfJl
TIMES BREAKER
............
...."
1'\
~
:'\
TIME ADJUSTABLE IN _ ~
MAXIMUM BREAKER
FACTORY AT 0.:599, r:.266
OPERAYING TIME
OR 0.133 SECONDS 2A,
2B OR 2C RESPECTI VELY)
~~
AT 250" OF SHORT TIME
DELAY
1
PICK-I UP I I
I
1
I
II
~~
I I!
a
4
III .,
10
20 110 100 0
.02
.01
.06
2 0
CURRENT IN TIMES BREAKER RATING
.2
100
1000
200
20
110
10
2
II
Z
o
~
2
(/)
:z
w
::i!E
5
i=
REVERSE CURRENT TRIPPING
DEVICE
The device is enclosed in a molded case and
is mounted on the right pole base similarly to the
series overcurrent tI'ipping device.
The reverse current tripping device (see Fig.
20) consists of a series coil (1) with an iron core
mounted between two pole pieces (7), also a poten-
tial coil
(4)
connected across a constant source of
a,
voltage and mounted around a rotary-type arma-
WI
ture (6). Calibration spring (3) determines the
armature piCk-up when a reversal of current occurs.
6. Check overtravel of trip arm (19).
If
ad-
justment is necessary, it whould be done now,
when the adjustment screws are accessible,
rather than after the breaker is completely
reassembled.
7. Complete the reassembly of the breaker.
NOTE; No component parts of the overcurrent
tripping devices are replaced. It will be necessary
to install a new device when parts are worn or
damaged.
1. Follow steps 2 to 11 inclusive of procedure
for replacing breaker mechanism.
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 push the armature solidly against the
magnet (see Fig. 18). The trip arm should
move at least 5732".
If
there apJlears to be
insufficient movement of the trip arm, or
if the armature appears to be binding, the
device should 'not be used.
5. Mount new trip device on pole unit. Be sure
that allen head bolts which fasten series
coil (1) are not cross-threaded and are
firmly tightened down.
1£
there is not good
contact pressure against the stud, overheat-
ing and burning may result.
Fig. 18 Checking Travel Distance of Trip Arm
on series Overcurrent Tripping Device
ADJUSTMENTS, FIG. 17
Calibration clamping nuts (14)
are used to set
the desired pickup for the adjustable elements.
In
order to insure positive tripping by the over-
cqrrent trip device, the trip arm, (19) Fig. 17,
must have a minimum of lY32" overtravel beyond
the point at which the breaker trips.
In
order to
check this overtravel, a probe may be used as illus-
trated in Fig. 18, the overtravel distance being
conSid.ered at the point of contact between the triJ?
arm and the adjusting screw of the trip paddle, (18)
Fig. 17. Adjustment of overtravel is made by
means of the adjusting screw in the trip paddle on
the trip shaft. The screw in the trip arm is not
intended for adjustment purposes.
REPLACEMENT
22