Instantanequs Undervoltage Tripping Device; Series Overcurrent Tripping Device - GE AK-1-15 Instructions Manual
Air circuit breakers
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Also See for AK-1-15:
- Instructions manual (31 pages) ,
- Installation and operation manual (7 pages)
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GEH-180'1 Air Circuit Breakers Type AK-I-15 and AK-1-25
REPLACEMENTS, FIG. 16
Coil
The only part of the undervoltage device that 1s
likely to require replacement during the life of the
breaker is the coil (15). 'l'he replacement procedure
follows:
1. Disconnect coil lea.cUJ.
2. Remove two screws (16), freeing magnet
(14) and coil (15) from device.
{It
may be
more convenient to remove the entire device
from its supporting. bracket (23) before
removing the magnet and coil.
If
the device
is of the time-delay type, bracket
(1)
will
also bave to be reJlloved from bracket (23).)
3. straighten laminations which were bent to
hold sbading'ring (5) inr.lace.
4. ReJllove sbading ring (5 •
.
5. straighten end of coil Clamp (13).
6. Remove coil, install new coil, andre-
assemble device
by
reversing disassembly
procedure.
(Note: -
It
is advisable to re-
place, the magnet and coil assembly as
nearly as possible in its exact original
position in relati.onto the device, frame.
Before removing the magnet, note or mark
its position relative to the frame.
Doing
this will result in baving the same open
air gap between ,armature and magnet and'
will insure the device's picking up at the
same voltage value).
Device
If
the entire device is replaced, simply remove
the bardware fastening the frame of the device to
supportln~
bracket (23).
If
a time-delay device,
bracket (1) must also be removed from (23).
ADJUSTMENTS
When the armature (3) is open (coil deener-
~ed)
it must pusl1 the trip paddle (22) .at least
1/32"
of
an" inch beyond the point at which the
breaker trips.
This may be checked by placing a
1/32" .feeler
gau~e
between the armature and the
head of screw (2) with the breaker in the closed
position and the armature held closed against the
magnet. When the armature is released, it should
JllOVe under the action of spring
(4)
just far enough
tc;»
trip the breaker.
This will ensure pOsitive
tripping of the breaker by the device. Adjustment
is
obtained by means of screw (20) which may
be
advanced towards the armature or retarded.
The armature pickup point isa function of the
open air gap of the armature. The air gap is set by
means of adjusting screw (2).
This gap shoul.d be
set so that the armature will "pick up" at 80% of
rated voltage.
In order to check this adjustment, a
variable voltage
so~ce
is necessary.
The gap
should be increased if "pick up" occurs at less
than
80% of voltage or decreased if it occurs at
more than 80%.
20
"Drop out" -andsubsequellt tripping of the
breaker is a function of the tension of spring (4).
This is a factory adjustment.
It should not be
necessary to ever reset this adjustment in the
field.
INSTANTANEOUS UNDERVOLTAGE
TRIPPING DEVICE
This undervoltage tripping device is constructed
similarly to the time delay undervoltage tripping
device with the exception that the cylinder (10),
{llun g .er (12), connecting rod (H), clevis (7), bracket
(1), and adjusting nut (8), as shown in Fig. 10 are
omitted.
The adjustments and replacements for this
device are also the same as those for the time
delay undervoltage tripping device.
SERIES OVERCURR:ENT •
TRIPPING DEVICE
There are two types of overcurrent trip devices
with which the breaker may
be
equipped.
These
are the EC-1 and the EC-2 devices. The principal
difference between these two is that the former may
bave time delay cbaracteristics which include a
short time delay.
The latter is used only for long
time delay and instantaneous cbaracteristics, or
combinations of these two. For a description of the
operation and adjustments of the EC-2 device, refer
.•...
~ .
to Instruction Book GEI-50216.
.
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
unit
base.
The EC -1 device can be provided with the
following tripping combinations:
1. Long time delay, short time delay and
instantaneous tripping.
2. LQng time and .short time delay tripping
only.
3. Long time delay and instantaneous tripping.
4. Short time delay and instantaneous tripping.
5. Short time delay tripping only.
6. Instantaneous tripping.
(a) Adjustable
(b) Nonadjustable
SHORT TIME DELAY TRIPPING, FIG. 17
The armature
(7)
is retained by calibrating
spring (8). After the magnetic force, produced by
an overcurrent condition, overcomes this restrain-
ing force, the aramature movement is further re-
tarded by an escapement mechanism which produces
an inverse time delay characteristic. Thl;' mecha-
nism is shown in the left side view of Fig.
17.
The pickup for this device can be field set
between limits baving a ratio of 2-1/2
to
1 in the
range of 200 to 1000% of the coil rating.
,
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