GE AKR-30 Series Maintenance Manual page 201

To check the setting, arrange the breaker for "slow­
close" as described in Section 7.4. Through the use of a
conti n u ity tester, observe the position of the breaker con­
tacts when the switch "A" contacts touch. At this point the
breaker's arcing contacts must be within .250" to . 500" of
closing.
Adjustment is made by disconnecting the upper end of
the adj ustable link and varying its length as requ i red.
ELECTROSWITCH TYPE 1 01
Adjustment i s the same as the GE S B 1 2 except that
when the switch "A" contacts touch , the breaker arcing
contacts must be within 0 to .250 inches of c losing.
7.7 S H U NT TRIP
The shunt trip device opens the breaker when its coil is
energ ized. An "A" auxi liary switch, which i s closed only
when the breaker i s closed, i s i n series with the device
coi l . Connections are made to the external tripping source
through secondary discon nects on drawout breakers, or to
the terminal bo a rd on stationary breakers.
The shunt trip is mou nted on the underside of the
breaker front frame as shown in Fig.
trip may also be mounted to the frame (see Fig. 30) if a se­
cond undervoltage device isn't al ready i nstal led, see Sec­
tion 7.8.
7.7.1 REPLACEM ENT
If it is necessary to replace or add one of these devices,
the easiest procedure is to remove the mounting bracket,
shown in Fig. 29, from the breaker frame and remove the
device from the bracket. If a replacement or new device is
ordered, a mounti ng bracket will be suppl ied with the
device.
If a second shunt trip is added, this is mounted by
means of an additional bracket as shown in Fig. 30. Th is
additional bracket is fastened by two of the hex head bolts
used to fasten the buffer assembly to the breaker frame.
7.7.2 ADJ USTM ENT
When these devices are i nstalled or replaced, their
positive abil ity to trip the breaker m ust be demonstrated.
This is done by placing a 1 /32-i nch shim between the ar­
mature and magnet of the device and manual ly operating
the armat ure to tri p the breaker.
If the shunt trip is not successfu l in this test, check the
mounting fasteners to make sure they are reasonably
tight. If they-are, then bend the trip paddle on the trip shaft
to slightly reduce the distance between the trip arm of the
device and the trip padd le, and recheck for positive tri p. If
this bend ing is necessary, be carefu l that it is not over­
done. Verify that there i s a .030 "-.050 " gap between the
trip arm and the trip paddle with the breaker closed . A gap
greater than .050" is permitted and may sometimes be
necessary in order to p revent n uisance tripping . Re-verify
positive trip as a final check.
7.8 U N DERVOLTAG E DEVICE
The undervoltage device trips the breaker when its coil
is de-energized. The leads of the coil are connected
directly to secondary d isconnects or to a terminal board .
Under normal conditions, the coil remains energized and
the breaker may be closed .
Dropout of the armature, with resultant breaker trip­
ping, occurs when the voltage is reduced to a val ue
between 30% and 60% of the coi l rating.
armature will render the breaker i ncapable of closing. The
armature will " pick u p" and allow closing if the applied
voltage is 85 % or more of the coi l rating. It may also pick
u p at a lower voltage. Refer to table 25 for pickup and
d ropout ranges.
closed in order to permit breaker operation during mai n­
29.
A second sh unt
tenance.
the breaker front frame as shown i n Fig. 29.
frame (see Fig . 3 1 ) if a second shunt trip isn't already
instal led , see Section 7. 7.
assembly block wi l l be suppl ied.
clearance, in this case, the buffer assembly m ust be taken
off, disassembled, and remounted together with the
number two undervoltage device. Before disassembling the
origi nal buffer, carefu l ly measure the distance between the
faces of the threaded members as shown in Fig. 31 , and set
this di mension carefully on the new assembly. Refer to the
breaker wiring diagram for the coi l lead connections' .
7.8.1 REPLACEM ENT
ing bracket (shown in fig . 29) from the breaker frame and
remove the device from the bracket.
order, noting wire routing and securing means.
ture to approximately 0 . 030 inch as a starting point, then
proceed with the o perational check (7 .8.2).
An open
FIG. 29 - SHUNT TRIP AND
UN DERVOLTAGE MOUNTING
The armature of the undervoltage device may be tied
The undervoltage device is mounted to the underside of
A second undervoltage may also be mou nted to the
If a second undervoltage device is added, a new buffer
To replace an undervoltage device, remove the mou nt­
Set the gap between the trip paddle and device arma­
BREAKER
F RONT FRAME
;;: D SHUNT TR IP
FIG. 30 - 2N D SH UNT TRIP INSTALLATION
Th is is required for
Re-i nstall in reverse
MT BRACKET
RIGHT
HAND
BUFFER
23