Replacement; Adjustment; Adj Ustment; Shunt Trip - GE AKR-30 Series Maintenance Manual

To check the setting, arrange the breaker for "slow­
close" as described in Section 7.4. Through the use of a
continuity 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 adjustable link and varying its length as required.
E LECTROSWITCH TYP E 1 01
Adjustment is the same as the GE S B 1 2 except that
when the switch "A" contacts touch, the breaker arcing
contacts m ust be w ithin 0 to .250 inches of c losing.
7.7

SHUNT TRIP

The shunt trip device opens the breaker when its coi l is
energ ized. An "A" auxi l i ary switch, which is closed only
when the breaker is closed, is in series with the device
coil . Connections are made to the external tri pping sou rce
through secondary disconnects on drawout breakers, or to
the terminal bo a rd on stationary breakers.
The shunt trip is mounted on the underside of the
breaker front frame as shown in Fig. 29. A second shunt
trip may also be mounted to the frame (see Fig. 30) if a se­
cond undervoltage device isn't already instal 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
d evice from the bracket. If a replacement or new device is
ordered, a mounting bracket will be s uppl 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. This
additional bracket is fastened by two of the hex head bolts
used to fasten the buffer assembly to the breaker frame.
7.7.2 ADJUSTM ENT
When these devices are i n stal led or replaced, their
positive abil ity to trip the breaker m ust be demonstrated.
This is done by placing a 1 /32-inch sh im between the ar­
mature and magnet of the device and manually operating
the armature to trip the breaker.
If the shunt trip is not successful in this test, check the
mounting fasteners to make sure they are reasonabl y
tight. If they-are, then bend the trip padd le on the trip shaft
to slightly reduce the distance between the trip arm of the
device and the trip paddle, and recheck for positive trip. If
this bending is necessary, be careful that it is not over­
done. Verify that there is a .030 "-.050 " gap between the
trip arm and the trip paddle with the breaker closed . A gap
greater than .050" is perm itted and m ay sometimes be
necessary in order to prevent n uisance tripping. Re-verify
positive trip as a final check.
7.8 UN D E RVOLTAG E DEVICE
The undervoltage device trips the breaker when its coil
is de-energized . The leads of the coil are connected
directly to secondary disconnects or to a terminal board .
U nder normal conditions, the coil remains energized and
t he 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 coil rating .
armature will render the breaker incapable of closing . The
armature will "pick up" and allow closing if the applied
voltage is 85% or more of the coil rating. It may also pick
u p at a lower voltage. Refer to table 2 5 for picku p and
dropout ranges.
The armature of the undervoltage device may be tied
closed in order to permit breaker operation d uring main­
tenance.
The undervoltage device is mou nted to the underside of
the breaker front frame as shown in Fig . 29.
A second undervoltage may also be mounted to the
frame (see Fig . 31) if a second shunt tri p isn't al ready
instal led, see Section 7 . 7 .
If a second undervoltage device is added, a new buffer
assembly block will be suppl ied.
clearance, in this case, the buffer assembly must be taken
off, disassembled, and remounted together with the
number two undervoltage device. Before disassembling the
orig inal buffer, carefully measure the distance between the
faces of the threaded members as shown in Fig. 31 , and set
this di mension carefu lly on the new assembly. Refer to the
breaker wiring diagram for the coi l lead connections.
7.8.1 REPLACEM ENT
To replace an undervoltage d evice, remove the mount­
ing bracket (shown in fig . 29) from the breaker frame and
remove the device from the bracket. Re-install in reverse
order, noting wire routing and secu ring means.
Set the gap between the trip paddle and device arma­
ture to approximately 0.030 inch as a starting point, then
proceed with the operational check (7 .8.2).
FIG. 30 - 2ND SHUNT TRIP INSTALLATION
An open
FIG. 29 - SHUNT TRIP AN D
UN DERVOLTAGE MOUNTING
This is required for
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