Replacement Of The Auxiliary Switch; Replacement Of Motor Cut-Off Switch; Replacement Of Trip Latch Reset Check Switch; Replacement Of Ls3 - Mid-1991 And After - Siemens SGIM-3268H Manual

Figure 42: Motor Cut-Off Switch (LS1) and Spring Charged
Switch (LS2).
Figure 43a: Trip Latch Reset Switch (LS3) (From mid-1991
to present).
Courtesy of NationalSwitchgear.com

Replacement of the Auxiliary Switch

Figure 41 shows the auxiliary switch and its key mounting
components. Two mounting screws hold the switch to the
mounting bracket. First remove the quick disconnect
terminals after marking their position. The screw, washer
and nut connecting the switch's operating lever to the
operating shaft is removed, and then the two mounting
screws. Re-assemble in reverse order.
Replacement of Motor Cut-Off Switch (Device LS1) and
Spring Charged Switch (LS2)
The motor cut-off switch (LS1) and spring charged switch
(LS2) form a common assembly of two switches on one
mounting bracket. Should either switch require replace-
ment, it is recommended that both be replaced as a single
assembly. The motor cut-off switch (LS1) is the "outboard"
device with respect to the mounting bracket. Removal of
the two mounting screws shown in Figure 42 allows both
switches to be brought out for convenient removal of the
interconnecting wiring.
Next, mark all wires to both switches. Remove the wires.
Then replace the switches, rewire, and reassemble the
switches to their mounting bracket. Be sure to use the
same flat washer, lock washer and nut configuration in
reassembly as was present in the as-shipped condition.

Replacement of Trip Latch Reset Check Switch

(Device LS3)
Note: Two different latch systems have been used in GMI
circuit breakers, with changeover from one design to the
other occurring in mid-1991. This instruction manual de-
scribes both designs.
Pages 11-13 describe the operation of the mechanism
used beginning in approximately mid-1991.
Pages 13-15 described the operation of the mechanism
used from 1989 until approximately mid-1991.

Replacement of LS3 - Mid-1991 and After

The following paragraphs describe replacement of the trip
latch reset switch for the mechanism used beginning in
approximately mid-1991.
This mechanism can be identified by observing the close
latch above the spring charging motor on the left side of
the circuit breaker. Refer to Figure 18. The close latch is
installed on the close shaft assembly 72, and includes a
hardened latch face. This face contacts a bearing which is
part of the close hatchet assembly 105. If the mechanism
has a close hatchet which bears directly on the close
shaft, refer to the next section for replacement of the trip
latch reset switch for your mechanism.
Overhaul
33