Electrical Closing Devices And Controls; Protective Devices; Cut-Off Switches; Static Time Delay Under-Voltage Tripping Device - GE AK-2-50 Maintenance Manual

. AKF BREAKERS
(Fig. 20) .
. The . auxiliary switch mounting and linkage ··
on the
.AKF
breakers are different. from that of the
standard AK breakers. Figures 17 and 19 show
the difference
in
the mounting positions, with
the AKF switches rotated 90 degrees with respect
to the mounting position of the standard breaker
switch. There is also a s~ight difference between
the linkage · of the AKF bre·~er. switches, however
the principle of oper ation remains the same.
When the breaker operates, the movement of
the crossbar
(4)
rotates triangular link
(11)
about
fixed center
(1).
This rotational motion is trans-
mitted to the auxiliary- switch shaft (3) by the
linkage comprised
of
links (10), (8) and (6) . The
breaker position indicator is also operated by
this mechanism ·through link
(12). ·
ReplaceiMnt
(Fig. 20)
1. Disconnect all leads to . auxiliary switch.
2. - Remove mounting .. bolts_ (2) and (7).
3.
Withdraw auxiliary switch.·
4. Insert new switch with arrowonshaftpoint-
ing up and towards the back of the breaker as in
Fig. 18.
5. Replace _ m ounting hardware and wiring.
A djustments
(Fig. 20) _
The auxiliary switch operating rod
(5)
should .
be adjusted so that the switch "a" contacts close
when the arcing contacts of the outer poles are
parted by
1/8
to 1/4 in. -.This dimension may be
checked in the same manner described for the
standard breakers. The length of the operating
rod may be varied by . changing dimension "a"
(see Fig.
19)·
and aligning the operating rod
as
describ~d for t!_le standar<:I ~reakers.
ELECTRICAL CLOSING DEVICES
AND CONTRO~
-
· A
closing switch and motor mechanism are
provided for closing the breaker electrically.
CLOSING SWITCH
The closing button, when provided . is mounted
on the front frame behind the escutcheon.
A
hole is
provided in the escutcheon to allow operation of.the
switch. Remove the escutcheon to gain access
to the switch.
CUT.;OfF SWITCHES
(Fig. 21)
The motor cut-off switches are mounted on the
side of the front frame . When the breaker control
circuit is energized the motor circuit is main-
tained .through the closed contacts of switch
(1),
thus
charging the closing springs. At the end of the
charging stroke the cut- off switch is mechanically
operated by the charging of the springs and
Low Voltage Power Circuit Breakers GEK-7303
through the operating rod (4), thus opening switch
(1)
contacts and closing switch
(3)
.contacts. This
opens the motor circuit until a closing signal
is given. When a closing signal is given the motor
is energized through .switch
(3)
contact, further
charging. the closing springs and closing the
breaker. When the breaker closes, the cut- off
switch is again mechanically operated, reverting
to its original position with switch
(1) contact now
closed and switch
(3)
open, thereby allowing the
motor to charge the closing springs for a sub-
sequent closing operation. Most breakers have two
normally open auxiliary contacts in series with
the motor circuit to prevent pre- charging the
closing springs with the breaker closed.
If
the switches do not function properly, they
should be replaced by disconnecting the wiring
and removing them from their mounting bracket.
I
I
- ---+--- - -8
cin=r---,..- - -7
6
. : _j'-
L .. - ..
Fig. 21 (242C599) Motor cut- off switch
1. 'G' Switch
2. Insulation
5.
Retaining Ring .
· 6. Lever Bracket
3. 'F ' Switch
7. Mounting Bracket
4. Rod
8. Cover-
CONTROL RELAY
The control relay · is mounted on the left side
of the front frame. It is used to open and close
the motor circuit. To r eplace. remove wiring
and holding screws. See item 3, Fig. 2. ·
PROTEalVE DEVICES
STATIC T I ME DELAY UNDE.R-
VOL TAGE TRIPP I NG ·oE·v1cE
(Fig. 22)
The Static Time Delay Undervoltage Tripping