Adjusting Contact Wipe And Pressure; Contact Sequence - GE AK-2-50 Maintenance Manual

Low Voltage Power Circuit Breakers GEK-7303
TABLE
Main Contacts
-
Intermediate Contacts
Arcing Contacts
No. or
Pres- Wipe No.
of
Pres- Wipe No. of Pre=r- Wipe
Breaker ontacts sure In In Contacts sure
In
ln Contacts
sure
In
Ill
Type
Per Pole
Lba,
Inches Per Pole Lbs, Inches
Per Pole Lbs, lnches
-
AK-SO
tor
AC 3 55 to 65
4/64 to 1 55 to 65
.
2 31 to 43
12/64 to
. '1/64
18/64
-
AK-SO
tor
DC 3 55 to 65
1/16 to
'1/64 .
1
55 to 65'
•
3
31 to 43 12/64 to
18/64
AK-75 tor AC
5 35 to 45 1/16
to
7/64
1
35 to 45
.
3
31 to 43 12/64
to
18/64
-
"35 to 45
1/16 to
12/64 to
-
AK-75 tor DC
5
I
35 to 45
•
5 31 to 43
?/64
18/64
- .
-
AK- I 00 for AC
8 25 to 35
1/16 to
2
25 to 35
•
5·
31 to 43
12/64 to
AK-100 tor DC
?/64
18/64
_ AKF-2C
3 55 to 65
1/16 to
.
1,
55 to 65
•
2
31 to 43
12/64 to
-
(Oulside Poles
.•.
'1/.64 .
187?4.
.
AKF-2D (Outside
5
55 to 65:.
1/16 io
I
55 to 65
• ·
3 31 to 43
12/64 to
AKF-2£' (Poles) ·:
'1/64
.
.
18/64
-
AKF•2C (Field
AKF-2D Discbarge
0
------- -----
Contacta)
0
-----··--
--
2 ..
10 io 16 28/64 to
40/64
..
-
• The intermediate conta~t wipe should
be
at le~t 1/16
in.
greater
than
main ·contact wipe.
~
• Ldt stationary contact ext;nda approximately 3/32 in.
~
1/32 further
than
right band contact.
against the stationary arcing contacts at . a point
measured in line with the breakbetweenthecontact
stop and the contact pivot block. Push the contact
backward until dimension ."B" ·recorded in item
2 is reached. The scale should then be read.
4. If
the pressure is not within the require-
ments listed on TABLE I, refer to the section
of these instructions dealing with ADJUSTING
CONTACT
WIPE
AND PRESSURE.
ADJUSTiNG ·coNTACT . WIPE
AND PRESSURE
(Fig.
6)
1. To obtain proper contact wipe andpressure
on the center pole, dimension "A" should be
increased to increase wipe and decreased to
decrease wipe.
· 2. To ch. a nge dimension "A" remove the clevis
pin (14) and rotate the clevis as necessary.
. 3. . To prevent overstressing the clevis threads
(13) dimension. "A" should not exceed 3/16 in. and
space . '.'A" should be filled with shims to 0.005 in.
of being solid.
· 4. With the proper center pole WiJ>e obtained,:.
moving· the crossbar adjusting plate {lOA) on the
center pole to the right will simultaneously
in-
crease the wipe on both outside. poles; moving
the adjusting plate to the left will have the reverse
effect.
5.
To increase ·the wipe on either outside pole
individually, move the crossbar adjustin~ plate of
that pole to the left; to decrease the wipe move
the adjusting plate to the right.
NOTE:
If
the proper contact pressure
does not exist when the contact y.,ipe is
within its limits, the stationary contacts
springs should be replaced. ·.
CONTACT SEQUENCE (Fig. 6)
On the horizontal plane, the difference in the
making
of the arcing contacts on the same pole
must
be no greater than 1/32 in.; the difference
~e~
tween arcing contacts on separate poles 1/16 m.
If
it is desired to advance or retard the closing
of the main contacts of a pole . l oosen the bolts
holding the adjustment plate (10A)
of
that pole
and slide plate to the left to advance con~ct
closing, or to the right
to
retard contact ~los~g
Make this adjustment on the outer poles, usmg
the center pole as a reference. Upon retight-
ening adjustment plate· bolts, make. sure the lock-
ing tabs are turned up a:r:ound bolt heads, locking
the bolts securely in p~ace. . . .
. Contact sequence· in the vertical plane should
be such · that when the . arcing contacts are just
touching, the intermediate contact gap should be