GE AKR-30 Series Maintenance Manual page 24

SECTION 7-Breaker Maintenance (Cont.)
FIG. 2N D UN DERVOLTAGE DEVICE
31 -
7.8.2 OPERATIONAL CH ECK
When the undervoltage device is used as part of a shut
down circuit which opens the breaker by deenergizing the
coil, the following operational check should be made. It is
recommended that this check be performed every 12 mon­
ths or every 1 7fiJ operations for AKR
operations for AKR fiJ I AKRT fiJ breakers.
1 . Check the trip latch engagement as described in Sec·
tion 7.15. Trip Latch Adjustment
2.
Check the torque required on the trip shaft to trip the
closed breaker. The value must be 24 inch-ounces max·
imum.
3. Check the response time required to go from zero volts
the coil
across undervoltage
ing. This time should be 20 to
If steps 1 and 2 above are acce p table,
time is too high, refer to Section 7 .8.3.
7.8.3 ADJUSTM ENTS
It
is recommended that the following checks be made at
the intervals given In Section 7 .8.2.
1 . Hold the armature against the magnet as shown in
32A
Fig. and check the following:
a
The rivet can tum free l y.
b. There is no binding between the armature pivot and
the shading ring.
.CX)1
c. There is a to .010 inch clearance between
rivet and armature as shown In Fig. 32A.
measurement should be made at the outer edge of
the armature where Its constant radius Is closest to
the rivet.
24
500
breakers and
30
to the breaker contacts open­
fiJ
milliseconds.
but
the response
This
FIG. 32A - UNDERVOLTAGE DEVICE
If excessive clearance or binding exists, loosen the
screws holding the magnet assembly to the frame and
move the magnet up or down as necessary. Tighten the
32
screws to 27 to
2.
The air gap between the armature and magnet with the
undervoltage device de-energized should be
Check the gap by inserting a .201
between the armature and magnet as shown in Fig.
necessary reset the air gap adjusting plate so that the gage
pin fits. Tighten the adjusting plate screw to
and cover it with RTV
3. Check the pick up voltage level with the undervoltage
device mounted on the breaker. Refer to Table
allowable voltage ranges.
should be made at the breaker's secondary d isconnects
and with the undervoltage coil energized. The coil should
also be close to roo m temperature (approx. 20-240C) when
taking voltage measurements. The coil resistance will in­
crease as its temperature increases and will change the ac­
tual pick up level.
If necessary, the pick up level is changed by using the
adjustment screw shown in Fig. 32A. Remove the locking
wire, tum the screw clockwise to raise the pick up level and
counterclockwise to lower. Once the pick up level is set, In­
stall the locking wire. Allow t�-coil to coo l and then
recheck the pick up level with 3 quick measurements.
OPEN GAP
ADJUSTMENT
the
FIG. 328 - OPEN GAP CHECK
in-lbs.
±
.005
diameter gage
9
.
The voltage measurements
.25
inches.
328.
If
to 1 1 inches
23
for the