GE IFC66A, Инструкция по эксплуатации

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GEK-45376
S
E
RVICIN
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TIME OVERCURR ENT U N I T
If it is found during instal l ation or periodic testing that the time overcurrent unit is out of l imits,
the unit may be recal ibrated as fol l ows:
Pickup Tests
Rotate time dial to No. 0 time-dia l setting and check by means of a l amp that the contacts just cl ose.
The point at which the contacts _Jst cl ose can be adjusted by running the stationary contact brush in
or out by means of its adjusting screw. This screw shoul d be hel d securel y in its support.
With the contacts just cl osing at No. 0 time setting, there shoul d be sufficient gap between the
stationary contact brush and its meta l backing strip to insure approximatel y 1 /32 inch wipe.
The pickup of the unit for any current tap setting is adjusted by means of a spring-adjusting ring.
By turning the ring the operating current of the unit may be brought into agreement with the tap setting
empl oyed if for some reason, this adjustment has been disturbed. This adjustment a l so permits any desired
setting intermediate between the various tap settings to be obtained. If such adjustment is required, it is
recommended that the higher tap setting be used. It shoul d be noted that the rel ay wil l not necessaril y
agree with the time current characteristics of Figures 6 and 7, if the re l ay has been adjusted to pickup
at a va l ue other than tap va l ue, because the torque l eve l of the rel ay has been changed.
Connect the operating coil terminal s to a source of the proper frequency and good waveform having a
vo l tage of 1 1 0 or more, with resistance l oad boxes for setting the current. See TEST C I RCU IT Figure 1 5 .
With the tap bl ock set for the l owest tap and the time dial set where contacts are just open, adjust the
control spring to just close the contacts within the l imits given bel ow which are p l us and minus 1 percent
of the tao amps. See Tab l e 1 3 .
TABL E 1 3
Tap Range Tap Min. Amps
Max. Amps.
0 . 5- 4 0. 5
o.
495
0. 505
l . 0 - 1 2. 0 1 . 0
0. 99
1 . 0 1
It shoul d never be necessary to wind up the control spring adjuster more than 3 0 degrees (one notch ) or
unwind it more than 1 20 degrees (three notches ) from the factory setting to obtain the above pickup setting.
Time Tests
With the tap b l ock set for the l owest tap and the time dial at No. 5 setting, appl y five times tap
current to the rel ay.
Adjust the position of the drag magnet assembl y to obtain an operating time as l isted in Tab l e 1 4.
TABLE 14
Rel ay
Time
Min. Max.
I FC66 1 8. 2
1 9. 0
However, it woul d be preferabl e to adjust the operating time as near as possibl e to 1 8. 6 seconds. The
drag magnet assemb l y shou l d be approximate l y in the m idd l e of its travel . The drag magnet assemb l y is
adjusted by l oosening the two screws securing it to the support structure. See Figure l . Moving the drag
rr·
'et towards the disk and shaft decreases the operating time and moving the drag magnet away from the
l
and shaft increases the operating time. The screws securing the drag magnet assemb l y to the support
structure must be tight before proceeding with other time checks.
14
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