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turns to provide contact wipe. Tighten the locknut.
Unwind the backstop screw
locknut which secures the backstop screw to its
support.
Finally, adjust the tension on the
ary contact brush such that, when the contacts are
made and fully wiped in, there is approximately an
equal deflection on each brush.
TORQUE ADJUSTMENT
Connect the current operating and current
polarizing coils in series by connecting a jumper
across terminals 6 and 7. Apply current to ter-
minals 5 and 6 and adjust the directional unit
spring so that the unit picks up at 0.5 ampere.
The core of the directional unit has a small
flat portion, the
the effect of bias torques produced on the rotor.
Such torques can be produced by any one of the
operating or polarizing quantities acting alone with
the other two circuits de-energized. Theadjustment
of the core is made at the factory, but may be check-
ed by observing that the unit responds as outlined
below:
Short out the potential
minals 9 and
leaving the current polarizing
coil (terminals 7 and 8) unshorted. Supply 30 am-
peres through the operating coil (terminals 5 and 6)
and check that the unit does not operate.
If the unit does not satisfy the above condition,
rotate the core to a position which causes it to do
so.
The core can be turned by loosening the large
hexagonal nut at the bottom of the unit and turning
the core by means of the slotted bearing screw.
This screw should be held securely in position when
the nut is retightened.
Keep in
that 30 amperes
current coils to overheat if left on too long. There-
fore, leave the test current on only for shot inter-
vals and allow sufficient time between tests for the
coils and
to cool.
CLUTCH ADJUSTMENT
The connections show" in Fig. 15 for the polar-
ity check can also
used in making the clutch ad-
justment. The clutch should be
It is recommended that sufficient quantities of
renewal parts be carried in stock to enable the prompt
replacement of any
When ordering renewal parts, address the
Courtesy of NationalSwitchgear.com
Ground Directional
turn and tighten the
of which is to minimize
coil (ter-
cause the
RENEWAL PARTS
broken, or damaged.
potential or current polarization, not both. The 50
ohm resistor should be replaced
resistor capable of providing the current range
listed in Table V
screw, projecting from the side of the moving con-
tact
controls the clutch pressure, and
quently the current value at which the clutch will
slip.
With rated frequency (and at rated volts for
polarization), the clutch should be set to
slip
the current values listed in Table V.
TABLE V
CLUTCH ADJUSTMENTS
Method Of
Tap Range
Polarization
Current
Current
Current
Potential
Potential
For cleaning fine silver contacts, a flexible
burnishing tool should be used. This consists of a
flexible strip of metal with an etched roughened
surface, resembling in effect a superfine file. The
polishing action is so delicate that no scratches are
left, yet corroded material will be removed rapidly
and thoroughly.
The flexibility
the cleaning of the actual points of contact.
Fine silver contacts should not be cleaned with
knives, files or abrasive paper or cloth. Knives or
files may leave scratches which increase arcing and
deterioration of the contacts. Abrasive paper or
cloth may leave minute particles of insulating ab-
rasive material in the contacts thus preventing
contact closing.
The burnishing tool described above can be
obtained from the factory.
nearest Sales Office of the General Electric
pany, specify quantity required,
and
complete nameplate data. If possible, give
the
Electric Company requisition number
on which the relay was furnished.
GEH-2032
Relay Type IBCG
an adjustable
relay rating in question. A
Amperes For
Clutch To Slip
10-15
10-15
20-25
7-10
7-10
12-15
the tool Insures
of partwanted,
13
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