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T Y P E K C-4 R E LAY
41-776.1A
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MULT I PL E S OF TAP VAL U E CURRENT
629A576
Fig.
7
Maximum Pick-Up and Drop-Out Time. Curves for
the Phase Overcurrent Unit
Phase
&
Ground overcurrent Unit
The moving contact assembly has been factory
adjusted for low contact bounce performance and
should not be changed.
The set screw in the stationary contact has been
shop adjusted for optimum follow and this adjustment
should not be disturbed.
1. The upper pin bearing should be screwed
down until there is approximately 1/64" clearance
between it and the top of shaft bearing. The upper
pin bearing should then be securely locked in position
with the lock nut . The lower bearing position is fixed
and cannot be adjusted.
2 . The contact gap adjustment for the overcur
rent unit is made with the moving contact in the reset
position, e . e .. against the right side of the bridge .
Advance the stationary contact until the cont acts
just close. Then back off the stationary contact 2/3
of one turn for a gap of approximately . 020. " The
clamp holding the stationary contact housing need
not be loosened for the adjustment since the clamp
utilizes a spring-type action in holding t he stationary
contact is position.
3. The sensitivity adjustment is made by vary
ing the tension of the spiral spring attached to the
moving element assembly. The spring is adjusted by
placing a screwdriver of similar tool into one of the
notches located on the periphery of the spring adjuster
and rotating it . The spring adjuster is located on the
underside of t he bridge and is held in place by a
spring type clamp that does not have to be loosened
prior to making the necessary adjustments.
Insert the tap screw in the minimum value tap
setting and adjust the spring such that the contacts
will close when energized with the required c urrent .
The pick u p o f the overcurrent unit with the tap screw
in any other tap should be within ±5% of tap value .
If adjustment of pick-up current in between tap
settings is desired , insert the tap screw in the next
lowest tap setting and adjust the spring as described .
It should be noted that this adjustment results in a
slightly different time characteristic curve and burden .
Indicating Contactor Switch (ICS.)
Close the main relay contacts and pass sufficient
d-e current through the trip circuit to close the con
tacts of the
res.
This value of current s hould b e not
greater than the particular
res
tap setting being used.
The operation indicator target should drop freely.
The contact gap should be approximately . 047"
b etween the bridging moving contact and the adjust
able stationary contacts . The bridging moving contact
should touch both stationary c ontacts simultaneously.
RENEWAL PARTS
Repair work can be done most satisfactorily at
the factory. However. interchangeable parts can be
furnished to the customers who are equipped for doing
repair work. When ordering parts. always give the
complete nameplate data.
11
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Summary of Contents for KC-4
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