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3. Percentage Slope Characteristic
Connect the relay per the test circuit of Figure
11. Pass 20 amperes for the CA-16 and 14
amperes for the CA-26 relay into terminals 9 and
19 of the relay. Adjust the plug (when used) in
the operating electromagnet until the contacts
just close with the following currents into the
operating circuit of the relays.
1. CA-16
2. CA-26
4. Time Curve
Place the permanent magnet on the relay and
apply 20 amperes to terminals 12 and 13 of the
relay. Adjust the keeper of the permanent mag-
net until the contacts just close in the following
times.
1. CA-16
2. CA-26
These times should be the average of 5 read-
ings.
5. Indicating Contactor Switch (ICS)
Close the main relay contacts and pass sufficient
dc current through the trip circuit to close the
contacts of the ICS. This value of current should
not be greater than the particular ICS tap setting
being used. The operation indicator target should
drop freely.
6. Indicating Instantaneous Trip Unit (IIT)
The core screw must be adjusted to the value of
pick-up current desired. It is recommended that
the IIT be set to pick-up at a value of current that
is equal to the maximum rms symmetrical exter-
nal fault current to the relay.
Courtesy of NationalSwitchgear.com
29.4 to 34 amperes
36 to 40 amperes
52 ± 5% Milliseconds
72 ± 5% Milliseconds
7. Sensitive Fault Detector
Loosen the lock nut at the top of the element and
run the core screw down until it is flush with the
top of the lock nut. Back off the Micarta disc by
loosening the two lock nuts. Apply 0.15 amperes
to terminals 14 and 15. Operate the moving ele-
ment by hand and allow the current to hold the
moving contact disc against the stationary con-
tacts. Now, screw up the core screw slowly. This
causes the plunger to move up, compressing the
spring until a point of maximum deflection is
reached. Further upward motion will cause the
plunger to drop part way out of the coil, thus
diminishing the spring pressure on the contacts.
By thus adjusting the core screw up or down the
maximum spring deflection for this value of cur-
rent may be found. Then lock the core screw in
place. Next, adjust the de-energized position of
the plunger by raising the Micarta disc until the
plunger just picks up electrically at the 0.15
ampere value.
8.1.
Electrical Checkpoints
Figures 12 and 13 will aid in trouble shooting either
the CA-16 or the CA-26 relays. These curves show
the operating current to trip the relay for different
restraint current for one restraint element as well as
for six restraint elements connected in series.
9. RENEWAL PARTS
Repair work can be done most satisfactorily at the
factory. However, interchangeable parts can be fur-
nished to customers who are equipped for doing
repair work. When ordering parts, always give the
complete nameplate data.
41-337.3L
11
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