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GEK—49850
INSTANTANEOUS UNIT (NON-DIRECTIONALLY CONTROLLED)
Make sure that the instantaneous unit is in the correct range in which it is to operate.
See the
internal connections diagram and Table 6.
Whenever possible, use the higher range since the higher range
has a higher continuous rating.
The instantaneous unit has an adjustable core located at the top of the unit.
To set the instantaneous
unit to a desired pickup, loosen the locknut and adjust the core.
Turning the core clockwise decreases
the pickup, turning the core counterclockwise increases the pickup.
Bring up the current slowly until the
unit picks up.
It
may
be necessary to repeat this operation, until the desired pickup value is obtained.
Once the desired pickup value is reached, tighten the locknut.
CAUTION
-
Refer to Table 6 for the continuous and one second ratings of the instantaneous unit.
Do not
exceed these ratings when applying current to the instantaneous unit.
The
range of the instantaneous unit (See Table 6) must be obtained between a core position of 1/8 of
a
turn
of
full clockwise and 20 turns counterclockwise from the full clockwise position.
INSTALLATION
LOCATION
The location should be clean and dry, free from dust and excessive vibration and well lighted to
facilitate inspection and testing.
MOUNTING
The relay should be mounted on a vertical surface.
The outline and panel drilling diagram is shown
in Fig. 24.
CONNECTIONS
The internal connection diagrams for the various relays are shown in Figs. 5 to 7.
Typical wiring
diagrams are shown by Figs. 8 and 9.
Since phase sequence is important for the correct operation of Type
JBCV relays, the rotation specified in Figs. 8 and 9 must be adhered to.
Unless mounted on a steel panel
which adequately grounds the relay case, it is recomended that the case be grounded through a mounting
stud or screw with a conductor not less than #12 B&S gage copper wire or its equivalent.
Terminal 12 of JBCV relays should be connected to the negative side of the DC bus.
INSPECTION
At the time of installation, the relay should be inspected for tarnished contacts, loose screws, or
other imperfections.
If any trouble is found, it should be corrected in the manner described in the
section on SERVICING.
CAUT ION
Every circuit in the drawout case has an auxiliary brush.
It is especially important on current cir
cuits and other circuits with shorting bars that the auxiliary brush be bent high enough to engage the
connecting plug or test plug before the main brushes do.
This will prevent CT secondary circuits from
being opened.
Refer to Fig. 19.
OPERATION
Before the relay is put into service, it should be given a check to determine that factory adjustments
have not been disturbed. The time dial will be set at zero before the relay leaves the factory.
If the
setting has not been changed, it will be necessary to change this setting in order to open the time over
current unit contacts.
The following tests are suggested:
TARGET AND SEAL-IN UNITS
1.
Make sure that the tap screw is in the desired tap.
2.
Perform pickup and dropout tests as outlined in the ACCEPTANCE TESTS section.
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