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Type COV Voltage
Controlled Overcurrent Relay
For double trip relays, the upper stationary contact is
adjusted such that the contact spring rests solidly
against the back stop. The lower stationary contact is
then adjusted such that both stationary contacts
make contact simultaneously with their respective
moving contact.
4.2
INDICATING CONTACTOR SWITCH (ICS)
The only setting required on the ICS unit is the selec-
tion of the 0.2 or 2.0 ampere tap setting.
4.3
INDICATING INSTANTANEOUS TRIP (IIT)
The core screw must be adjusted to the value of pick-
up desired.
The nameplate data will furnish the actual current
range that may be obtained from IIT unit.
4.4
VOLTAGE UNIT (V)
The voltage unit spring calibration is set to close its
contact when the applied voltage is reduced to 80
volts. The voltage unit can be set close its contacts
from 80 volts to 100 volts by adjusting the resistor
located at the rear of the voltage unit. The spiral
spring is not disturbed when making any settings
other than the calibrated setting of 80 volts.
5.0 INSTALLATION
The relays should be mounted on switchboard pan-
els or their equivalent in a location free from dirt,
moisture, excessive vibration and heat. Mount the
relay vertically by means of the rear mounting stud or
studs for the type FT projection case or by means of
the four mounting holes on the flange for the semi-
flush type FT case. Either the stud or the mounting
screws may be utilized for grounding the relay. Exter-
nal toothed washers are provided for use in the loca-
tions shown on the outline and drilling plan to
facilitate making a good electrical connection
between the relay case, its mounting screws or
studs, and the relay panel. Ground wires should be
affixed to the mounting screws or studs as required
for poorly grounded or insulating panels. Other elec-
trical connections may be made directly to the termi-
nals by means of screws for steel panel mounting or
to the terminal stud furnished with the relay for thick
panel mounting. The terminal stud may be easily
removed or inserted by locking two nuts on the stud
and then turning the proper nut with a wrench.
For detail information on the FT case refer to Instruc-
tion Leaflet 41-076.
6.0 ADJUSTMENTS AND
MAINTENANCE
The proper adjustments to insure correct operation of
this relay have been made at the factory. Upon
receipt of the relay, no customer adjustments, other
than those covered under "SETTINGS", should be
required.
The indicating Instantaneous Trip unit (IIT) used in
some relays requires a much higher current for trip-
ping than is required by the other units. For this rea-
son, the junction of the CO unit coil and the IIT unit
coil is brought out to switch jaw no. 3 (whenever it is
available) to permit the testing of these units sepa-
rately.
!
CAUTION
When applying current in excess of 50 amperes
to the test IIT, the current should not be left on
while adjusting it to the trip level. Instead, apply
the current in short burst, not more than 2 sec-
onds long, to check for tripping. Make adjust-
ments in the current control while the current is
off.
High currents left on for excessive time periods can
result in the softening and possible melting of insula-
tion on the interconnecting wires.
6.1
ACCEPTANCE CHECK
The following check is recommended to insure that
the relay is in proper working order:
6.1.1. Overcurrent Unit (CO)
The directional unit contacts must be in the closed
position when checking the operation of the overcur-
rent unit.
A. Contact
By turning the time dial, move the moving con-
tacts until they deflect the stationary contact to a
position where the stationary contact is resting
against its backstop. The index mark located on
the movement frame should coincide with the "O"
mark on the time dial. For double trip relays, the
follow on the stationary contacts should be
approximately 1/64".
For relays identified with a "T", located at lower
left of stationary contact block, the index mark on
the movement frame will coincide with the "O"
mark on the time dial when the stationary con-
41-116K
5
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