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KLF Loss-of-Field Relay
2)
Sensitivity Adjustment
a) Apply voltage to terminals 4 and 5. With the
adjustable resistor, Rv, which is located at
the upper left-hand corner, set for maximum
resistance (2500 ohms) adjust the spring so
that contacts make (to the left) at 70 volts.
The contacts should open when unit is ener-
gized with 71 or more volts.
b) Relay is shipped with 80 volts setting. This is
accomplished by lowering resistance value
of R
until contacts make at 80 volts and
V
open when unit is energized with 81 or more
volts. The spring should not be used for this
setting.
F. 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 settings (0.2 or 2.0) being
used. The indicator target should drop freely.
G. Telephone Relay
Energize the telephone circuit, terminals 10 and 3,
with rated dc voltage. The telephone relay (X) should
operate positively. With an air gap of .003" – .004"
the contacts should close in 167 to 250 ms when the
telephone relay coil is shorted. This may be done by
manually closing the impedance unit (Z) and direc-
tional unit (D) contacts.
H. Compensator Check
Accuracy of the mutual impedance T of the compen-
sators is set within very close tolerances at factory
and should not change under normal conditions. The
mutual impedance of the compensators can be
checked with accurate instruments by the procedure
outlined below.
1. Set T
on the 15.8 tap
A
T
on the 5.1 tap
C
2. Disconnect the L-leads of sections M
M
C
3. Pass 10 amperes ac current in terminal 9
and out of terminal 8.
4. Measure the compensator voltage with an
accurate high resistance voltmeter (5000
ohms/volt).
5. Compensator A voltage should be checked
between lead L
A
For T
= 15.8 the voltage measured should
A
be 237 volts (±3%).
6. Compensator C voltage should be checked
between lead L
the resistor which is mounted in the rear.
For T
= 5.1, the voltage should be 76.5
C
volts (±3%).
7. For all other taps the compensator voltage is
1.5 IT (±3%)
where I – relay current
T – tap setting
9.0 RENEWAL PARTS
Repair work can be done most satisfactorily at the
factory. However, interchangeable parts can be fur-
nished to the customers who are equipped for doing
repair work. When ordering parts, always give the
complete nameplate data.
41-748P
A
terminal 5.
and the fixed terminal on
C
and
19
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