I.L. 41-933.3
The type KV-1 undervoltage relay has a dropout range of
80
to
100
volts a-c with a continuous rating of
132
volts.
The dropout time characteristics for the undervoltage unit is
shown in Figu�e
2.
Circuit
The main contacts will safely close
30
amperes at
250
volts d-e
and the seal-in contacts of the indicating contactor switch
will safely carry this current long enough to trip a circuit
breaker.
The indicating contactor switch has a pickup of approximately
1
ampere.
Its d-e resistance is
0.1
ohms.
The moving contact assembly has been factory adjusted for low
contact bounce performance and should not be changed.
The set screw in each stationary contact has been shop adjusted
for optimum follow and this adjustment should not be disturbed.
SETTINGS
The relay as received has been factory adjusted for
100
volt
dropout.
Any other dropout voltage over the range can be gotten by
varying the tension of the spiral spring attached to the moving
element assembly.
Apply the desired dropout voltage and vary
the spring
tension by
placing a screwdriver or similar tool
into one of the notches located on the periphery of the spring
adjuster and rotating it.
Increased accuracy can be obtained
by pre-heating the relay at normal
voltage for approximately
one hour before making an adjustment.
INSTALLATION
The relays should be mounted on switchboard panels or their
equivalent in a location free from dirt, moisture, excessive
vibration, and heat.
Mount the relay vertically by means of the
four mounting holes on the flange for semi-flush mounting or by
-3-
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