T YP E KAB HIGH IMPEDA N C E
B US DIFF E R E N TIAL
The contact gap should be approximately .047"
between the bridging moving contact and the adjust
able stationary contacts. The bridging moving con
tact should touch both stationary contacts simultan
eously.
ROUT I NE MA I NT E NAN C E
All relays should be inspected periodic ally and
the operation should be checked at least once every
year or at such other time intervals as may be dic
tated by experience to be suitable to the particular
application.
All contacts should be periodically cleaned. A
contact burnisher S#18 2A836H01 is recommended for
this purpose. The use of abrasive material for clean
ing contacts is not recommended, because of the
danger of embedding small particles in the face of
the soft silver and thus impairing the contact.
Calibration
use the following procedure for calibrating the
relay if the relay has been taken apart for repairs or
the adjustments have been disturbed. This procedure
should not be used unless it is apparent that the
relay is not in proper working order. (See "Accept
ance Check").
Care should be used to avoid contact with the
capacitors since high voltages may be present with
the circuit energized.
Tuned Circuit
If the capacitors, reactor, or overvoltage unit
have been replaced, it may be necessary to retune
the circuit. This can be accomplished using a
regulated ac voltage with good sine wave. Initially
set the adjustable reactor screws about 1/z of their
total travel. The screws may be adjusted without
loosening the spring nuts.
*
Apply 75 volts ac to terminals 6 and 8 and
adjust either screw for maximum current as measured
by a milliammeter. This current should be less than
30 rna. The two screws should be positioned approxi
mately equal for the final adjustment.
After the above adjustment has been made it
may be necessary to re-adjust the overvoltage unit
spring for the desired operate voltage.
6
Overvoltage Unit (V)
1. The upper bearing screw should be screwed
down until there is approximately .0 25" clear
ance between it and the top of the shaft bearing.
The upper pin bearing should then be securely
locked in position with the lock nut.
2. The contact gap adjustment for the overcurrent
unit is made with the moving contact in the reset
position, i.e.,against the right side of the bridge.
Move in the left-hand stationary contact until it
just touches the moving contact. Then back off
the stationary contact one turn for a gap of
approximately . 030". The clamp holding the
stationary contact housing need not be loosened
for the adjustment since the clamp utilizes a
spring-type action in holding the stationary
contact in position.
3. The sensitivity adjustment is made by vary
ing the tension of the spiral spring attached to
the moving element assembly. The spring is
adjusted by placing a screwdriver or tool style
numb er 774B180G01 into one of the notches
located on the periphery of the spring adjuster
and rotating it. The spring adjuster is located
on the underside of the bridge and is held in
place by a spring type clamp that does not have
to be loosened prior to making the necessary
adjustments.
4. Apply the desired pickup voltage and adjust
the spring until the contacts just make. Voltages
above
250 volts ac RMS should not be applied
for more than 15 seconds at a time.
Overcurrent U nit (I T)
The stationary contacts should be set for 3/32"
contact gap. The bridging contact should make
simultaneously with both stationary contacts.
When the unit is energized above pickup current
the armature should seal in against the core and the
moving contacts should provide about 1/3 2'' contact
wipe.
I ndicating Contactor Switch (ICS)
The stationary contacts should be set for 3/64"
contact gap. The bridging contact should make
simultaneously with both stationary contacts.
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