TYPE KQS PHASE SELECTOR RELAY
able stationary contacts. The bridging moving con
tact should touch both stationary contacts simul
taneously.
Three-Phase Negative Sequence Filter
The filter is adjusted for balance at the factory
and no further adjustments or maintenance should be
required. With balanced three phase currents of 10
amperes. 60 cycles, phase rotation A. B. C. intro
duced into the input terminals as marked on Dwg.
17-D-3325. The voltage between the output terminals
A'. B'. and C '. should be zero. Use a high resistance
voltmeter for this check.
Connect terminals A', B', and C', to terminals
3. 5. and 7 of the type KQS relay. Connect the relay
terminals 2. 4. and 6 together. With balanced three
phase currents of 5 amperes, 60 cycles, phase rota
tion A, B, C, applied to the filter input terminals A,
B. C. and the neutral made by connecting terminals
A", B" and C" together, the voltage across the re
lay terminals 2 and 3. 4 and 5 and 6 and 7 should be
zero. Now, reverse the connections to the filter in-
4
put terminals A and B and check the voltage now
appearing across the relay terminals. These three
voltages should be substantially 0. 7 volt.
With the relay and filter connected, apply 1 am
pere between phase to neutral of the filter. Adjust
the spring of the proper phase selector such that the
contact just closes.
Apply 15 amperes between phase to neutral and
check the action of the phase selector elements. The
element associated with the phase being energized
should operate while the other two elements should
remain open.
RENEWAL PARTS
Repair work can be done most satisfactorily at
the factory. However. interchangeable parts can be
furnished to the customers who are equipped for do
ing repair work. When ordering parts, always give
the complete nameplate data.
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