Advertisement
B.
Indicating Contactor Switch Unit (ICS)
The indicating contactor switch is a small d-e
operated clapper type device. A magnetic ar�ature,
to whicb leaf-spring mounted contacts are attached,
is attracted to the magnetic core upon energization
of the switch. When the switch closes, the moving
contacts bridge two stationary contacts, completing
the
trip
circuit.
Also
fingers on the armature deflect a spring located on
the front of the switch, which allows the operation
indicator target to drop. The target is reset from the
outside of the case by a push r od located at the
bottom of the cover.
The front spring, in addition to holding the target,
provides restraint for the armature and thus c ontrols
the pickup value of the switch.
C. Telephone- Type Relay
The X3 relay is a telephone type relay with slow
drop-out characteristics. A solenoid attracts an iron
right-angle bracket which in turn operates a set of
break and make contacts. Dropout delay is obtained
by the air gap and adjustment between the solenoid
core and the armature, and the copper slug on the
core. A dropping resistor is connected in series with
the X3 relay for 250 V.D.C.
D.
Three Phase Negative Sequence Filter
The
filter
consists
each with three windings connected as shown in Dwg.
17-D-3325. With unbalanced three-phase currents flow
ing in the input terminals, the output voltage and
current will be proportional to the negative seque nee
components of the unbalanced input.
CHARACTERISTICS
0
The type KQS relay is an auxiliary relay used in
the
carrier relaying scheme with the types KDIO,
KRD-4, & KA-4 relays.
The minimum pick-up of the type KQS relay is 1
ampere and the maximum 3Ioampe res is 100 amperes.
This is the total phase current passed through
the filter and relay to neutral with the other two
phase currents zero. The correspond ing negative and
zero sequence values are each one third of the val
ues given above.
2
dur ing
this operation two
of
three
mutual
reactors
The negative sequence coils of the type KQS re
lay are normally connected in star to terminals A',
B', and C' of the negative sequence filter. The neu
tral of this star should not be grounded. The term
inals A", B" , and C" should be connected together
to the neutral of the main current transformers. It is
important that no other elements be connected be
tween A", B" and C" and the star or neutral point.
The alternate connection is used where other
equipment must be connected between A", B" and
C" and the neutral point. In this case the negative
sequence
coils
are
connected between
A'A", B'B" and C'C". With this connection zero
sequence current must be eliminated or by-passed
around the filter. Delta current is not satisfactory be
cause it causes an undesirable phase shift in the
filter.
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 vert ically by means of the four mounting holes
on the flange for semi-flush m ounting or by means of
the rear mounting stud or studs for projection mount
ing. Either a mounting stud or the mounting screws
may be utilized for grounding the relay.
trical connections may be made directly to the term
inals by means of screws for steel panel mounting or
to the terminal studs furnished with the relay for
thick panel mounting. The terminal studs may be
easily removed or inserted by locking two nuts on the
stud and then turning the proper nut with a wrench.
For detailed FT case information refer to I.L.
41-076.
ADJUST MENTS AND MAINT ENANCE
The proper adjustments to insure correct oper�
tion of this relay have been made at the factory and
should not be disturbed after receipt by the customer.
If the adjustments have been changed,
taken apart for repairs or if it is desired to check
the adjustments at regular maintenance periods, the
instructions below should be followed.
All contacts should be periodically cleaned. A
contact burnisher Stt182A836H01 is recommended for
this purpose. The use of abrasive material for clean-
terminals
The elec
the relay
Advertisement
