Westinghouse KQS Instructions Manual

Before p utting rela y s into service, re­
CAUTION:
move all blocking which may have been inserted for
the purpose of securing the parts during shipment,
make sure that all moving parts operate freely, in­
spect the contacts to see that they are clean and
close properly, and operate the relay to check the
settings and electrical connections.

APPLICATION

The type KQS relay operates on negative and
zer o sequence currents to select the faulted phase
when a single phase-to-ground fault occurs on the
protected transmission line. The zero sequence cur­
rent is obtained from the neutral of the line current
transformers, and the negative sequence current from
an external three-phase
relay.
CONSTR UCTION AND OPERATION
The type KQS relay
three-phase negative
0
selector elements, a telephone type relay, and three
indicating contact or switches which are mounted in
the case.
A. Phase Selector E lements
The

phase selector element

duction cylinder type unit operating on the inter-
action between the
0
operating circuit flux. The operating circuit flux is
obtained from the output of the negative sequence
current filter and the polarizing circuit flux is ob­
tained from the zero sequence component of fault
current.
Mechanically, the phase selector element is com­
posed of four basic components: a die-cast aluminum
frame, an electromagnet, a moving element assembly,
and a molded bridge.
SUPERSEDES I.L. 41-928.18, dated March 1970
0 Denotes change from superseded issue.
Installation
INSTRUCTIONS
TYPE KQS PHASE SELECTOR RELAY FOR
SINGLE-POLE CARRIER RELAYING
filter supplied with the
consists of an external
sequence filter, three-phase
is a product in­
polarizing circuit flux and the
Westinghouse
OPERATION
•
The frame serves as the mounting structure for
the magnetic core. The magnetic core which houses
the lower pin bearing is secured to the frame by a
locking nut. The bearing can be replaced, if neces­
sary , without having to remove the magnetic core
from the frame.
The electromagnet
polarizing coils mounted diametrically opposite one
another; two series-connected operating coils mount­
ed diametrically opposite one another; two magnetic
adjusting plugs; upper and lower adjusting plug clips
and two locating pins. The locating pins are used
to accurately position the lower pin bearing, which
is m ounted on the frame, with respect to the upper
pin bearing, which is threaded into the bridge. The
electromagnet is secured to the frame by four mount­
ing screws.
The moving element
spiral spring, contact carrying member, and an alum­
inum cylinder assembled to a molded hub which holds
the shaft. The shaft has removable top and bottom
jewel bearings. The shaft rides between the bottom
pin bearing and the upper pin bearing with the cylin­
der rotating in an air gap formed by the electromagnet
and the magnetic core. The stops for the moving
element contact arm are an integral part of the
bridge.
The bridge is secured to the electromagnet and
frame by two mounting screws. In addition to hold­
ing the upper pin bearing, the bridge is used for
mounting the adjustable stationary contact housing.
The stationary contact housing is held in-position
by a spring type clamp. The spring adjuster is lo­
cated on the underside of the bridge and is attached
to the moving contact arm by a sprial spring.
spring adjuster is also held in place by a spring
type clamp.
With the contacts closed, the electrical connec­
tion is made through the stationary contact housing
clamp, to the moving contact,
spring out to the spring adjuster clamp.
EFFECTIVE NOVEMBER
I.L. 41-928.1C
MAINTENANCE
•
has two series-connected
assembly consists of
The
through the spiral
1976
a