Westinghouse KA Installation, Operation & Maintenance Instructions Manual

INSTRUCTIONS
TYPE K.A CARRIER .AUXILIARY RELAY
CAUTION
Before putting relays into service, remove
all blocking which may have been inserted for the
purpose of securing the parts during shipment, make
sure that all, moving parts operate freely, inspect the
contacts to see that they are clean and close proper­
ly, and operate the relay to check the settings and
electrical connections.
A P PL ICAT ION
KA
The type relay is an auxiliary relay u sed in
the distance carrier relaying
prevent instantaneous tripping for faults e xternal to
the line section to which it is applied, and to permit
instantaneous simultaneous
faults. The relay is arranged to respond to indica­
tions of fault power and direction provided by the
phase and ground relays, thereby controlling the trans­
mission of the carrier signals.
CONSTRUCT ION AND O PERAT ION
KA
The type relay consists of directional auxili­
ary units, receiver and alarm units, and a phase fault
carrier operation indicator.
relay contains a hi�h speed overcurrent unit used to
start carrier transmission for ground faults.
struction and operation of
scribed below. Complete details of the operation of
this relay in the distance carrier relaying scheme is
41-911.
described in I.L.
Overcurrent Unit
The overcurrent unit is a product induction cyl­
inder type unit. The time phase relationship of the
two air gap fluxes necessary for the development of
torque is achieved by means of a capacitor connected
in series with one pair of pole windings.
Mechanically, the overcurrent unit is composed of
fotr basic components: a die-cast aluminum frame,
an electromagnet, a moving element assembly, and a
molded bridge.
The frame serves as the mounting structure for
the magnetic core. The magnetic core which houses
NEW INFORMAT ION
INSTALLATION
scheme to block
tripping for internal
KA
In addition, the type
The con­
the relay units are de­
•
OPERATION
the lower pin bearing is secured to the frame by a
The bearing can be replaced, if neces­
locking nut.
sary, without having to remove the magnetic core
from the frame.
The electromagnet has two pairs of coils.
coils of each pair are mounted diametrically opposite
one another. In addition, there are two locating pins.
The locating pins are used to accurately position the
lower pin bearing, which is mounted on the frame,
with respect to
or
threaded into the bridge.
cured to the frame by four mounting screws.
The moving element
spiral spring, contact
aluminum cylinder assembled to a molded hub which
holds the shaft.
bottom jewel bearings.
bottom pin bearing and the upper pin bearing with the
cylinder rotating in an air gap formed by the electro ­
magnet and the magnetic core.
The bridge is secured to the electromagnet and
frame by two mounting screws.
the upper pin bearing, the bridge is used for mounting
the adjustable stationary
stationary contact housing is held in position by a
spring type clamp.
the underside of the bridge and is attached to the
moving contact arm by a spiral 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
spring out to the spring adjuster clamp.
When the current in the overcurrent unit exceeds
the pick-up value the contacts open, allowing positive
potential to be applied to the carrier transmitter.
A
transformer and varistor assembly is used in
conjunction with the overcurrent unit.
former is of the sati.D'ating type
energy to the overcment unit and reduces the burden
EFFECT I V E NOVEMBER
41-923.2
I.L.
•
MAINTENANCE
the upper pin bearing,
The electromagnet is se­
assembly consists
carrying member,
The shaft has removable top and
The shaft rides between the
In addition to holding
contact housing.
The spring adjuster is located on
The spring
contact, through the spiral
The trans­
which limits the
The
which is
of a
and an
The
1959