TYPE KA CARRIER AUXILIARY RELAY
SHUNT
BALANCED AIK
�APS
UNBALAKCED AIR GAPS
POLAR UKIT
PERMAHEHT
MAGNET FLUX PATHS
183A062
Fig.
4.
Polar Unit Permanent Magnet Flux Paths.
and within the magnetic frame. RRT is the operating
coil and receives its energy from the local battery
when either CSP or CSG is closed. RRH is the hold
ing coil and receives its energy from the carrier
transmitted either from the local transmitter or the
one at the other end of the line section. These two
coils are connected to oppose each other with the
operating coil, RRT operating to close the RRP and
RRG contacts and trip; and the holding coil, RRH to
hold the RRP and RRG contacts open and block trip
ping. The restraining torque of the RRH coil
is
suf
ficient to overcome the operating torque of the RRT
coil. Consequently. RRP and RRG ccmtacts cannot
close as long as RRH is energized.
Alarm Unit
The alarm element is similar in construction to
the receiver element except that it is energized by a
single coil and operates a single set of contacts.
The coil is energized by the received carrier to close
the contacts and give an alarm. This element has a
higher-pick-up than that of the receiver element in
order to obtain a direct check on the sensitivity of
the tubes in the carrier transmitter-receiver.
The
failure of the alarm relay to pick-up when carrier is
4
started indicates insufficient output from the trans
mitter-receivers.
Operation lnd icator
The operation indicator gives a visual indication
of a carrier tripping operation for phase faults by the
distance relay through the RRP contacts.
For a
ground fault carrier relaying operation, the indicating
contactor switch (ICS) located in the ground relay
will drop a target.
CHARACTER IST ICS
The characteristics of the various elements of the
relays are
as
follows:
48V
12SV
250V
Avg.
Avg.
Avg.
Ohms
Ohms
Ohms
CSP or CSG Coil
27
27
27
CSP
&
CSG Tapped Resistor
200
600
1250
Carrier Resistor
2000
3750
19000
RRT Operating Coil
1100
1100
1100
RRT Coil Resistor
1320
5000
11200
RRH Holding Coil
1700
1700
1700
AL Alarm Coil
500
500
500
Operation Indicator (1 amp. )
0.1
0.1
0.1
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