Tripping - Westinghouse DBN-1016 Technical Manual

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CHAPTER 2-PRINCIPLES OF OPERATION
closing coil. When the closing coil is ener-
gized the plunger push rod in the closing sole-
noid rises to close the circuit breaker.
2-1-1-3 Tripping
Tripping of the circuit breaker can be ac-
complished by means of the manual button, the
shunt trip device, or the overcurrent trip unit.
To trip the circuit breaker manually, de-
press button as indicated on the face plate.
When released, the button will return to its
normal position.
To trip the circuit breaker electrically,
turn the control switch, which is remotely lo-
cated, to the "TRIP" position in order to en-
ergize the shunt trip coil. With this trip coil
circuit closed, the shunt trip device will oper-
ate to rotate the trip bar and trip the circuit
breaker.
The overcurrent trip unit will also cause
the circuit breaker to open by direct action on
the trip bar whenever the current exceeds the
designated pickup values.
2-1-1-4 EI_leal Operation
Figure 2-1-1 shows the wiring diagram and
the schematic diagram for an electrically oper-
ated circuit breaker. When the close switch
(CSC) is closed, the closing relay is actuated
which closes contacts xa to energize the clos-
ing solenoid. The closing solenoid closes the
breaker as described in Chapter 1, Section 2.
When the breaker is closed the normally open
circuit breaker contact "an closes to set up
the
shunt trip circuit. Closing the circuit breaker
trip switch (CST) energizes the trip coil to
trip the circuit breaker as described in Chap-
ter 1, Section 2.
This figure also includes a schematic dia-
gram of the indicating light circuit. The white
lamp is energized whenever control power is
available. When the circuit breaker is closed,
auxiliary contact "a" closes to energize the
blue indicating lamp. These indicating lamps
provide a convenient means of observing the
operating state of the circuit breaker.
@SHUNT TRIP
~ AUXILIARY SWITCH
b NORMALLY CLOSED
CONTACT
@CLOSE COIL
1.
CLOSING RELAY
o
CLOSING RELAY
:ll<o
BLOWOUT COIL
e
UNDERVOLTAGE TRIP
l AND CONTACT
o
WHITE LIGHT·
STATIONARY
r._COMPONENT
TERMINAL
o
BLUE LIGHT
-Y-MAIN DISCONNECTS
8
TERMINAL BLOCK
CONNECnON
INTERRUPTING
) _ CONTACTS OF
MOVABLE
COMPONENT
..LCS CONTROL SWITCH -
TC CLOSE
k
OVERCURRENT TRIP
..LCS CONTROL SWITCH -
-DEVICE
TT TRIP
6
~
SECONDARY
'V DISCONNECTS
OJ
FULL WAVE
.2.
AUXILIARY SWITCH
SILICON
CO
NORMALLY OPEN
RECnFIER
CONTACT
FIGURE
2./ .. 2 -
Schematic Symbol.
2·3