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Siemens 38-3AH3 38 kV Instruction Manual page 28

Vacuum circuit breaker
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Figure 21: Operator sequential operation diagram
Closing
Closed
voltage applied.
Undervoltage device
Spring-charge motor
27 picks up.
(88.0) energized.
Closing spring is fully
charged.
LS21 and LS22
L3 opens in series
operate to de-
with anti-pump relay
(52Y).
energize spring-
charging motor.
circuit
breaker is
No action! Open 52b
closed.
in series with close
Closing
coil (52SRC) blocks
command
closing spring-
when
release.
No action! Anti-
pump relay (52Y)
picks up through the
closed LS3 contact
and opens.
52a contacts in
Circuit breaker
series with the trip
auxiliary contacts
coil (52T) close to
52a and 52b change
enable a trip
state.
opertion.
Rapid auto-reclosing. The closing spring is automatically recharged as described above.
Therefore, when the circuit breaker is closed both of its springs are charged. The closing spring
charges the opening spring during closing. As a result, the circuit breaker is capable of an
O-0.3s-CO-3 min-CO operating cycle. The dashed line shows the operating sequence initiated by
the closing command.
Tripping
Trip coil (52T) can
Undervoltage device (27) is
only be activated
activated by opening a NC
when in series
contact in series with 27 or by
connected 52a
loss or reduction of tripping
contact is closed.
voltage.
Trip coil (52T)
unlatches the
opening spring.
28
Vacuum interrupter/
operator
Anti-pumping feature (52Y) assures a continuously applied closing command does not
cause the circuit breaker to reclose automatically after it has tripped out on a fault.
LS4 closes to signal
closing spring is
charged.
circuit
breaker is
Close coil is actuated
open.
through the closed
52b contacts and the
two normally closed
contacts of the anti-
pump relay (52Y).
closing
spring is not
charged.
The closing spring is
unlatched.
The circuit breaker
closes.
Trip
command.
Undervoltage device (27) is activated
by closing NO contact, shorting the
27 coil. The NO contact is only
effective with the circuit breaker
closed. Resistor required.
1
Undervoltage device
27 unlatches the
opening spring.
1
Circuit breaker trips.
Continuous
closing command.
Close coil (52SRC)
unlatches the closing
LS9 closes close
spring and the circuit
circuit only when
breaker closes.
closing spring is fully
charged.
Motor cutoff
switches LS21, LS22
and LS3 are closed
because the closing
spring is discharged.
Before the spring-
charge motor has
recharged the
closing spring and
opened LS3, anti-
pump relay (52Y)
picks up and seals in.
The opening spring
is charged.
The anti-pump relay
(52Y) opens two
contacts in series
with the close coil
LS21 and LS22 close
(52SRC).
to energize motor
(88). LS3 closes and
LS4 opens to cancel
The close coil
closing spring signal.
(52SRC) is now
blocked and cannot
be activated until
springs are fully-
charged and close
command is
removed.
Secondary shunt-
release (dual-trip)
function activated by
remote trip
command contact
1
NO.
1
Secondary release
unlatches the
opening spring.
Footnote:
1
Optional items.
1

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