Siemens vacuum circuit breaker 38-3AH3 38 kV - Manual (Page 28)

Vacuum interrupter/
operator
Figure 21: Operator sequential operation diagram
Closed
voltage applied.
Undervoltage device
27 picks up. Spring-charge motor
(88.0) energized.
L3 opens in series
with anti-pump relay
(52Y). LS21 and LS22
operate to de-
energize spring-
charging motor. LS4 closes to signal
closing spring is
charged. LS9 closes close
circuit only when
closing spring is fully
charged.
Closing spring is fully
charged.
No action! Open 52b
in series with close
coil (52SRC) blocks
closing spring-
release. Close coil is actuated
through the closed
52b contacts and the
two normally closed
contacts of the anti-
pump relay (52Y).
Closing
command
when
circuit
breaker is
closed. circuit
breaker is
open.
No action! Anti-
pump relay (52Y)
picks up through the
closed LS3 contact
and opens.
closing
spring is not
charged.
The closing spring is
unlatched. The opening spring
is charged.
Circuit breaker
auxiliary contacts
52a and 52b change
state. The circuit breaker
closes. LS21 and LS22 close
to energize motor
(88). LS3 closes and
LS4 opens to cancel
closing spring signal. 52a contacts in
series with the trip
coil (52T) close to
enable a trip
opertion.
Continuous
closing command.
Close coil (52SRC)
unlatches the closing
spring and the circuit
breaker closes.
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 anti-pump relay
(52Y) opens two
contacts in series
with the close coil
(52SRC).
The close coil
(52SRC) is now
blocked and cannot
be activated until
springs are fully-
charged and close
command is
removed.
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.
Closing
Tripping
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.
Trip
command.
Trip coil (52T) can
only be activated
when in series
connected 52a
contact is closed. Undervoltage device (27) is
activated by opening a NC
contact in series with 27 or by
loss or reduction of tripping
voltage.
1
Secondary shunt-
release (dual-trip)
function activated by
remote trip
command contact
NO.
1
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.
Secondary release
unlatches the
opening spring.
1
Trip coil (52T)
unlatches the
opening spring.
Footnote:
1 Optional items.
28