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Vacuum interrupter/ operator – Siemens vacuum circuit breaker 38-3AH3 38 kV User Manual

Page 31

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Vacuum interrupter/
operator

Figure 25: Undervoltage lock/operate selection

Figure 26: Capacitor-trip device

23.0 - Striker pin

29.0 - Screw

Position A: locked

Position B: unlocked (operating position)

Cancel the lock for the undervoltage release by shifting the locking screw (29) from
A to B.

A

B

A

B

23.0

29.0

23.0

29.0

120 or 240 Vac
supply

01
T

24

23

52o

SD5

34

33

52o

A1

A2

52T

Capacitor trip

(+)

(-)

Rectifier

Resistor

(+)

(-)

1

2

Capacitor

Relay tripping may also be achieved by
employing a normally open contact in
parallel with the holding coil. If this
scheme is used, a resistor must be
provided to limit current when the
normally open contact is closed.

Secondary and undervoltage releases are
available for all standard ANSI/IEEE control
voltages.

Construction and mode of operation of
secondary
release and undervoltage
release

Refer to Figure 23: Construction of
secondary shunt release (shown charged)
and Figure 24: Latch details (shown
charged) on page 30 and Figure 25:
Undervoltage lock/operate selection on
page 31.

The release consists of a spring power-
storing mechanism, a latching device and
an electromagnet. These elements are
accommodated side-by-side in a housing
(3.0), with a detachable cover and three
through-holes (5.0) for fastening screws.
The supply leads for the trip coil are
connected to a terminal block (33.0).

The energy-storing mechanism consists of
the striker pin (23.0) and its operating
spring (31.0), which is mostly located
inside the striker pin (23.0). When the
spring is compressed, the striker pin is held
by a latch (25.0), whose sloping face is
forced against the appropriately shaped
striker pin (23.0) by spring (27.0). The
other end of the latch (25.0) is supported
by a partly-milled locking pin (21.0) (refer
to Figure 24: Latch details (shown
CHARGED) on page 30), that pivots in the
cover sheets of the magnet armature (9.0).
The armature (9.0) pivots in front of the
poles of the U-shaped magnet core, (1.0)
and is pulled away from it by the tension
spring (11.0).

If the magnet coil (7.0) of the shunt
release 3AX1101 is energized by a trip
signal, or if the tripping pin (15.0) is
mechanically actuated, magnet armature
(9.0) is swung against the pole faces.

31