34
Types SDV-R and SDV-R-AR distribution circuit breakers |
Instruction manual
Item
Description
23.0
Striker pin
29.0
Locked/unlocked
selection screw
Position A: locked
Position B: unlocked
(operating position)
Cancel the lock for the undervoltage release by shifting
the locking screw (29.0) from A to B.
A
B
A
B
23.0
23.0
Figure 21: Undervoltage lock/operate selection
Construction and mode of operation of
secondary shunt-release and
undervoltage release
The release consists of a spring-power
stored-energy mechanism, a latching device
and an electromagnet. Refer to Figure 19:
Construction of secondary shunt release
(shown charged) and Figure 20: Latch
details (shown charged) on page 33 and
Figure 21: Undervoltage lock/operate
selection.
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), pivoted in the cover
sheets of the magnet armature (9.0).
The armature (9.0) is pivoted 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 secondary
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. When
this happens, the latch (25.0) loses its
support and releases the striker pin (23.0)
that is forced out by the spring (31.0).
On the undervoltage release 3AX1103, the
latch (25.0) is held by the locking pin (21.0)
as long as the armature (9.0) is energized. If
the circuit of the magnet coil (7.0) is
interrupted, the armature (9.0) drops off,
thus causing the latch (25.0) to lose its
support and release the striker pin (23.0).
Following every tripping operation, the
striker pin (23.0) must be reset to its normal
position by loading the spring (31.0). This
takes place automatically via the operating
mechanism of the circuit breaker.
Since the striker pin of the undervoltage
release 3AX1103 is latched only when the
armature is energized, the undervoltage
release is provided with a screw (29.0), for
locking the striker pin (23.0) in the normal
position for adjusting purposes or for
carrying out trial operations during circuit
breaker servicing. Position A (locked)
disables the undervoltage release. Position B
(unlocked) is the normal operating position.
29.0
29.0
