Siemens 3AH3 Instruction Manual page 26

Position A: locked (disabled)
Position B: unlocked (enabled) (operating position)
Item Description
23.0 Striker pin
Undervoltage
enable/
29.0
disable
setting screw
Cancel the lock for the undervoltage release by shifting the locking screw (29.0)
from A (disable) to B (enable).
Figure 17: Undervoltage lock/operate selection
120 or 240 Vac
supply
Figure 18: Capacitor-trip device
26
A
23.0
B
A
23.0
B
01
T
SD5
24
52a
23
A1
(+)
52T
1
(-)
A2
34
2
52a
(+)
33
(-)
Capacitor trip
Construction and mode of operation of
secondary shunt-release and
undervoltage release (refer to Figures 15,
16 and 17)
The release consists of a spring-power
stored-energy mechanism, a latching device
29.0
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
29.0 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
Capacitor
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
Resistor
interrupted, the armature (9.0) drops off,
thus causing the latch (25.0) to lose its
support and release the striker pin (23.0).
Rectifier
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.