19
Indirect releases - secondary shunt
release (dual trip) (52T1) or undervoltage
(27.0)
The indirect release provides for the
conversion of modest control signals into
powerful mechanical-energy impulses. It is
primarily used to open medium-voltage
circuit breakers while functioning as a
secondary shunt-release (dual trip) or
undervoltage device.
These releases are mechanical energy-storage
devices. Their internal springs are charged as
a consequence of the circuit breaker
mechanism operation. This energy is released
upon application or removal (as appropriate)
of applicable control voltages (refer to Figure
12: Construction of secondary shunt release
(shown charged), Figure 13: Latch details
(shown charged) and Figure 14:
Undervoltage lock/operate selection on page
20).
The secondary shunt-release and
undervoltage release mounts to the
immediate left of the trip coil (54.1).
Secondary shunt-release (52T1) (refer to
Figure 12: Construction of secondary
shunt release (shown charged))
A secondary shunt-release (extra-trip coil)
(3AX1101) is used for electrical opening of
the circuit breaker by protective relays or
manual control devices when more than one
trip coil is required. The second trip coil is
generally connected to a separate auxiliary
supply (dc or ac) from the control supply used
for the normal trip coil.
The power requirement for the second trip
coil is approximately 70 W (for dc power) or
50 VA (for ac power).
Undervoltage release (27.0) (refer to
Figure 13: Latch details (shown charged)
and Figure 14: Undervoltage lock/operate
selection on page 20)
The undervoltage release (3AX1103) is used
for continuous monitoring of the tripping
supply voltage. If this supply voltage falls
excessively, the undervoltage release will
provide for automatic tripping of the circuit
breaker.
The undervoltage device may be used for
manual or relay tripping by employing a
contact in series with undervoltage device
holding coil. Relay tripping may also be
achieved by employing a normally open
contact in parallel with the holding coil.
Figure 12: Construction of secondary shunt release (shown charged)
23.0
13.0
9.0
15.0
5.0
3.0
11.0
21.0
25.0 27.0
7.0
31.0
33.0
1.0
Figure 13: Latch details
(shown charged)
23.0
25.0
29.0
21.0
27.0
Locked/unlocked selection screw (undervoltage release only)
Item
Description
1.0
Magnet core
3.0
Housing
5.0
Mounting holes
7.0
Magnet coil
9.0
Magnet armature
11.0
Tension spring
13.0
Adjusting screw
(factory set) for 11.0
15.0
Tripping pin
21.0
Locking pin
23.0
Striker pin
25.0
Latch
27.0
Spring
31.0
Striker-pin spring
33.0
Terminal block
Item
Description
21.0
Locking pin
23.0
Striker pin
25.0
Latch
27.0
Spring
29.0
Locked/unlocked selection screw
The power requirement for the undervoltage
device is approximately 20 W (for dc power)
or 20 VA (for ac power).
If this scheme is used, a resistor must be
provided to limit current when the normally
open contact is closed.
Secondary shunt and undervoltage releases
are available for all standard ANSI/IEEE control
voltages.
Содержание 3AH35-SE Series
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