Basic Structure Of The Circuit-Breaker; On Withdrawable Part; Function; Function Of The Circuit-Breaker Operating - ABB VM1 Instruction Manual

2.3 Basic structure of the circuit-breaker on
withdrawable part
(Figures 9/9 to 9/12, 9/19 and 9/24)
The withdrawable part, which can be moved
manually or by a motor if fitted, consists of a steel
sheet structure on which the circuit-breaker with its
ancillary components is mounted.
Insulated contact arms 34 with the spring-loaded
contact systems 34.1 are fitted to the circuit-
breaker poles.
connection to the panel when the withdrawable
part is inserted into the service position.
A multi-pole control wiring plug connector 36
connects the signalling, protection and control
wiring between the panel and the withdrawable part.
The withdrawable assembly and the circuit-breaker
are connected via a multi-pole control wiring plug
connector 37.
As soon as the withdrawable part 31 has been slid
into the panel and its base frame has engaged in
the test/disconnected position, it is positively
connected to the panel. At the same time, it is
earthed by its travel rollers in their rails. The
magnetic actuator mechanism of the circuit-
breaker, including its controls and indicators, is
accessible at the front of the withdrawable part.
Withdrawable parts of the same version are
interchangable. With the same dimensions but dif-
ferent circuit-breaker equipment, coding of the
control wiring
combinations of withdrawable parts and panels
(see figure 9/17).

Function

3
3.1

Function of the circuit-breaker operating

mechanism

3.1.1 Magnetic actuator

(Figure 9/14)
The actuator is the heart of the circuit-breaker
operating mechanism. It combines the following
integrated functions:
• latching in the limit positions,
• release,
• switching.
The actuator is a bistable permanent magnet
system in which the armature motion is effected by
activating the ON or OFF coil. In the limit positions,
the armature is held in place magnetically by the
field of two permanent magnets. Release of a
switching operation is effected by exciting one of
the two coils until the latching force of the perma-
nent magnets is exceeded temporarily.

3.1.2 Opening and closing procedure

(Figures 9/13 to 9/14)
The opening and closing processes can be remote
controlled by applying a voltage to input -Y3 (ON)
These create the electrical
plug prevents impermissible
and -Y2 (OFF) (see also sections 10.1.1a and 6.2).
The breaker can be operated locally by pressing
push-buttons 3 and 4.
In the closing process, the armature motion acts
direct via lever shaft 18 on the moving contact 24.1
until the contacts meet.
In the further motion sequence, the pretensioned
spring arrangement 20 is tensioned to 100% and
the necessary contact force thus applied. The
available overtravel is greater than the maximum
contact burn-off throughout the life of the vacuum
interrupter.
3.1.3 Reclosing sequence
The operating
prepared for reclosing, and with the short
recharging time of the storage capacitor (max. 3 s)
it is also suitable for multi-shot reclosing.

3.1.4 Circuit-breaker controller

The control module is available as a standard
version and as a full version.

3.1.4.1Function of the standard version

All the conditions for control of the opening and
closing commands to the magnetic actuator are
defined in a microprocessor:
• Supply voltage must be applied to the AC/DC
converter.
• The storage capacitor must be sufficiently
charged for the next switching operation:
Switch position
OFF
ON
• The closing coil can only be activated when the
breaker is OFF.
• Closing is disabled when an opening command
is simultaneously active.
• Deactivation of the opening or closing coil takes
place when the relevant limit position has been
reached.
If the ON limit position is not reached within 70 ms
during a closing operation, an opening operation is
immediately initiated so as to ensure a defined
switch position in all cases.
• The anti-pumping system ensures that only one
ON-OFF operation is performed when a closing
command is active and followed by an opening
command. The active closing command must
be cancelled and reset for the next closing
operation.
• Activation of the closing coil (-Y1) can be
blocked by an external blocking signal.
mechanism is fundamentally
Storage capacitor
energy for:
ON and OFF
OFF
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