ABB VD4 Series Operating Manual - page 12
12
• Mechanical OFF push-button 3
• Mechanical position indicator 4
• Charging condition indicator 8 for the
spring energy store
• Mechanical operating cycle counter 5
The following additional equipment can be installed:
• Blocking magnet -Y1 with auxiliary switch -S2
• Shunt release ON -Y3
• Second shunt release OFF -Y9
• Indirect overcurrent release -Y7
• Undervoltage release -Y4
• Five-pole auxiliary switches -S3 and -S5
• Charging motor -M0
• Five-pole auxiliary switch -S1 to switch the
charging motor.
3.2.1
Releases, blocking magnet and auxiliary switches
(Figures 3/1, 3/5, 7/1, 7/2, 7/3 and 7/5)
• The releases and the blocking magnet are
mounted at the top left on the spring operating
mechanism.
• The allocation of the auxiliary switches can be
seen in the wiring diagram of figure 7/5.
• The five-pole auxiliary switch -S1 is operated by
the charging condition indicator 8. It controls
the charging motor -M0, serves as an electrical
interlock for shunt release ON -Y3 when the
spring mechanism is not sufficiently charged,
and also provides an electrical switching
readiness signal.
• Operation of the five-pole auxiliary switches
-S3, -S4 and -S5 is dependent on the switching
position of the circuit-breaker.
• Auxiliary switch -S3 interrupts the circuit of the
optional additional shunt release OFF -Y9 with
the circuit-breaker in the open position, and the
circuits of shunt release ON -Y3 and the optio-
nal blocking magnet -Y1 with the circuit-break-
er in the closed position. There is one further
NOC for other purposes.
• On failure or absence of the control voltage,
blocking magnet -Y1 mechanically locks the ON
half shaft and simultaneously acts on the corre-
sponding auxiliary switch -S2 to interrupt the
circuit of shunt release ON -Y3.
• Blocking magnet -Y1 is accessible when front
plate 1.1 is removed.
• Auxiliary switch -S4 interrupts the circuit of shunt
release OFF -Y2 with the circuit-breaker in
the open position. One further NOC and three
NCCs are available for annunciation, control and
interlock purposes.
• Auxiliary switch -S5 can be optionally designed
with any possible combination of contacts from
3
Structure and function
3.1
Structure of the breaker poles
(Figures 2/2, 3/2, 3/3 and 3/4)
The poles, which are constructed in column form,
are mounted on the bracket-shaped rear part of
mechanism enclosure 1. The live parts of the brea-
ker poles are located in the insulating material pole
tubes 12 and protected from impacts and other
external influences.
With the breaker closed, the current path leads from
the upper breaker terminal 13 and a chamber holder
fixed in the pole tube to the fixed contact 15.2 in the
vacuum interrupter 15, then via the moving contact
15.3 and the roller contact 16.2, to the lower breaker
terminal 14. The switching motion is effected by
means of the insulated coupling rod 18 with internal
contact force springs 17.
The basic structure of a vacuum interrupter is
explained in figure 3/3.
3.2
Structure of the breaker operating mechanism
(Figures 3/1, 3/2, 3/4 and 3/5)
The operating mechanism is of the stored-energy
spring type and acts on the three breaker poles.
The necessary operating energy is stored ready for
activation by charging the spring energy store.
The stored-energy spring mechanism essentially
consists of drum 33 containing the spiral spring,
the charging system, the latching and operating
mechanism and the linkages which transmit the
force to the breaker poles. In addition, there are
supplementary components such as the charging
motor, releases, auxiliary switches and the controls
and instruments located on the front of the
mechanism enclosure 1.
The operating mechanism is fundamentally suitable
for auto-reclosing and, due to the short charging
times, also for multi-shot auto-reclosing.
The generator breaker have a built-in mechanical
delay system with which the opening time is
prolonged by approx. 30 ms.
In the basic version of the circuit-breaker, the
spring energy store is charged manually. The
operating mechanism can optionally be fitted with
a charging motor.
There is one rating plate with the main data of the
switch equipment on front plate 1.1, and another at
the lower front right in mechanism enclosure 1.
The
basic version
of the stored-energy spring
mechanism is fitted with the following auxiliary
equipment:
• Shunt release OFF -Y2
• Five-pole auxiliary switch -S4 for
annunciation purposes
• Auxiliary switch -S7 for fault annunciation
• Mechanical ON push-button 2