Structure And Function; Structure Of The Breaker Poles; Structure Of The Breaker Operating; Releases, Blocking Magnet - ABB VD4 Instruction Manual

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Structure and function

3.1

Structure of the breaker poles

(Figures 3/1, 3/2 , 3/6, 3/7 and 3/8)
The 36 kV and 40.5 kV circuit-breakers of type
VD4 are designed as withdrawable units. The
poles, which are constructed in column form, are
mounted on a torsionally rigid enclosure sub-
structure with rollers. The live parts of the breaker
poles are located in the insulating material
pole tubes and protected from impacts and other
external influences.
With the breaker closed, the current path leads
from the upper contact arm 57.1 and a chamber
holder fixed in the pole tube to the fixed contact
58.2 in the vacuum interrupter 58, then via
the moving contact 58.3 and roller contact to
the lower contact arm 57.2. The switching motion
is effected by means of the insulated coupling
rod with internal contact force springs.
3.2 Structure of the breaker operating mechanism
(Figures 3/3, 3/4, 3/7, 6/1 to 6/5, 7/5 to 7/8)
The operating mechanism located in the housing
substructure 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 storage mechanism.
The stored-energy spring mechanism essentially
consists of drum 55.33 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.
The operating mechanism is fundamentally suitable
for autoreclosing and, due to the short charging
times, also for multi-shot autoreclosing.
The operating mechanism is normally fitted with
a charging motor. There is also a facility for
charging the stored energy spring manually.
There is one rating plate 55.7 with the main data
of the switch equipment on front cover plate left
hand side 50.7, and another on breaker
mechanism housing.
The basic version of the stored-energy spring
mechnism is fitted with the following auxiliary
equipment:
Shunt release OFF Y2
●
Shunt release ON Y3
●
Blocking magnet Y1 with auxiliary switch S2
●
Five-pole auxiliary switches S3 and S4
●
ON-OFF operating shaft 54
●
Mechanical switch position indicator 55.4
●
Charging condition indicator 55.8 for the stored
●
energy spring
Mechanical operating cycle counter 55.5.
●
Motor charging mechanism
●
Five-pole auxiliary switch S1 to switch the
●
charging motor
Anti-pumping relay K0.
●
The following additional equipment can
be installed:
Blocking magnet Y0 on the withdrawable part
●
Second shunt release OFF Y9
●
Indirect overcurrent release Y7
●
Auxiliary switch S7 for electrical opening
●
signalling
Undervoltage release Y4
●
Five-pole auxiliary switch S5
●
3.2.1 Releases, blocking magnet and auxiliary switches
(Figures 2/4 to 2/6, 3/3, 6/2, 7/7 and 7/8)
The releases and the blocking magnet
are mounted at the bottom of the stored-energy
spring mechanism.
The allocation of the auxiliary switches can be
seen in the wiring diagram of figure 2/4.
The five-pole auxiliary switch S1 is operated by
the charging condition indicator 55.8. It controls
the charging motor M1, serves as an electrical
interlock for shunt release ON Y3 when the
spring energy storage 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 optional
blocking magnet Y1 with the circuit-breaker in
the closed position. There is one further NOC
for other purposes.
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.
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