Function; Charging Of The Spring Energy Store; Closing Procedure; Opening Procedure - ABB VD4 Instruction Manual

Auxiliary switch S5 can be optionally designed
with any possible combination of contacts from
five NOCs to five NCCs. Its contacts are available
for any required control, annunciation or
interlock functions. The
normally configured as shown in figure 7/3.
The single pole auxiliary switch S7 (fleeting contact
time 30 ms) serves to provide a fault signal
("breaker released"). With remote control,
the auxiliary switch is necessarily operated via:
Shunt release OFF Y2 or
●
Shunt release OFF Y9 or
●
Undervoltage release Y4 or
●
Indirect overcurrent release Y7.
●
Note:
1. Shunt releases OFF (Y2) and ON (Y3)
are exclusively provided for opening and
closing in normal operation. For safety
breaking operations, the second shunt release
OFF (Y9) must be used, in most cases with
a separate control voltage supply.
These three releases are of the solenoid
type and suitable for a large number of
operating cycles.
2. The under voltage release (Y4) and/or
indirect over current release (Y7) are pure
safety and protection releases and must not
be used for switching in normal operation.
3.3

Function

3.3.1 Charging of the spring energy store

(Figures 3/3, 3/10, 6/2, 6/6, 7/7 and 7/8)
To provide the necessary motive energy, the spring
energy storage mechanism is charged via chain
55.34 fitted with ratchet wheel 55.35, either
automatically by a charging motor or by hand in
a vertical pumping action with charging lever
128. The current
shown at charging condition indicator 55.8
As a precondition for an autoreclosing sequence,
the operating mechanism is either (re-)charged
after a closing operation automatically by
the charging motor, or it requires (re-)charging by
hand if the operating mechanism is of the manual
type.

3.3.2 Closing procedure

(Figures 3/4, 3/6, 6/1, 6/3 and 7/7)
The closing process is initiated manually by
the double bit key 145 and the ON-OFF operating
shaft 54, or electrically by activation of shunt
release Y3. The release mechanism then permits
14
auxiliary switch
charging condition
drive shaft 55.30 to be rotated by the (previously)
charged spiral spring. The moving contact 58.3
in vacuum interrupter 58 is moved until the contacts
touch by cam disk and further kinematic links. In
is the further sequence of motion, spring
arrangement is tensioned and the appropriate
amount of contact force thus applied. The
available overtravel is higher than the maximum
value of contact erosion during lifetime of the
interrupter. During the closing process, opening
springs are simultaneously tensioned.

3.3.3 Opening procedure

(Figures 3/3, 3/6, 6/3 and 7/7)
The opening procedure is initiated manually by
the double bit key 145 and the ON-OFF operating
shaft 54, or electrically by activation of one
of the releases Y2, Y4, Y7 or Y9. Release
mechanism then permits drive shaft 55.30 to
be turned further by the spring energy
storage mechanism, which is still sufficiently
charged. The opening spring, which is thus
released, moves the contact 58.3 into the open
position at a defined speed.

3.3.4 Autoreclosing sequence

An OFF-ON or OFF-ON-OFF autoreclosing
sequence is activated and checked by the
protection system. It is necessary for the spiral
spring in the operating mechanism to be in
the (re-)charged condition, with the circuit-
breaker in the closed position. The (re-)charging
process is carried out automatically after closing
of the breaker on breakers with motor
charging mechanisms, but must be carried out
manually on breakers without charging motors
(or when the charging motor has broken down).
Opening of the breaker is also possible during
the (re-)charging process, but sub-sequent closing
of the breaker is however blocked until the
is
charging process has been completed.

3.3.5 Quenching principle of the vacuum interrupter

Due to the extremely low static interrupter chamber
pressure of 10
contact gap is required to achieve a high dielectric
strength. The arc is extinguished on one of the
first natural current zeros.
Due to the small contact gap and the high
conductivity of the metal vapour plasma, the arc
drop voltage, and additionally, due to the short
arcing time, the associated arc energy, are
extremely low, which has advantageous effects
on the life of the contacts and thus on that
of the vacuum interrupters.
-2 -6
to 10 pa, only a relatively small