ABB VD4 Series Instruction Manual - page 22
22 VD4 Vacuum-circuit-breaker | Instruction manual 534/01
-MC and the optional blocking magnet -RL1 with the
circuit-breaker in the closed position. There is one further
NOC for other purposes.
- On failure or absence of the control voltage, blocking mag-
net -RL1 mechanically locks the ON half shaft and simulta-
neously acts on the corre sponding auxiliary switch -BL1 to
interrupt the circuit of shunt release ON -MC.
- Blocking magnet -RL1 is accessible when front plate 9.2 is
removed.
- Auxiliary switch -BB2 interrupts the circuit of shunt release
OFF -MO1 with the circuit-breaker in the open position.
One further NOC and three NCCs are available for annunci-
ation, control and interlock purposes.
- Auxiliary switch -BB3 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 auxiliary switch is
normally configured as shown in figure 2/15.
- The single pole auxiliary switch -BB4 (fleeting contact
time ≥ 30 ms) serves to provide a fault signal („breaker
released“).
- With remote control, the auxiliary switch is necessarily
operated by:
- Shunt release OFF -MO1 or
- Shunt release OFF -MO2 or
- Undervoltage release -MU or
- Indirect overcurrent release -MO3.
Note:
1. Shunt releases OFF -MO1 and ON -MC are exclusively
provided for opening and closing in normal operation. For
safety breaking operations, the second shunt release OFF
-MO2 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 undervoltage release -MU and/or indirect overcurrent
release -MO3 are pure safety and protection releases and
must not be used for switching in normal operation.
4.3.2 Mounting of the VD4 on trucks from other
manufacturers
VD4 circuit-breakers which are not installed on ABB withdra-
wable parts must be fitted with one or two additional auxiliary
switches which are dependent on the mechanical lock and
release device. These must interrupt the circuit of shunt
release ON -MC.
Similary to auxiliary switches -BT2 and -BT1 in Calor Emag
withdrawable parts, no electrial pulse may arrive during and
before mechanical blocking of the spindle mechanism, and
may only be applied again after the end of mechanical blocking.
This ensures that the shunt release ON cannot be loaded with
an electrical ON pulse when the withdrawable part is in an
intermediate position, which could burn out the coil.
4.4
Function
4.4.1 Charging of the spring energy storage mechanism
(Figures 4/6, 4/7 and 7/1)
To provide the necessary motive energy, the spring energy
storage mechanism, either charged auto matically by a char-
ging motor or manually in a vertical pumping action with
charging lever 19, depending on the equipment fitted to the
circuit-breaker. The current charging condition is shown at
charging condition indicator 18.
As a precondition for an auto-reclosing sequence, the opera-
ting 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.
4.4.2 Closing procedure
(Figures 4/4, 4/6 and 4/7)
The closing process is started by the mechanical ON push-
button 11, or by activation of shunt re lease ON -MC. The
release mechanism 31 then permits drive shaft 30 to be
rotated by the (previously) charged spiral spring. The moving
contact 20.3 in vacuum interrupter 20 is moved until the
contacts touch by cam disk 29 and further kinematic links.
In the further sequence of motion, spring arrangement 25 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 27 are simulta-
neously tensioned
4.4.3 Opening procedure
(Figures 4/4, 4/6 and 4/7)
The opening procedure is initiated by mechanical OFF push-
button 12 or by activation of one of releases -MO1, -MU,
-MO3 or MO2. Observe the notes in section 4.3.1 on control
of the releases. Release mechanism 31 then permits drive
shaft 30 to be turned further by the spring energy storage
mechanism, which is still sufficiently charged. Opening spring
27, which is thus released, moves contact 20.3 into the open
position at a defined speed.
4.4.4 Auto-reclosing sequence
An OFF-ON or OFF-ON-OFF auto-reclosing se quen ce is acti-
vated 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 mo tors (or when the charging motor has
broken down). Opening of the breaker is also possible during
the (re-)charging process, but subsequent closing of the brea-
ker is however blocked until the charging process has been
completed.