M ED I U M VO LTAG E P R O D U C T S
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7.3. Opening and closing procedure
(Refer to figure 10)
The opening and closing processes are initiated
either by remote control via closing contacts or
locally by manual operation of push-buttons
In the closing process, the armature motion acts
directly via the lever shaft (8) on the moving contact
until the vacuum interrupter contacts meet.
In the full motion sequence, the spring arrangement
(6) 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.
7.4. Autoreclosing sequence
The operating mechanism is SUITABLE for
autoreclosing, and with the short recharging time
of the storage capacitor it is also suitable for multi-
shot autoreclosing.
Thanks to the short duration of capacitor
recharging, the drive is suitable for multiple
reclosing operations with O-0.3s-CO-3min-CO
cycle.
7.5. Control module
The control module is available in the full option
version.
7.6. Functions of the control
module
All the conditions for controlling the opening and
closing commands given to the magnetic actuator are
managed by a microprocessor:
•
the power supply voltage must be applied to the
AC/DC converter.
•
the capacitor must be sufficiently charged for the
next operation:
Circuit breaker position
Operations
Open
Closing and Opening
Closed
Opening
•
the closing coil can only be activated when the
circuit breaker is open
•
the opening coil can only be activated when the
circuit breaker is closed
•
closing is disabled when an opening command is
active at the same time
• de-activation of the opening or closing coil takes
place when the relative limit position has been
reached.
•
WRONG POSITION (auto trip) function: if the final
CLOSED (or OPEN) position is not reached within 70
ms during a closing (or opening) operation, an
opening operation is immediately started to
guarantee reaching a defined safe position in any
case.
• The anti-pumping function ensures that only one
closing-opening cycle is carried out when a closing
command followed by an opening command is
active. The active closing command must be
cancelled and reset for the next closing operation.
•
Activation of the input for the closing command can
be locked by means of an external locking signal.
•
The input for the “lock on closing” command must
be energised to be able to close the circuit breaker
(without power it inhibits closing).
•
Undervoltage function: controls circuit breaker
opening if the voltage applied drops below the limit
of tolerance (established by the Standards).
The rated voltage value to be monitored is set in the
factory in conformity with the order specifications.
To prevent the function intervening when the
voltage drops below the specified level (e.g. in the
case of motor starting), it is possible to set a trip
time (see Fig. 8).
If no voltage is applied to the undervoltage function
input, it is impossible to close the circuit breaker.
The undervoltage function can be disabled.
In this case, it is possible to open and close the
circuit breaker without applying voltage to the input
of the function. It is also possible to select either the
circuit breaker lock in the open state or permission
to reclose the circuit breaker after an opening
operation for undervoltage.
•
Monitoring function of the actuator closing and
opening coil.
This function serves to monitor the continuity of the
closing and opening coils of the magnetic actuator
to detect any faults.
If a fault is detected, the luminous “READY” signal
on front of the circuit breaker turns off and the
“READY/NOT READY” signalling contacts are
activated.
•
Additional safety opening command function.
The second input of the control module for the
opening function is designed so that an opening
command is carried out directly even in the case of a
fault in the microprocessor.
Summary of Contents for VM1/A/P
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