ABB AMVAC - OPENING AND CLOSING PROCEDURE

15
1VAL050601-MB Rev C
CIRCUIT BREAKER CONTROL:
All the conditions for control of the magnetic actuator mechanism are defined in a permanently programmed logic
module. These conditions are:
 Auxiliary voltage must be applied to the AC/DC converter.
 The storage capacitors must have sufficient charge for the next switching operation.
 The moving contacts in the circuit breaker poles must be in a defined CLOSE or OPEN limit position.
 The closing coil can only be activated with the circuit breaker in the OPEN position and there is sufficient energy.
 The opening coil can only be activated with the circuit breaker in the CLOSE position and there is sufficient energy.
 Closing is blocked when an opening command is simultaneously active.
 Activation of the closing coil can be disabled by an external blocking signal.
 The antipumping system ensures that, when a closing command is applied and followed by an opening command,
only one CLOSE-OPEN switching operation is performed. For the next closing operation, the active closing
command has to be cleared and must be issued again.
 Deactivation of the opening or closing coil takes place when the relevant limit position has been reached.
 All close signals must be by momentary contacts with a close time of 6-300ms.
OPENING AND CLOSING PROCEDURE: (Figures 2a to 2c, Page 16)
The opening and closing processes are initiated either by remote control via momentary closing contacts or locally by
manual operation of push-buttons (3) or (4).
In the closing process, the armature motion acts directly via the lever shaft (18) on the moving contact (24.1) until the
vacuum interrupter contacts meet.
In the full motion sequence, the spring arrangement (20) 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.
AUTORECLOSING SEQUENCE:
The operating mechanism is fundamentally prepared for autoreclosing, and with the short recharging time of the storage
capacitor it is also suitable for multi-shot autoreclosing.
VACUUM INTERRUPTER QUENCHING PRINCIPLE:
Due to the extremely low static interrupter chamber pressure of 10
-4
to 10
-8
mbar, only a relatively small contact gap is
required to achieve a high dielectric strength. The vacuum arc is extinguished on one of the first natural current zeros.
Due to the small contact gap, high conductivity of the metal vapor plasma, and short arcing time, the associated arc
energy is extremely low, which has advantageous effects on the life of the contacts and thus on that of the vacuum
interrupters.
Switch Position: Storage Capacitor Energy For:
OPEN CLOSE and OPEN
CLOSE OPEN
STRUCTURE AND FUNCTION
Provided by Northeast Power Systems, Inc. (NEPSI)