ABB VM1 Installation And Service Instructions Manual page 11

M E D I U M V O LTA G E P R O D U C T S
6.1.2. Capacitor
The energy for operating the circuit breaker is
stored in one or two capacitors according to the
circuit breaker model (fig. 5).
The capacitors are designed so that the energy for
an O-C-O operating cycle is supplied without the
need for recharging.
The energy stored by the capacitor is constantly
monitored by means of measuring the voltage of
the capacitor.
The "READY" indication signals application of the
power supply voltage and the "ready" state of the
circuit breaker for the next operation.
The energy stored in the capacitors determines
the position of the READY/NOT READY contacts
and lighting up of the luminous "READY" signal
according to the following criteria.
• Case 1: circuit breaker in the open position.
- The energy available is sufficient for one closing
and opening operation.
• Case 2: circuit breaker in the closed position.
- The energy available is sufficient for one opening
operation.
Fig. 5
- The energy available is sufficient for one opening
operation within 60 s from interruption of the
auxiliary power supply.
If the energy stored is not sufficient, the luminous
"READY" signal is off, the "READY" contact is open
and the "NOT READY" contact is closed to indicate
that the circuit breaker is not ready for the
operation.
When there is no auxiliary voltage, the capacitor is
able to keep the circuit breaker operational for
about 2 minutes.
6.1.3. Position sensors
The use of two inductive proximity sensors (fig. 6)
allows the state of the circuit breaker (open -
closed - anomalous intermediate position) to be
determined without the use of auxiliary contacts,
allowing continual monitoring of the system.
The signal of the two sensors is sent to the
electronic control module.
Fig. 6
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