ABB AMVAC Installation And Operation Manual page 14

S
TORAGE CAPACITORS
The energy for the operation of the circuit breaker is stored electrically in two storage capacitors. The breaker is de-
signed in such a way that when the capacitors are fully charged, there is enough energy for an O-C-O (Open-Close-
Open)* operating sequence without the recharging of the capacitors.
The energy stored by the capacitor is continuously monitored. This is achieved by the control unit constantly measuring
the capacitor voltage.
The "READY" lamp indicates whether the circuit breaker is functional or not, and indicates if the circuit breaker is ready
or not ready to operate. Note: Observe connecting the auxiliary voltage as described in the Operation,
Installation, and Maintenance section.
The energy available in relation to the relevant switch position after auxiliary power loss is the criteria which determines
whether a switching operation can be performed or an error message is issued:

Case 1: Circuit breaker in the OPEN position
The energy available is sufficient for a CLOSE and OPEN switching operation.

Case 2: Circuit breaker in the CLOSED position
 The energy available is sufficient for a OPEN-CLOSE-OPEN switching sequence.
 The energy available is sufficient for an OPEN switching operation up to 200 seconds after failure of the auxiliary
power supply.
* 0.3 seconds for each operation
Inside the breaker there are stored energy capacitors that must be discharged prior to removing the
front cover of the breaker. Wait 10 minutes after breaker removal from the cell prior to removing the
front cover of the breaker for the discharging of the storage capacitors to occur.
S S :
ENSOR YSTEM
(Figure 2d)
The systematic use of sensors permits control of the circuit breaker without auxiliary switches.
Two inductive proximity switches (15) and (16) are used to detect the mechanical limit positions. These two proximity
switches also provide self-monitoring of the system.
CIRCUIT BREAKER FUNCTION
M
AGNETIC ACTUATOR
The magnetic actuator is the heart of the circuit breaker operating mechanism. It combines the following integrated
functions:

Latching in the limit positions

Release

Switching
The actuator is a bistable permanent magnet system in which the armature motion is affected by activating the close or
open coil. In the limit positions the armature is held in place magnetically by the fields of the two permanent magnets.
Changing of the breaker's switched position is performed by exciting one of the two electromagnet coils (open or close)
until the latching force of the permanent magnets (13) are exceeded and the magnet armature (12) is shifted up or down
depending upon the operation.
14
STRUCTURE AND FUNCTION
:
(Figure 2c)
:
Figures 2b and 2c)
(
1VAL050601-MB Rev C
DANGER