1VAL050503-MB Rev B Replaces (1VAL057485-MB Rev. C) Oct 2013
12
MECHANISM AND OPERATION
The EL operating mechanism of the Advac circuit breakers (in all versions) is fitted with
a mechanical anti-pumping device which prevents re-closing due to either electrical or
mechanical commands.
Should both the closing command and any one of the opening commands (local or re-
mote) be active at the same time, there would be a continuous succession of opening
and closing operations.
The anti-pumping device avoids this situation, ensuring that each closing operation is
only followed by a single opening operation and that there is no closing operation after
this. To obtain a further closing operation, the closing command must be released and
then re-launched.
Furthermore, the anti-pumping device only allows circuit-breaker closure if the following
conditions are present at the same time:
1. Closing spring fully charged
2. Opening mechanical pushbutton and/or opening release coils (-MO1/-MO2) are not
active.
3.
The circuit breaker is in the Open position.
Below is a side internal view of the EL mechanism and the associated anti-pumping component. When the
opening pushbutton or coils are activated the
opening shaft lever
pushes down on point
C
of the anti-pump
device. This causes the device to side down slot
D
in direction of arrow
B
. Then the trigger portion
A
moves
out from between the
closing push-button
and the
closing shaft lever
. So if the closing button or signal is
held active and the opening button or signal is then activated. The trigger
A
will pull out from between
clos-
ing shaft lever
and the
closing push button
. Once the open signal is released the trigger
A
will come to
rest under the
closing push-button
and will not return between the
closing shaft lever
and
closing push-
button
until the button or closing command is released.
The
closing push button
is operated by the closing coil (MC) directly by the
shaft closing device
. This al-
lows the
anti-pumping
device to prohibit closing by manual or electrical means.