37
A INPUT POLARITY
(Aux A Input Assertion Level)
Entering the proper Aux A input assertion level allows the
OPTI
mizer
2
to properly start the mechanism time, arc
time, and duty wear logs. The
OPTI
mizer
2
reacts to a
change in voltage state when the breaker is proceeding
from the closed position to the open position. These are
defined to the
OPTI
mizer
2
as:
• No-voltage to voltage = “Positive”
• Voltage to no-voltage = “Negative”
Note:
When the
OPTI
mizer
2
is cold-started, the A Input
Polarity parameter is set to “Positive”.
A Input Polarity:
The A Input Polarity is selected from a
pull-down list.
To determine the assertion level, reference is made to the
following diagrams.
OPTImizer
2
Aux A
Input
+
R
T/2
T/1
52/a
TC
Closed Open
A Input Polarity
= Negative
Figure 12: Aux A Interface, using Trip Initiate (Red Light)
This is an elementary diagram of a typical trip circuit. The
elements T / 1 and T / 2 are trip-initiating contacts. These
could be from protective relays, manual trip switches,
SCADA contacts, etc. With the
OPTI
mizer
2
Aux A input
wired in parallel with the trip initiates, (red light), the
voltage levels sensed by the Aux A input during a trip
operation would be as follows:
• Breaker Closed - The trip initiates are open, the red
light is lit, as the 52 / a contact is closed and a low
current is passing through the trip coil. The Aux A
input would sense voltage.
• Trip Command - One of the trip initiate contacts
closes, shunting the red light and the Aux A input.
This causes high current to flow through the trip coil,
which begins to pull the latch. The Aux A input would
sense a transition from voltage to no-voltage.
• Breaker Travel - As the breaker begins to travel, the
52 / a contact opens, effectively causing an open
trip circuit. The Aux A input would still sense a no-
voltage condition (which will remain even after reset
of the trip initiate contacts).
• Fully Opened - The 52 / a contact remains open,
effectively causing an open trip circuit. The Aux
A input would continue to sense a no-voltage
condition.
In summation, the OPTI
mizer
2
, when applied in parallel
with the trip initiates, should be set as:
•
A Input Polarity = “Negative”
• INPUT MODE = “1” or “3”
