BECKWITH ELECTRIC M-3425A, Instruction Book

Page: 249 / 482

4–118
M‑3425A Instruction Book
Breaker Monitoring
The Breaker Monitoring feature calculates an
estimate of the per-phase wear on the breaker
contacts by measuring and integrating the current
(
IT
) or current squared (
I
2
T
) passing through the
breaker contacts during the interruption period. The
per-phase values are added to an accumulated
total for each phase, and then compared to a user-
programmed threshold value. When the threshold
is exceeded in any phase, the relay can operate a
Expanded
Inputs IN7–IN14 (if equipped) must be set using
IPScom.
Expanded
Outputs OUT9–OUT23 (if equipped) must be set
using IPScom.
Figure 4-89 Breaker Monitor (BM) Setpoint Ranges
BM PICKUP
kA-cycles
BM INPUT INITIATE
i6 i5 i4 i3 i2 i1
BM OUTPUT INITIATE
08 07 06 05 04 03 02 01
BM DELAY
Cycles
BM TIMING METHOD
it i2t
programmable output contact. The accumulated
value for each phase can be displayed as an actual
value. The accumulation starts after a set time delay
from the trip initiate command to account for the time
it takes for the breaker to start opening its contacts.
The accumulation continues until the current drops
below 10% of the nominal current setting or 10
cycles, whichever occurs first.

NOTE
: Preset Accumulator Setpoints are only
available through IPScom
®
.