Cb Failure Settings - DEMA CPM 310 G User Manual

A. CB Failure Settings window is accessed by clicking the CB Failure Settings button in the Automatic Control
Settings window.
B. Save to Buffer button sends the parameter changes to the DigiConnect buffer. When changes are to be
applied to CPM 310 G unit, Save to Device button must be utilized, which is located under the Buffer tab.
1. CB Failure Settings window comprises the control for having the CB protection function into or out of
service, as well as parameter setting fields.

CB Failure Supervision
This parameter can be set as Active or Passive to have the function into or out of service.

I<: CB Failure Threshold Current
I< is the upper limit of the circuit breaker pole current to decide that one or more poles of the circuit
breaker has failed to operate normally as the delay time expires. The function watches the 52a
(normally open auxiliary contact of the circuit breaker) input; once the 52a signal is lost, CB failure
delay time is counted until the pole current goes below the limit. If the current does not fall down
below the threshold value,
o
The function generates an alarm on the Alarm Menu and triggers the Alarm LED to inform the
user, and tells that a Circuit Breaker Failure condition is detected, or,
o
If applicable, triggers a dedicated output to start the configured alarming actions.
I< can be set as low as the current measurement lower limit, which is 0.02 I
be set to this value under normal conditions.

CB Failure Delay
CB failure delay time decides how long to wait before the measured current above the threshold value
is evaluated as a fault. Circuit breaker mechanical operation and arc extinguishing time values differ
for various brands and models, however, these values are below a certain value not exceeding 0.1s for
modern circuit breakers. Setting this value in the range of (0.05 – 0.1) s would be appropriate for most
of the applications. On the other hand, the set value may have to be determined beyond these values
for atypical cases.
It must be noted that, some requirements must be fulfilled for correct operation of this function;

A programmable input must be dedicated to this function with CB Failure Protection appointment, and
The dedicated input must be cabled to a normally open auxiliary contact of the circuit breaker. □
Settings » Automatic Control Settings » CB Failure Settings
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