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MA-037 - CB Watch 3 Operating Manual
v7.0 - May 2020
Page 65 of 118
Arcing time historical graph
A graph displaying the history of the arcing times recorded is available. With a point for each
opening operation, it provides an easy visual method of spotting variations and trends in the
recorded values over time.
The graphs can be found in the Operations Charts section:
HMI: Measurements/Operations charts/Opening
Figure 98
–
Arcing time historical chart
Arcing contact wear
Contact electrical wear
During the period from the separation of the contacts (time Ts) and until definitive
extinction of the current (time Ta), we cumulate the squared amps interrupted by the circuit
breaker to estimate the electrical deterioration induced by the operation. We do that
independently for each phase/pole.
Electrical contact wear per operation =
(Irms).(i(t))
2
dt
The function
above is set by default to: f(Irms)=1 for all Irms values.
The calculated value above represents the electrical deterioration for the operation under
consideration. It is then added to the cumulative figure to obtain the total electrical wear
per phase that the contact has endured so far.
Cumulative electrical contact wear =
Electrical contact wear per operation
The cumulative electrical contact wear is displayed in the HMI after each operation: