CB Watch 3 User Manual v6.3 - May 2019 Page 23 of 100
Figure 29 – Operating time discordances
Note that even though the discrepancy value is shown under pole A, it does not indicate
that the maximum of the three discordance values is associated with pole A.
Separation speed & touching speed
A CB must operate at a specific speed in order to build up adequate pressure to allow for
a cooling stream of air, oil or gas (depending on the type of breaker) to extinguish the arc
that is generated after the contact separation and until the next zero crossing.
To enable speed calculations, the system requires two key distances to be entered
during setup, measured in mm from the fully open position which is 0mm. In this
example:
O Start of open position = location of 52b sensor 15mm here
C Start of close position = location of 52a sensor 120mm here
HMI: Settings/Opening and Settings/Closing
Figure 30 – Entry of key distances
The distance (C-O), in this example: 120-15=105mm, is assimilated to the travel distance
and the contact “separation speed” is calculated by dividing this distance by the
“opening travel time” (t2-t1) which has been recorded.
A similar calculation is done for the closing contact “touching speed” by using this travel
distance and the “closing travel time” (t2-t1)
HMI: Measurements/Last opening and closing results
To Next Page
Loading...
Need help?
General
