CB Watch 3 User Manual v6.3 - May 2019 Page 34 of 100
Required data (without travel sensor present)
As seen in Section 4.2.5, the following distances (in mm) are required by the system to
calculate the contact separation speed:
O Start of open position ~ location of 52b sensor (ON when CB is OPEN)
C Start of close position ~ location of 52a sensor (ON when CB is CLOSED)
Look at old timing test charts to ascertain how far they are located (travel distance when
52b contact changes state). Typically, O will be between 10-15mm (~10% of the total
travel stroke) and C will be at ~90% of total travel stroke. Example: if stroke 135mm, C:
~120mm.
The difference (C-O) will be equivalent to ~80% of the total travel stroke and will
determine the “distance travelled” during the opening or closing operation used to
calculate the contact separation and touching speed:
Contact separation speed = distance travelled / opening travel time
Contact touching speed = distance travelled / closing travel time
Required data (with travel sensor present)
When a travel sensor is present and used, the following distances (in mm) are required by
the system. The timing is measured when the travel sensor reaches these positions:
A: Open position Always “0mm” as we start measuring from that position
It is not required to enter that value
B: Open position limits Tolerance on the open position
Usually set to -5mm (min) and +5mm (max)
C: Start of open position Same as in previous section above
D: Separation of contact From open position to middle of arcing contact wipe range.
Found in the CB manual. Example: 25mm
E: Start of close position Same as in previous section above
F: Closed position limits Found in the CB manual. Example 195-202mm.
Mid-point is 198 -3mm/+4mm
The mid-point becomes the closed position and the
tolerances become the closed position limits
G: Closed position Full stroke of CB
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