MA-037 - CB Watch 3 Operating Manual
v7.0 - May 2020
Page 42 of 118
Required data (without travel sensor present)
As seen in Section 5.2.5, the following distances (in mm) are required by the system to
calculate the contact separation speed:
O
End of open position ~ location of 52b sensor (ON when CB is OPEN)
C
End of close position ~ location of 52a sensor (ON when CB is CLOSED)
Look at the FAT timing test charts (or more recent tests) 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 clo
sing 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 (found in CB manual)
