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TDR9000
™
Circuit Breaker Test System User’s Guide
72A-1898 Rev. A 11/01 A-41
Monday
, November 26, 2001 1:09 pm
The selection made calculates the timing of the Main Contact (t
2
) and
resistor switch (t
1
), after the measurement by the designated channel
reaches 50% of the full scale current selected for that channel
(Figure A.42) if the T0 option is selected in ”Resistor Switch
Timing – Close” on page A-77. The measurements in Figure A.42 were
calculated using an external current probe with a selected range of 20 A.
Figure A.42 Close Timing from Current Measurement
If external shunt is used, let us say 5 V = 100 A, then the timing starts
when the shunt output reaches 2.5 V which corresponds to 50 A.
0 10 20 30 40 50 60
t
2
t
1
50% FS = 0.5 x 20 = 10 A
A
0
20
18 A