Thytronic NC020 - APPENDIX A3 - CAPACITOR Curves; Mathematical Formula

APPENDIX
79
NC020 - Manual - 05 - 2022
8.3 APPENDIX A3 - CAPACITOR curves
— Mathematical formula
The mathematical formula is:
Where:
• t = operate time (in seconds)
• t
I>inv
= setting time multiplier (in seconds)
• I
RMS
= input current
• I>
inv
= threshold setting
For inverse time characteristics, following data applies:
• Asymptotic reference value (minimum pickup value): 1.1 I>
inv
• Minimum operate time: 0.1 s
• Range where the equation is valid:
[1]
I / I>
inv
• If I> pickup ≥ 2.5 I
n
, the upper limit is 50 I
n
Note 1 When the input value is more than 20 times the set point , the operate time is limited to the value corresponding to 20 times the set point
t =
t>
inv
·
[1.1·(I
RMS
/I>
inv
)
17
-1]
+ 0.1
50000