Formulas for Overcurrent / Ground Fault
- IDMT Multiply of Overcurrent settings formula:
T = t / ((IA/IT)-1)2
T：Overcurrent delay (seconds)
t：Timing multiplier ratio
IA：Current max. load current（L1/L2/L3）
IT：Overcurrent setting value
Example：
t = 36
IA = 550A
IT =500A
Conclusion: T = 3600 s
- Delay Multiplier for Ground Fault formula:
ground current delay action calculation (0.1s)=delay multiplier*0.14/(((ground current/ground current threshold)0.02)-1)