HAT700 SERIES ATS CONTROLLER USER MANUAL
HAT700 Series ATS Controller 2018-12-13 Version 1.5 Page 33 of 51
9.4 DEFINITE TIME DELAY AND INVERSE DEFINITE MINIMUM TIME SETTING
Definite Time
：
overcurrent delay is definite time delay. Different overcurrent value has corresponding
delay.
Inverse Definite Minimum Time(IDMT)
：
overcurrent delay decrease with the increase of overcurrent.
Different overcurrent value has corresponding delay.
IDMT formula:
T = t / ((IA/IT)-1)
2
T
：
Overcurrent delay (second)
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 = 3600s(1hour)
