Answer / sudhakar g

HI,

First you have to check the settings of ACB breaker, If the
settings fault also it will be tripping. The following
settings you have to check in ACB are
1) Thermal Protection against " Overload faults ": Ir = 0.9
X 800A= 720A-Time delay = 2 sec
2) Magnetic Protection for " Short Circuit Faults " : Isd =
3 x 800A = 2400A- Time delay = 2 milli sec
3) Earth Fault Protection against direct fault between any
phase and the protection line : Ig = 200A (D)-Time delay = 2
milli sec
4) Instantaneous Protection against " Short Circuit Faults "
li = 3 x 3200 = 9600A for Big faults


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