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Quick Fault Current Calculator

I f.l. = Full Load Amperes
I S.C. = Short Circuit Current
KVA = The KVA of your transformer, or bank of transformers
% ML = Percent Motor Load
E L-L = Voltage Line to Line
Z = Impedance
100 / Z = Multiplier

Three Phase Calculations:
(KVA X 1000) / (E L-L X 1.732) = Three Phase Full Load Amps, I f.l.
100 / Z = Multiplier
If.l. X Multiplier = Transformer let thru Short Circuit Current, I S.C.
4 X FLA X % ML = Motor Load Contribution to Fault Current, I S.C. motor cont.
I S.C. + I S.C. motor cont. = Total Short Circuit Current, I S.C. Total

Single Phase Calculations:
(KVA X 1000) / E L-L = Single Phase Full Load Amps, I f.l.
100 / Z = Multiplier
If.l. X Multiplier = Transformer let thru Short Circuit Current, I S.C.
4 X FLA X % ML = Motor Load Contribution to Fault Current, I S.C. motor cont.
I S.C. + I S.C. motor cont. = Total Short Circuit Current, I S.C. Total

KVA
E L-L
Z
% ML

Source for Formulas: Cooper Bussman Short Circuit Calculations PDF

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