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
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
(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(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
E L-L
Z
% ML
Source for Formulas: Cooper Bussman Short Circuit Calculations PDF