Transformer Inrush Current Calculator

Estimate transformer inrush current magnitude and duration for protection coordination.

Transformer kVA rating.
kVA
Primary winding voltage.
V
Transformer impedance percentage.
%
1 for single-phase, 3 for three-phase.

Results

Full Load Current-A
Peak Inrush Current-A
Inrush Multiplier-×FLA
Inrush Duration-cycles
References: IEEE C57.12.00; IEEE C37.91; ANSI C84.1