Transformer energising inrush current 6–12× rated - basis for relay pickup and breaker withstand.
Formula
$$ I_{inrush} = k \cdot I_n $$
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $I_n$ | Rated current | A | nameplate |
| $k$ | Inrush multiplier | - | design / maker data |
Sources
- IEEE C57.91.