Starting-current multiplier on full-load amps for DOL, star-delta, autotransformer, and soft-starter modes.
Formula
$$ I_\text{start} = I_\text{LRC} \cdot k_\text{method}, \quad k_\text{Y-Δ} = \tfrac{1}{3}, ; k_\text{auto} = a^2 $$
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $FLC$ | Full-load current | A | nameplate |
| $I_\text{LRC}$ | Locked-rotor current = DOL × multiplier | A | nameplate |
| $a$ | Autotransformer tap ratio | - | 50/65/80 % |
Sources
- IEC 60947-4-1 - Contactors and motor starters.