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Induction Motor - Starting Current Estimate

Locked-rotor (inrush) current for a squirrel-cage induction motor - the basis for switchgear sizing and generator voltage-dip calculation.

MotorStartingDOL
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Formula, assumptions, and limits

In=P3ULcosφη,Is=kInI_n = \frac{P}{\sqrt{3} \cdot U_L \cdot \cos\varphi \cdot \eta}, \quad I_s = k \cdot I_n
SymbolMeaningUnit
PPMotor rated powerkW
ULU_LLine-to-line voltageV
kkLocked-rotor multiplier

Source: IEC 60034-12

In short

Locked-rotor (inrush) current for a squirrel-cage induction motor - the basis for switchgear sizing and generator voltage-dip calculation.

Learn the theory Marine Electrical Generation and Distribution