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Motor starting current calculator

Inrush current for DOL, star-delta, soft starter and VFD starting.

A
× FLC
On the datasheet; typically 6–8
× FLC

Calculating…

How it's calculated

DOL: I = FLC × (IL/IN) Star-delta: I ≈ DOL current ÷ 3 Soft starter: I = FLC × current limit VFD: I ≈ 1–1.5 × FLC

Starting current matters for supply capacity, voltage dip on other equipment, generator sizing and protection settings. Star-delta cuts starting current and torque to about a third, so it suits fans and pumps but not high-inertia or heavily loaded starts.