Electrical / 10
Motor Current Calculator
Estimate single-phase or three-phase motor current in A from shaft output power, supply voltage, power factor, and efficiency.
How it works
Ithree = P / (√3 × V × pf × eff); Isingle = P / (V × pf × eff)
A three-phase 5,500 W motor at 400 V, pf = 0.85, and efficiency = 0.9 draws approximately 10.38 A.
FAQ
Is power the electrical input power?
No. Enter rated mechanical shaft output in W. Efficiency converts output power to electrical input power.
Should I enter 90 for efficiency?
Enter 0.9 for 90%. Power factor and efficiency must be above zero and at most one.
Does this predict starting current?
No. It estimates steady running current for a balanced three-phase load or a single-phase load; starting current requires motor-specific data.