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Prąd • Amps • Moc

Oblicz prąd

Prąd dla instalacji jednofazowych lub trójfazowych z mocy, napięcia i cos φ.

Wartości obliczeń

Uwaga: To obliczenie jest technicznie poprawnym uproszczeniem typowym dla kalkulatorów online. Przy doborze praktycznym trzeba również sprawdzić normy, sposób ułożenia, temperaturę, grupowanie, zabezpieczenia, typ kabla i dane producenta.

Zastosowany wzór

Single-phase: I = P / (U × cos φ)

Three-phase: I = P / (√3 × U × cos φ)

Practical guidance

Oblicz amperes for the correct electrical system

The general current calculator shows why equal active power produces different currents in single- and three-phase systems.

Input values explained

Prąd type
The current type determines whether the calculation uses factor 2 for outgoing and return conductors or √3 for balanced three-phase power.
Moc w watach
Use the electrical active power drawn by the load. A nameplate, data sheet or power meter is more reliable than an estimate.
Napięcie
Match the voltage to the selected electrical system. Single-phase calculations use line-to-neutral voltage, while three-phase calculations use voltage between two line conductors.
Moc factor cos φ
cos φ is the ratio of active to apparent power. It is close to 1 for resistive heating loads; use the data-sheet value for motors and transformers.

Example: 3,500 W at 230 V

A single-phase load takes 3,500 W at 230 V with a power factor of 0.90.

I = 3,500 W ÷ (230 V × 0.90) ≈ 16.91 A

The calculated operating current is 16.91 A. With a resistive load at cos φ 1 it would be about 15.22 A.

Prąd is not a fuse rating

This is steady operating current. A cable or protective device must not be selected merely by rounding it up.

Calculation limits

  • Efficiency, inrush, harmonics and short peaks are excluded.
  • The balanced formula is unsuitable for an unbalanced three-phase load.