Koja je formula za snagu trofaznog motora?

The active (real) power consumed by a three-phase motor is P = √3 × V_L × I_L × cos φ × η, where V_L is line voltage, I_L is line current, cos φ is power factor, and η is motor efficiency. Without η, the formula gives shaft input power.

Koja je razlika između kW, kVA i kVAR?

kW is active (real) power that does useful work. kVA is apparent power — the total power drawn from the supply. kVAR is reactive power used to maintain magnetic fields. They form the power triangle: S² = P² + Q², where S is in kVA, P in kW, and Q in kVAR.

Koja je tipična faktor snage za elektromotor?

Tipičan faktor snage za asinkrone motore pri punoj opterećenju je 0,80–0,90. Pri djelomičnom opterećenju, faktor snage se značajno smanjuje — motor pri 25% opterećenja može imati faktor snage čak 0,40–0,55. Sinkroni motori mogu raditi sa jediničnim ili čak vodećim faktorom snage.

Šta je efikasnost motora i kako utiče na proračun snage?

Efikasnost motora η je odnos mehaničke izlazne snage prema električnoj ulaznoj snazi. Tipične vrijednosti: 85–96% za standardne motore, u zavisnosti od veličine. Motori sa IE3 premium efikasnošću obično premašuju 92%. Uvijek uključite η pri proračunu električne unosa iz nominirane mehaničke snage.

Kako da pronađem struju motora iz podataka na tablici motora?

Rearrange the formula: I = P / (√3 × V × cos φ × η). For example, a 15 kW motor at 400 V, PF 0.85, efficiency 0.91 draws I = 15000 / (√3 × 400 × 0.85 × 0.91) ≈ 28.0 A.

Besplatan Inženjerski Alat

Kalkulator snage trofaznog motora

Calculate active power P = √3 × V × I × cos φ × η for three-phase motors. Bidirectional — solve for any variable. Also shows apparent & reactive power.

IEC 60034 Bidirectional Power Triangle

Solve For

Line Voltage (V)

Line Current (A)

Power Factor cos φ (0–1)

Efficiency η (0–1)

Active Power (kW)

Quick presets

Results

Active Power P

—

Prividna snaga S

—

Reactive Power Q

—

Line Current I

—

Faktor snage / Efikasnost

—

Formula snage trofaznog motora

The active (real) power consumed or delivered by a three-phase AC circuit is:

P — active power (W or kW)
V_L — fazna napetost (V)
I_L — fazna struja (A)
cos φ — faktor snage (0–1)
η — efikasnost motora (0–1)

Power Triangle

Where S je prividna snaga (kVA), P is active power (kW), and Q is reactive power (kVAR).

Praktični primjer

Primjer — Motor od 15 kW na 400 V

Given: P = 15 kW, V = 400 V, cos φ = 0.85, η = 0.91

I = P / (√3 × V × cos φ × η) = 15000 / (1.732 × 400 × 0.85 × 0.91) = 28.0 A

S = √3 × V × I = 1.732 × 400 × 28.0 = 19.40 kVA

Q = √(S² − P²) = √(19.40² − 15²) = 12.30 kVAR

💡 Tip: Pri izračunavanju električne ulazne snage iz nominalnog mehaničkog izlaza motora, uvijek podijelite sa efikasnosti η. Nazivna kW na natpisnoj ploči je obično mehanički izlaz na vratilu.

A reliable **three phase motor power calculator** is an essential tool for electrical engineers and technicians who need to quickly determine active, apparent, and reactive power values without performing manual computations. By inputting known parameters such as line voltage, line current, power factor, and efficiency, this three phase motor power calculator applies the standard formula P = √3 × V × I × cos φ × η to deliver accurate results in seconds. Its bidirectional functionality allows you to solve for any unknown variable, making it invaluable for motor sizing, load analysis, and energy auditing tasks.