Power Calculation Formula for 3 Phase Motor

3-Phase Motor Power Formula:

\[ P = \sqrt{3} \times V \times I \times PF \times Eff \]

Voltage (V):

Current (I):

Power Factor (PF):

(0-1)

Efficiency (Eff):

(0-1)

Power Output (P):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the 3-Phase Motor Power Formula?

The 3-phase motor power formula calculates the real power output of a three-phase AC motor. It accounts for line-to-line voltage, current, power factor, and motor efficiency to determine the actual mechanical power delivered.

2. How Does the Calculator Work?

The calculator uses the 3-phase power formula:

\[ P = \sqrt{3} \times V \times I \times PF \times Eff \]

Where:

\( P \) — Real power (watts, W)
\( V \) — Line-to-line voltage (volts, V)
\( I \) — Current (amperes, A)
\( PF \) — Power factor (unitless, 0 to 1)
\( Eff \) — Motor efficiency (unitless, 0 to 1)

Explanation: The √3 factor accounts for the phase difference in three-phase systems. The power factor represents the ratio of real power to apparent power, and efficiency accounts for energy losses in the motor.

3. Importance of Power Calculation

Details: Accurate power calculation is essential for motor sizing, electrical system design, energy efficiency analysis, and proper circuit protection. It helps determine the actual mechanical power output rather than just the electrical input power.

4. Using the Calculator

Tips: Enter line-to-line voltage in volts, current in amps, power factor (typically 0.8-0.95 for motors), and efficiency (typically 0.85-0.95 for standard motors). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between real power and apparent power?
A: Real power (P, in watts) is the actual usable power, while apparent power (S, in VA) is the product of voltage and current. The ratio between them is the power factor.

Q2: Why is power factor important?
A: Lower power factors mean more current is required to deliver the same real power, increasing system losses and requiring larger conductors.

Q3: What are typical efficiency values for motors?
A: Standard motors range from 85-95% efficient. Premium efficiency motors can reach 95-97% at full load.

Q4: How does voltage affect motor power?
A: Power is directly proportional to voltage. A 10% voltage drop results in approximately 10% less power output.

Q5: Can this formula be used for single-phase motors?
A: No, single-phase motors use P = V × I × PF × Eff (without the √3 factor).