3 Phase Motor Power Calculation

3 Phase Motor Power Formula:

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

Voltage (V):

Current (I):

Power Factor (PF):

(0 to 1)

Efficiency (Eff):

(0 to 1)

Motor Power (P):

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1. What is 3 Phase Motor Power Calculation?

The 3 Phase Motor Power Calculation determines the real power consumed by a three-phase electric motor, accounting for voltage, current, power factor, and efficiency. It's essential for proper motor sizing and electrical system design.

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)
\( V \) — Line-to-line voltage (volts)
\( I \) — Line current (amperes)
\( PF \) — Power factor (0 to 1)
\( Eff \) — Motor efficiency (0 to 1)

Explanation: The formula calculates the actual power consumed by the motor, accounting for both the reactive power component (power factor) and energy losses (efficiency).

3. Importance of Motor Power Calculation

Details: Accurate power calculation is crucial for proper motor selection, circuit protection sizing, energy consumption estimation, and electrical system design.

4. Using the Calculator

Tips: Enter line-to-line voltage in volts, line 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.

5. Frequently Asked Questions (FAQ)

Q1: What is power factor in motor calculations?
A: Power factor represents the ratio of real power to apparent power, accounting for phase difference between voltage and current caused by motor inductance.

Q2: Why is efficiency included in the calculation?
A: Efficiency accounts for energy losses in the motor (heat, friction), so the calculation reflects actual power drawn from the electrical system.

Q3: Is this formula valid for all 3-phase motors?
A: Yes, it applies to all balanced 3-phase AC motors (induction, synchronous, etc.) when operating under steady-state conditions.

Q4: How do I measure line-to-line voltage?
A: Use a multimeter between any two phase conductors (L1-L2, L2-L3, or L3-L1) in a 3-phase system.

Q5: What's the difference between real power and apparent power?
A: Real power (W) does actual work, while apparent power (VA) includes reactive power. The ratio is the power factor.