1. What is the Electric Motor Power Formula?

The electric motor power formula calculates the real power consumption of a three-phase AC motor. It accounts for voltage, current, and power factor to determine the actual power being used.

2. How Does the Calculator Work?

The calculator uses the three-phase power formula:

Where:

• \( P \) — Power in watts (W)
• \( V \) — Line-to-line voltage in volts (V)
• \( I \) — Current in amperes (A)
• \( PF \) — Power factor (unitless, between 0 and 1)

Explanation: The square root of 3 (≈1.732) accounts for the phase difference in three-phase systems. The power factor represents the ratio of real power to apparent power.

3. Importance of Power Calculation

Details: Accurate power calculation is essential for sizing electrical components, determining energy consumption, calculating efficiency, and ensuring proper motor operation.

4. Using the Calculator

Tips: Enter line-to-line voltage in volts, current in amps, and power factor (typically 0.8-0.95 for motors). All values must be positive (voltage > 0, current > 0, 0 < PF ≤ 1).

5. Frequently Asked Questions (FAQ)

Q1: What is power factor?
A: Power factor is the ratio of real power (doing work) to apparent power (product of voltage and current). It ranges from 0 to 1, with higher values being more efficient.

Q2: How do I measure voltage and current?
A: Use a multimeter or clamp meter to measure line-to-line voltage and current. For three-phase systems, measure between any two phases for voltage.

Q3: What's a typical power factor for motors?
A: Induction motors typically have power factors between 0.8-0.9 at full load, lower at partial loads. Synchronous motors can achieve unity (1.0) power factor.

Q4: Does this work for single-phase motors?
A: No, for single-phase motors use \( P = V \times I \times PF \) (without the √3 factor).

Q5: How does this relate to horsepower?
A: To convert watts to horsepower, divide by 746 (1 HP = 746 W). Motor nameplate HP is output power, while this calculation gives input power.