3 Phase Motor Input Power Calculation

3 Phase Motor Input Power Formula:

\[ P_{input} = \sqrt{3} \times V \times I \]

Input Power (P_input):

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1. What is 3 Phase Motor Input Power?

Three-phase motor input power refers to the electrical power consumed by a three-phase motor from the power supply. It represents the total power input to the motor before accounting for losses and efficiency.

2. How Does the Calculator Work?

The calculator uses the 3-phase power formula:

\[ P_{input} = \sqrt{3} \times V \times I \]

Where:

\( P_{input} \) — Input power in watts (W)
\( V \) — Line-to-line voltage in volts (V)
\( I \) — Line current in amperes (A)
\( \sqrt{3} \) — Constant for 3-phase systems (approximately 1.732)

Explanation: This formula calculates the total power input to a balanced three-phase system, accounting for the phase relationships in three-phase power systems.

3. Importance of Input Power Calculation

Details: Calculating input power is essential for determining motor efficiency, sizing electrical components, calculating energy consumption, and ensuring proper system design and operation.

4. Using the Calculator

Tips: Enter line-to-line voltage in volts and line current in amperes. Both values must be positive numbers greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between input power and output power?
A: Input power is the electrical power supplied to the motor, while output power is the mechanical power delivered by the motor shaft. Output power is always less due to losses.

Q2: Does this formula account for power factor?
A: No, this basic formula assumes unity power factor. For more accurate calculations with non-unity power factor, use: \( P = \sqrt{3} \times V \times I \times PF \)

Q3: What are typical voltage and current values for 3-phase motors?
A: Common voltages include 208V, 230V, 460V, and 575V. Current varies significantly based on motor size and load, from a few amps to hundreds of amps.

Q4: Can this calculator be used for single-phase motors?
A: No, this calculator is specifically for three-phase systems. Single-phase power calculation uses different formulas.

Q5: How does motor efficiency affect power calculations?
A: Motor efficiency represents the ratio of output power to input power. To find output power, multiply input power by efficiency: \( P_{output} = P_{input} \times \eta \)