3 Phase Motor kWh Calculator

3-Phase Energy Formula:

\[ E_{kWh} = \frac{V \times I \times PF \times \sqrt{3} \times t}{1000} \]

Voltage (V):

volts

Current (I):

amps

Power Factor (PF):

Time (t):

hours

Energy Consumption (E_kWh): kWh

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1. What is a 3 Phase Motor kWh Calculator?

Definition: This calculator estimates the energy consumption of a three-phase electric motor in kilowatt-hours (kWh).

Purpose: It helps engineers, electricians, and facility managers determine the electrical energy usage of three-phase motors for cost analysis and efficiency calculations.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ E_{kWh} = \frac{V \times I \times PF \times \sqrt{3} \times t}{1000} \]

Where:

\( E_{kWh} \) — Energy consumption (kilowatt-hours)
\( V \) — Voltage (volts)
\( I \) — Current (amps)
\( PF \) — Power factor (unitless, 0-1)
\( t \) — Time (hours)
\( \sqrt{3} \) — Constant for three-phase systems (~1.732)

Explanation: The formula calculates real power consumption by accounting for the three-phase power characteristics and converts it to kilowatt-hours.

3. Importance of 3-Phase Energy Calculation

Details: Accurate energy calculation helps in:

Predicting electricity costs
Assessing motor efficiency
Sizing electrical systems
Comparing different motor options

4. Using the Calculator

Tips:

Enter line-to-line voltage (typically 208V, 230V, 460V, or 575V)
Measure current under normal operating load
Power factor is typically 0.8-0.95 for motors (default 0.85)
Time should be in hours (use decimals for minutes, e.g., 0.5 for 30 minutes)

5. Frequently Asked Questions (FAQ)

Q1: Why is √3 used in the formula?
A: The √3 factor accounts for the phase difference in three-phase systems, converting line-to-line measurements to total power.

Q2: How do I find the power factor?
A: Check motor specifications, use a power meter, or estimate (0.85 is typical for motors under load).

Q3: Does this work for single-phase motors?
A: No, for single-phase use: \( E_{kWh} = \frac{V \times I \times PF \times t}{1000} \) (without √3).

Q4: Should I use line or phase voltage?
A: Use line-to-line voltage (what you'd measure between any two phases).

Q5: How accurate is this calculation?
A: It provides a good estimate but actual consumption may vary with motor efficiency, load variations, and voltage fluctuations.