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Three-Phase Motor Power Formula:
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Motor electrical power input refers to the actual power consumed by an electric motor from the electrical supply. For three-phase motors, this is calculated using the three-phase power formula that accounts for voltage, current, and power factor.
The calculator uses the three-phase power formula:
Where:
Explanation: The formula calculates the real power consumed by a three-phase motor, taking into account the phase relationship between voltage and current through the power factor.
Details: Accurate power calculation is essential for energy consumption analysis, electrical system design, motor selection, energy efficiency assessments, and cost calculations for industrial applications.
Tips: Enter line voltage in volts, line current in amperes, and power factor (typically 0.8-0.95 for motors). All values must be valid (voltage > 0, current > 0, power factor between 0-1).
Q1: What is power factor and why is it important?
A: Power factor represents the efficiency of power usage. A lower power factor means more apparent power is required to deliver the same real power, resulting in higher energy costs.
Q2: Can this formula be used for single-phase motors?
A: No, for single-phase motors use P = V × I × PF. The √3 factor is specific to balanced three-phase systems.
Q3: What is the typical power factor for electric motors?
A: Typically 0.8-0.95 for efficient motors under full load. Power factor decreases significantly under light loads.
Q4: How does this relate to mechanical power output?
A: Mechanical power output = Electrical power input × Motor efficiency. Efficiency typically ranges from 80-95% for standard motors.
Q5: Why use three-phase motors instead of single-phase?
A: Three-phase motors are more efficient, have higher power density, smoother operation, and are preferred for industrial applications above 1 HP.