Electric Motor Watts Formula:
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The electric motor watts calculation determines the input power required for an electric motor based on its horsepower rating and efficiency. This helps in proper electrical system design and energy consumption estimation.
The calculator uses the formula:
Where:
Explanation: The formula converts mechanical horsepower to electrical input power, accounting for the motor's efficiency losses.
Details: Accurate input power calculation is essential for proper circuit sizing, energy cost estimation, and ensuring electrical systems can handle motor starting and running currents.
Tips: Enter horsepower (must be greater than 0) and efficiency percentage (must be between 0 and 100). The calculator will compute the required input power in watts.
Q1: Why is 746 used in the formula?
A: 746 is the conversion factor from mechanical horsepower to electrical watts (1 HP = 746 watts).
Q2: What is typical motor efficiency?
A: Motor efficiency typically ranges from 70% to 95%, with higher efficiency in larger, more modern motors.
Q3: Does this account for starting current?
A: No, this calculates running watts only. Starting current can be 3-8 times higher than running current.
Q4: Can I use this for three-phase motors?
A: Yes, the formula works for both single-phase and three-phase motors when calculating input power.
Q5: How does voltage affect the calculation?
A: This calculation gives total power in watts. To find current (amps), divide watts by voltage (for DC) or by (voltage × power factor × √3 for three-phase AC).