Electric Motor Power Calculator

Electric Motor Power Formula:

\[ HP = \frac{V \times I \times \eta \times PF}{746} \]

Voltage (V):

volts

Current (I):

amps

Efficiency (η):

Power Factor (PF):

Horsepower (HP):

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1. What is an Electric Motor Power Calculator?

Definition: This calculator estimates the mechanical power output of an electric motor in horsepower based on electrical input parameters.

Purpose: It helps engineers, technicians, and electricians determine motor performance and size motors appropriately for applications.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ HP = \frac{V \times I \times \eta \times PF}{746} \]

Where:

\( HP \) — Horsepower output
\( V \) — Voltage (volts)
\( I \) — Current (amps)
\( \eta \) — Motor efficiency (0-1)
\( PF \) — Power factor (0-1)
746 — Conversion factor (watts to HP)

Explanation: The formula calculates the real power (accounting for efficiency and power factor) and converts watts to horsepower.

3. Importance of Motor Power Calculation

Details: Accurate power calculation ensures proper motor selection, prevents overload conditions, and optimizes energy efficiency.

4. Using the Calculator

Tips: Enter the voltage, current, efficiency (default 0.9), and power factor (default 0.85). Efficiency and power factor must be between 0 and 1.

5. Frequently Asked Questions (FAQ)

Q1: What is motor efficiency?
A: The ratio of mechanical power output to electrical power input, typically 0.8-0.95 for good motors.

Q2: What is power factor?
A: The ratio of real power to apparent power, representing phase difference between voltage and current (typically 0.8-0.95).

Q3: Why divide by 746?
A: 1 horsepower equals 746 watts, so we convert electrical watts to mechanical horsepower.

Q4: Can I use this for three-phase motors?
A: For three-phase, multiply the result by √3 (approximately 1.732).

Q5: How do I find motor current?
A: Check motor nameplate or measure with a clamp meter under load.