Motor Horsepower (HP) Calculation Formula

Motor Horsepower Formula:

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

Voltage (V):

volts

Current (I):

amps

Power Factor (PF):

(0-1)

Efficiency (η):

(0-1)

Horsepower (HP):

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1. What is the Motor Horsepower Formula?

The motor horsepower formula calculates the mechanical power output of an electric motor based on its electrical input characteristics. It accounts for voltage, current, power factor, and efficiency to determine the actual power delivered to the load.

2. How Does the Calculator Work?

The calculator uses the motor horsepower formula:

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

Where:

\( V \) — Voltage (volts)
\( I \) — Current (amps)
\( PF \) — Power factor (unitless, 0-1)
\( \eta \) — Efficiency (decimal, 0-1)
746 — Conversion factor from watts to horsepower

Explanation: The formula converts electrical power (adjusted for power factor and efficiency) to mechanical horsepower. One horsepower equals 746 watts.

3. Importance of HP Calculation

Details: Accurate horsepower calculation is essential for motor selection, sizing mechanical systems, determining load capacity, and ensuring proper electrical supply.

4. Using the Calculator

Tips: Enter voltage in volts, current in amps, power factor (typically 0.8-0.95), and efficiency (typically 0.8-0.95 for most motors). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between input and output horsepower?
A: Input HP is the electrical power consumed, while output HP is the mechanical power delivered. This calculator determines output HP after accounting for efficiency losses.

Q2: Why is power factor important?
A: Power factor accounts for the phase difference between voltage and current in AC systems. Lower PF means more current is required for the same real power.

Q3: What are typical efficiency values for motors?
A: Small motors (1-5 HP) typically have 80-85% efficiency, while larger motors (50+ HP) can reach 95% efficiency.

Q4: Can this be used for three-phase motors?
A: For three-phase motors, you need to multiply by √3 (1.732) and use line-to-line voltage.

Q5: How does motor speed affect horsepower?
A: Horsepower is directly related to torque and speed (HP = Torque × RPM / 5252). This calculator determines power output regardless of speed.