Motor HP Calculation Formula

Motor HP Formula (3-Phase):

\[ HP = \frac{V \times I \times \sqrt{3} \times PF \times Eff}{746} \]

Voltage (V):

volts

Current (I):

amps

Power Factor (PF):

(0-1)

Efficiency (Eff):

Horsepower (HP):

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1. What is the Motor HP Calculation Formula?

The Motor HP Calculation Formula estimates horsepower from electrical inputs for three-phase motors. It calculates mechanical power output based on voltage, current, power factor, and motor efficiency.

2. How Does the Calculator Work?

The calculator uses the 3-phase motor HP formula:

\[ HP = \frac{V \times I \times \sqrt{3} \times PF \times Eff}{746} \]

Where:

\( V \) — Voltage (volts)
\( I \) — Current (amps)
\( \sqrt{3} \) — Square root of 3 (1.732)
\( PF \) — Power factor (0-1)
\( Eff \) — Motor efficiency (%)
\( 746 \) — Watts per horsepower conversion factor

Explanation: The formula converts electrical power input to mechanical power output, accounting for three-phase power characteristics and motor efficiency losses.

3. Importance of HP Calculation

Details: Accurate horsepower calculation is crucial for motor selection, sizing electrical systems, determining load capacity, and ensuring proper motor operation without overload.

4. Using the Calculator

Tips: Enter voltage in volts, current in amps, power factor as decimal (0-1), and efficiency as percentage. All values must be positive and within valid ranges.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between 3-phase and single-phase HP calculation?
A: 3-phase uses √3 (1.732) factor while single-phase uses 1.0. Three-phase motors are more efficient and commonly used in industrial applications.

Q2: What is a typical power factor for motors?
A: Power factor typically ranges from 0.8 to 0.95 for most industrial motors, with higher values indicating better electrical efficiency.

Q3: How does motor efficiency affect HP calculation?
A: Efficiency represents the percentage of electrical input power converted to mechanical output power. Higher efficiency means less energy loss as heat.

Q4: Why is 746 used in the formula?
A: 746 watts equals 1 horsepower, providing the conversion from electrical power (watts) to mechanical power (horsepower).

Q5: When should this calculation be used?
A: Use for motor sizing, electrical system design, load analysis, and verifying motor performance specifications.