1. What is Motor Horsepower?

Horsepower (HP) is a unit of measurement for power, commonly used to rate the output of engines and motors. It represents the rate at which work is done. In electrical motors, horsepower can be calculated from voltage, current, power factor, and efficiency.

2. How Does the Calculator Work?

The calculator uses the electrical horsepower formula:

Where:

• \( V \) — Voltage (volts)
• \( I \) — Current (amps)
• \( PF \) — Power factor (unitless, typically 0.8-0.95)
• \( \eta \) — Efficiency (decimal, typically 0.7-0.95)
• 746 — Conversion factor from watts to horsepower

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

3. Importance of Horsepower Calculation

Details: Knowing a motor's horsepower is essential for proper sizing, performance evaluation, and ensuring compatibility with mechanical loads.

4. Using the Calculator

Tips: Enter voltage in volts, current in amps, power factor (typically 0.8-0.95), and efficiency as a decimal (e.g., 90% = 0.90). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical power factor for motors?
A: Most AC induction motors have a power factor between 0.80-0.95 at full load, lower at partial loads.

Q2: How does efficiency affect horsepower?
A: Efficiency accounts for energy losses (heat, friction). Higher efficiency means more electrical power is converted to mechanical power.

Q3: Why 746 watts per horsepower?
A: This is the conversion factor established by James Watt (1 HP = 550 foot-pounds per second ≈ 746 watts).

Q4: Can I use this for DC motors?
A: Yes, for DC motors set PF = 1 (DC has no power factor) and use appropriate efficiency.

Q5: What's the difference between input and output HP?
A: Input HP is electrical power, output HP is mechanical power after efficiency losses. This calculator gives output HP.