1. What is Horsepower to Amperage Conversion?

Definition: This calculator converts mechanical horsepower to electrical current (amperage) for motors.

Purpose: It helps electricians and engineers determine the current draw of electric motors based on their horsepower rating.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( I \) — Current in amperes (A)
• \( HP \) — Horsepower rating
• \( V \) — Voltage (V)
• \( \eta \) — Motor efficiency (0-1)
• \( PF \) — Power factor (0-1)

Explanation: The formula converts horsepower to watts (746W per HP), then calculates current considering voltage, efficiency, and power factor.

3. Importance of Amperage Calculation

Details: Proper current calculation ensures correct wire sizing, circuit breaker selection, and prevents electrical system overload.

4. Using the Calculator

Tips: Enter the motor horsepower, system voltage (default 120V), motor efficiency (default 0.9), and power factor (default 0.8). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why 746 in the formula?
A: 1 horsepower equals 746 watts, which is the conversion factor between mechanical and electrical power.

Q2: What's a typical motor efficiency?
A: Standard motors are typically 85-95% efficient (0.85-0.95), with higher efficiency for premium motors.

Q3: What affects power factor?
A: Power factor ranges from 0-1 and is affected by motor type, load, and design. Typical values are 0.8-0.95.

Q4: Does this work for three-phase motors?
A: This formula is for single-phase. Three-phase requires multiplying the denominator by √3 (1.732).

Q5: How do I account for startup current?
A: Motor starting current is typically 4-8 times running current. Consult motor specifications for exact values.