1. What is the 100 HP Motor Current Calculation?

This calculator determines the amperage required for a 100 horsepower (HP) three-phase electric motor based on voltage, power factor, and motor efficiency. It's essential for proper circuit sizing and protection.

2. How Does the Calculator Work?

The calculator uses the following formula:

Where:

• 100 — Motor horsepower (HP)
• 746 — Conversion factor from HP to Watts
• √3 — Constant for three-phase systems (≈1.732)
• Voltage — Line-to-line voltage (V)
• Power Factor — Ratio of real power to apparent power (0-1)
• Efficiency — Motor efficiency (0-1)

Explanation: The formula converts horsepower to watts, then calculates the current draw considering the three-phase power characteristics and motor performance factors.

3. Importance of Current Calculation

Details: Accurate current calculation is crucial for selecting proper wire sizes, circuit breakers, and overload protection devices to ensure safe and efficient motor operation.

4. Using the Calculator

Tips:

• Enter the line-to-line voltage (typically 208V, 230V, 460V, or 575V for industrial motors)
• Typical power factor ranges from 0.8 to 0.95 for motors
• Motor efficiency typically ranges from 0.85 to 0.95
• All values must be positive numbers

5. Frequently Asked Questions (FAQ)

Q1: Why is 746 used in the formula?
A: 746 watts equals 1 horsepower, so we multiply by 746 to convert HP to watts.

Q2: What if my motor is single-phase?
A: For single-phase motors, remove the √3 factor from the denominator.

Q3: What are typical power factors for motors?
A: Induction motors typically have 0.85-0.9 PF at full load, dropping at lighter loads.

Q4: How does voltage affect current?
A: Current is inversely proportional to voltage - higher voltage means lower current for the same power.

Q5: Should I add a safety factor?
A: For real-world applications, add 25% to the calculated current for safety margins in sizing conductors and protection.