Amp Calculator Voltage Horsepower

Electrical Current Formula:

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

Horsepower (HP):

Voltage (V):

Efficiency (η):

(0-1)

Power Factor (PF):

(0-1)

Current (I):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the Electrical Current Formula?

The electrical current formula calculates the current (in amperes) required for a motor based on its horsepower rating, voltage supply, efficiency, and power factor. This is essential for proper electrical system design and motor selection.

2. How Does the Calculator Work?

The calculator uses the electrical current formula:

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

Where:

\( I \) — Current in amperes (A)
\( HP \) — Horsepower rating of the motor
\( 746 \) — Conversion factor (watts per horsepower)
\( V \) — Voltage supply in volts (V)
\( \eta \) — Motor efficiency (0-1, typically 0.8-0.95)
\( PF \) — Power factor (0-1, typically 0.8-0.95)

Explanation: The formula converts horsepower to watts, then calculates the actual current draw considering motor efficiency and power factor.

3. Importance of Current Calculation

Details: Accurate current calculation is crucial for proper wire sizing, circuit breaker selection, transformer sizing, and ensuring electrical system safety and efficiency.

4. Using the Calculator

Tips: Enter horsepower, voltage, efficiency (as decimal), and power factor (as decimal). All values must be positive numbers with efficiency and power factor between 0.01 and 1.

5. Frequently Asked Questions (FAQ)

Q1: Why is 746 used in the formula?
A: 746 watts equals 1 horsepower, which is the standard conversion factor for mechanical to electrical power.

Q2: What are typical efficiency values for motors?
A: Standard efficiency motors range from 0.8-0.9, while high-efficiency motors can reach 0.95 or higher.

Q3: What is power factor and why is it important?
A: Power factor represents the ratio of real power to apparent power. Low power factor increases current draw and reduces system efficiency.

Q4: Can this formula be used for three-phase motors?
A: This formula is for single-phase AC motors. Three-phase calculations require additional factors.

Q5: How does voltage affect current calculation?
A: Higher voltage reduces current for the same power output, allowing smaller conductors and reduced energy losses.