1. What is the Motor kW to Amps Calculation?

This calculation determines the current drawn by a three-phase AC motor based on its power rating, supply voltage, power factor, and efficiency. It's essential for proper electrical system design and protection.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( I \) — Current in amperes (A)
• \( kW \) — Motor power in kilowatts
• \( V \) — Line-to-line voltage in volts
• \( PF \) — Power factor (0 to 1)
• \( Eff \) — Motor efficiency (0 to 1)

Explanation: The formula converts kW to watts (×1000), accounts for three-phase power (√3), and divides by voltage and the product of power factor and efficiency.

3. Importance of Current Calculation

Details: Knowing motor current is crucial for selecting proper wire sizes, circuit breakers, overload protection, and ensuring the electrical system can handle the load.

4. Using the Calculator

Tips: Enter motor power in kW, line-to-line voltage in volts, and typical power factor (0.8-0.95) and efficiency (0.85-0.95) values if unknown. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: Why is power factor important?
A: Power factor represents the phase difference between voltage and current. Lower PF means higher current for the same real power.

Q2: What's a typical efficiency value?
A: Standard motors are typically 85-95% efficient, with higher efficiency in larger motors.

Q3: Does this work for single-phase motors?
A: No, for single-phase use: \( I = \frac{kW \times 1000}{V \times PF \times Eff} \)

Q4: How accurate is this calculation?
A: It provides theoretical full-load current. Actual current may vary with load conditions.

Q5: What about motor starting current?
A: Starting current (inrush) is typically 5-7 times full-load current but brief in duration.