Question

What is the formula for kW?

Answer 1

The formula to calculate kilowatts (kW) depends on whether you're working with electrical power in an AC or DC system. Here are the formulas for both:

### 1. For DC (Direct Current):
\[ \text{Power (kW)} = \frac{V \times I}{1000} \]

Where:
- \( V \) = Voltage in volts
- \( I \) = Current in amperes
- Divide by 1000 to convert watts (W) to kilowatts (kW)

### 2. For AC (Alternating Current):
For single-phase AC, the formula is:
\[ \text{Power (kW)} = \frac{V \times I \times \cos(\theta)}{1000} \]

Where:
- \( V \) = Voltage in volts
- \( I \) = Current in amperes
- \( \cos(\theta) \) = Power factor (which accounts for the phase difference between voltage and current)

For three-phase AC, the formula is:
\[ \text{Power (kW)} = \frac{\sqrt{3} \times V \times I \times \cos(\theta)}{1000} \]

Where:
- \( V \) = Line-to-line voltage in volts
- \( I \) = Current in amperes
- \( \cos(\theta) \) = Power factor

So, the key point is:
- \( kW \) = Power in kilowatts
- \( V \) = Voltage
- \( I \) = Current
- \( \cos(\theta) \) = Power factor (only for AC)

These formulas give you the electrical power in kilowatts for DC and AC systems!