kW (kilowatt) is a unit of power, and A (ampere) is a unit of current. They cannot be directly converted; a connection must be established through voltage (V) and power factor (PF).
Basic Relationship Formula
The basic relationship between power (P), voltage (U), and current (I) is:
P = U × I (Power = Voltage × Current)
From this formula, the following can be derived:
I = P / U (Current = Power / Voltage)
P = I × U (Power = Current × Voltage)
Specific Conversion Formulas
- DC (Direct Current) Circuits
A = (kW × 1000) / V
– Example: For a power of 1 kW and a voltage of 100 V, the current I = (1×1000)/100 = 10 A
- AC (Alternating Current) Single-Phase Circuits
A = (kW × 1000) / (V × PF)
– PF (Power Factor): The ratio of real power to apparent power in an AC circuit, ranging from 0 to 1.
– Example: For a power of 1 kW, a voltage of 220 V, and PF = 0.8, the current I = (1×1000)/(220×0.8) ≈ 5.68 A
- AC (Alternating Current) Three-Phase Circuits
A = (kW × 1000) / (V × √3 × PF)
– √3 ≈ 1.732
– Example: For a power of 10 kW, a voltage of 380 V, and PF = 0.9, the current I = (10×1000)/(380×1.732×0.9) ≈ 16.99 A
Why Direct Conversion Is Not Possible?
kW measures the rate of energy conversion, while A measures the rate of charge flow—they describe different physical quantities.
– 1 kW = 1000 W = 1000 V·A (1 kilowatt = 1000 watts = 1000 volt-amperes)
– For the same power, the higher the voltage, the lower the current, and vice versa.
Practical Conversion Examples
| Scenario | Formula | Example Calculation |
| Household Appliances (Single-Phase 220 V) | A = (kW × 1000)/(220 × 0.8) | 2 kW Air Conditioner: (2×1000)/(220×0.8) ≈ 11.36 A |
| Industrial Equipment (Three-Phase 380 V) | A = (kW × 1000)/(380 × 1.732 × 0.9) | 15 kW Motor: (15×1000)/(380×1.732×0.9) ≈ 25.3 A |
| Car Battery (12 V DC) | A = (kW × 1000)/12 | 1.2 kW Inverter: (1.2×1000)/12 = 100 A |
Summary
The relationship between kW and A is determined by the formula P = U × I. To convert between them, you must know the voltage and (for AC circuits) the power factor.
Remember: Power = Voltage × Current—this is a fundamental formula for understanding electrical systems.
