By Dwight Chestnut
Updated Mar 24, 2022

In electrical engineering, power measured in kilowatts (kW) is the product of current (amps) and voltage (volts) applied to a load. While power distribution utilities typically supply energy in kilovolt‑amperes (kVA), the usable portion—actual power consumed by a device—depends on the load’s power factor and is expressed in watts or kilowatts.

Step 1: Identify the Current

Begin by determining the current, I, you wish to convert. For example, suppose I = 40 A.

Step 2: Set Up Measurement Equipment

Connect a suitable power supply capable of delivering the specified current to the load. Place a voltmeter in parallel with the supply and load so you can record the voltage simultaneously.

Step 3: Measure Voltage

Power the supply to deliver the current to the load and note the voltage reading. In this example, let the measured voltage be V = 280 V.

Step 4: Calculate Three‑Phase Power

Use the three‑phase power formula:

kW = √3 × V × I

Substituting the example values:

kW = √3 × 280 V × 40 A ≈ 19.4 kW

Required Equipment

• Power supply (capable of the desired current)
• Voltmeter (for accurate voltage measurement)