Power Systems Tools

Free power systems calculators — convert three-phase kW, kVA and hp to amps with power factor and star or delta values, with cable and motor tools next.

2 tools

3-Phase Power

Convert three-phase kW, kVA or motor hp to line current, or amps back to power, with power factor, kVAR and star or delta phase voltage and current.

Also in Power Systems

Tools from other categories tagged with Power Systems

Motor Torque

Find a motor's rated torque from kW or hp and rpm, or solve for power or speed, in N·m, lb·ft, lb·in and kgf·m, with gearbox output and pole speeds.

Why These Tools

Nameplates speak in kilowatts and horsepower while breakers and clamp meters speak in amps. On a three-phase supply the √3 between those two numbers is where most hand calculations go wrong. 3-Phase Power Calculator converts in both directions with the power factor included, returns kVA and kVAR alongside, and shows the voltage and current each winding sees in star or delta.

Motor Torque Calculator is listed here from Electrical Installation, since the motor is usually the load in question: it turns the same kW and rpm into shaft torque, through a gearbox if there is one. The rest of this page will cover what sits around that load: cable resistance, busbar and conduit sizing, star-delta starters, harmonics and battery banks.

Power Systems Tools