Electrical Reference
Three-Phase Formulas
Power, current, voltage, power factor, and efficiency relationships.
Use line-to-line voltage and the √3 factor for balanced three-phase power relationships.
Core relationships
- kVA = √3 × V × I ÷ 1,000.
- kW = kVA × power factor.
- Motor output estimate also includes efficiency.
Inputs
- Confirm line-to-line voltage, balanced current, power factor, and whether values are RMS.
Common mistakes
- Mixing line-to-neutral and line-to-line voltage.
- Omitting power factor or efficiency.
Verify
- Compare calculated power to nameplate and measured phase balance.