Guides: 3-phase

Three-phase power systems are the standard for industrial applications. These guides explain how 3-phase power works, how to calculate it, and when to use it in your electrical designs.

About This Topic

Three-phase power systems are the standard for industrial applications. These guides explain how 3-phase power works, how to calculate it, and when to use it in your electrical designs.

Recommended Learning Path

  1. Learn the fundamentals of 3-phase power systems
  2. Understand voltage relationships and phase angles
  3. Calculate current, power, and kVA for 3-phase loads
  4. Apply 3-phase calculations to motor and equipment sizing
  5. Explore power factor and efficiency considerations

Related Calculators

Use these professional calculators to apply the concepts covered in the 3-phase guides:

3-Phase Power Calculator

Calculate three-phase current, kW, and kVA for industrial electrical systems.

Use Tool

Factory Load Calculator

Determine total electrical load, current, and breaker ratings for industrial facilities.

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Transformer Size Calculator

Calculate recommended transformer kVA rating based on load and power factor.

Use Tool

All Articles

Browse all 8 guides covering 3-phase topics:

3 Phase Power Explained: Wye vs Delta, 120° & Uses

What is 3-phase power? Learn 120° phases, line vs phase voltage, wye/delta & why factories use it—not a calculator; links to formula guide.

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3 Phase Power & Current Formula (√3·V·I·PF) + Examples

3-phase power & current: kW=√3·V·I·PF, motor FLA from HP, 208–480 V current presets. Free examples—verify with the calculator.

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3-Phase PF: Clamp Meter Measurement Steps (True vs Displacement)

How to measure 3-phase power factor with a clamp meter or analyzer—true vs displacement PF, field steps & examples. Free guide; verify with kW→kVA tool.

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3-Phase Unbalanced Load Formula (% + Causes & Fixes)

Unbalanced load in 3-phase systems: % formula, causes, and correction steps. Free worked example—verify currents with the 3-phase power calculator.

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OLTC vs OCTC: Difference & 13.8 kV Cost

OLTC vs OCTC difference: outage rules and 13.8 kV cost example. Free decision table—when on-load tap changers pay off; full forms link to the tap changer guide.

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Voltage Regulation Formula (%VR = (Vnl−Vfl)/Vfl×100)

Voltage regulation formula: %VR = (Vnl − Vfl) ÷ Vfl × 100%. Free 480 V transformer example—then size kVA or check taps.

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kVA Formula 3-Phase (√3 × V × I) + Examples

kVA formula 3-phase: kVA = √3×V×I÷1000 with 400/480 V examples. Free—then verify with the transformer size calculator.

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Transformer Tap Changer Faults (OLTC & OCTC)

Identify and prevent common transformer tap changer faults. Free OLTC/OCTC symptoms, causes, and maintenance checklist for 3-phase units.

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