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ENGINEERING CALCULATORS

Single / three-phase motor current calculator

Engineering calculators (Beta)

Convert shaft output, efficiency and power factor into AC input power and current.

Inputs

Choose units and enter numbers. Full-width digits and fractions such as 1/8 or 1 3/8 are accepted. Changing a unit converts the entered value.

Results

Reference calculation only. Results do not certify suitability for an actual design or its safety.

Diagram

Inputs: select a blue symbol to edit Results: red-orange values and lines

Formula and applicability

Pin = Pout/η; S = Pin/cosφ; I = S/U (single), S/(√3 U) (three phase)

Displayed values are rounded. Diagrams illustrate the calculation conditions. Initial material and fluid properties are examples; replace them with values for the actual material, temperature and conditions.

Reference
Using this information as a reference

Equations assume particular loads, supports and deformation ranges. Check inputs, units and the applicability of each equation. Diagrams explain conditions; they are not manufacturing drawings or proof of safety.

Material values are typical values or reference ranges, not certified product properties or ready-to-use design allowables. They vary with standards, product form, dimensions, temper and temperature. Check the specifications and inspection certificates for the actual product.

Displayed safety factors and checks apply only to the supplied inputs and calculation model. They do not automatically establish the safety of a complete design, including code compliance, service life, fatigue or joints. For actual design, manufacture and use, separately verify applicable regulations and standards, product specifications, and the necessary tests and engineering review.

この計算で求められること

軸出力・効率・力率から、交流の入力電力と電流を求めます。

入力・結果・適用条件を確認する

選択した形状・計算方法により、使う項目は変わります。実際の計算は上の図と入力欄で行えます。

主な入力

  • 電源方式 (—)
  • 必要な機械軸出力 Pout (kW / W / mW)
  • 線間電圧 U(単相は端子間) (V / kV / µV)
  • モーター効率 η (% / fraction / ‰)
  • 力率 cosφ (% / fraction / ‰)

得られる結果

  • 有効入力電力 (kW)
  • 皮相電力 (kVA)
  • 無効電力(遅れ) (kvar)
  • 線電流 (A)
  • モーター損失の計算値 (W)

計算式の概要

Pin = Pout/η; S = Pin/cosφ; I = S/U (single), S/(√3 U) (three phase)

正弦波・定常負荷、三相は平衡負荷です。始動電流・高調波・インバーター入力・不平衡・保護装置・電線容量の選定は対象外です。

現在選択中の方法には、操作欄の「計算式・適用条件」を使ってください。参考計算であり、設計全体の安全性を保証するものではありません。

関連する計算

What this calculator does

Convert shaft output, efficiency and power factor into AC input power and current.

Inputs, outputs and applicability

The selected model determines which of these inputs and outputs apply. Use the working diagram and input panel above to calculate.

Inputs

  • Supply arrangement (—)
  • Required mechanical shaft output Pout (kW / W / mW)
  • Line voltage U (terminal voltage for single phase) (V / kV / µV)
  • Motor efficiency η (% / fraction / ‰)
  • Power factor cosφ (% / fraction / ‰)

Calculated results

  • Active input power (kW)
  • Apparent power (kVA)
  • Reactive power (lagging) (kvar)
  • Line current (A)
  • Calculated motor loss (W)

Formula overview

Pin = Pout/η; S = Pin/cosφ; I = S/U (single), S/(√3 U) (three phase)

Sinusoidal steady loads; balanced loads for three-phase supply. Starting current, harmonics, inverter input, imbalance, protective devices and cable ampacity selection are excluded.

The displayed formula and conditions in the working panel apply to the currently selected model. Reference calculation only; it does not certify a complete design.

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