Three-phase Current
Compute line current I from active power P (kW), line voltage V and cosφ.
Inputs
Formula
I = P/(√3·V·cosφ)
Used to size breakers and cable cross-section.
Fundamentals
Compute line current I from active power P (kW), line voltage V and cosφ.
This tool computes Three-phase Current from the formula: I = P/(√3·V·cosφ)
History
Design theory of gears, threads and bearings matured with machine tools and standardisation (AGMA, ISO) since the Industrial Revolution.
Engineering applications
Used for transmission design, joint strength checks and component selection.
Glossary
| Active power P | Input parameter |
| Line voltage V | Input parameter |
| Power factor cosφ | Input parameter |
| Line current I | Output result |
How to use
- Fill in Active power P, Line voltage V, Power factor cosφ in the Inputs section (watch the unit on each field).
- Click Calculate; the tool evaluates the formula shown above.
- Read Line current I in the results area.
Formula · Worked Example · Knowledge
Formula
核心计算关系：I = P/(√3·V·cosφ)
输入变量：
- Active power P
P— kW - Line voltage V
V— V - Power factor cosφ
pf
输出结果：
- Line current I
I— A
假设/适用：Gearing/thread formulas assume standard, zero-backlash mounting; include error & load factors K_A.
Worked Example
根据公式 I = P/(√3·V·cosφ)，取 Active power P = 10 kW；Line voltage V = 400 V；Power factor cosφ = 0.85。
代入计算得：Line current I = 16.98 A。
Key Points
- Gearing/thread formulas assume standard, zero-backlash mounting; include error & load factors K_A.
- Compare stress with allowable stress and keep a safety factor (≥1.5, ≥2 for critical parts).
- For high speed/load also check lubrication, heat and fatigue life, not just static strength.
Parameters
Inputs
| Parameter | Symbol | Unit | Default |
|---|---|---|---|
| Active power P (kW) | P | kW | 10 |
| Line voltage V (V) | V | V | 400 |
| Power factor cosφ | pf | 0.85 |
Outputs
| Result | Symbol | Unit |
|---|---|---|
| Line current I | I | A |
Applications
- Common engineering use cases
FAQ
What formula does this tool use?
This tool computes per ISO / AGMA / ASME standard formulas: I = P/(√3·V·cosφ)
How accurate are the results?
Results match input precision, based on SI units and common engineering approximations; for critical duty re-check with a safety factor.
Where is it used?
Common engineering use cases