Three-phase Power
Compute three-phase active power P from line voltage V, line current I and power factor cosφ.
Inputs
Formula
P = √3·V·I·cosφ
Basis for motor power rating and wiring.
Fundamentals
Compute three-phase active power P from line voltage V, line current I and power factor cosφ.
This tool computes Three-phase Power from the formula: P = √3·V·I·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
| Line voltage V | Input parameter |
| Line current I | Input parameter |
| Power factor cosφ | Input parameter |
| Active power P | Output result |
How to use
- Fill in Line voltage V, Line current I, Power factor cosφ in the Inputs section (watch the unit on each field).
- Click Calculate; the tool evaluates the formula shown above.
- Read Active power P in the results area.
Formula · Worked Example · Knowledge
Formula
核心计算关系：P = √3·V·I·cosφ
输入变量：
- Line voltage V
V— V - Line current I
I— A - Power factor cosφ
pf
输出结果：
- Active power P
P— kW
假设/适用：Gearing/thread formulas assume standard, zero-backlash mounting; include error & load factors K_A.
Worked Example
根据公式 P = √3·V·I·cosφ，取 Line voltage V = 400 V；Line current I = 20 A；Power factor cosφ = 0.85。
代入计算得：Active power P = 11.78 kW。
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 |
|---|---|---|---|
| Line voltage V (V) | V | V | 400 |
| Line current I (A) | I | A | 20 |
| Power factor cosφ | pf | 0.85 |
Outputs
| Result | Symbol | Unit |
|---|---|---|
| Active power P | P | kW |
Applications
- Common engineering use cases
FAQ
What formula does this tool use?
This tool computes per ISO / AGMA / ASME standard formulas: P = √3·V·I·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