Cable Voltage Drop
Estimate single-phase cable voltage drop ΔV from current I, length L and R per km (Ω/km).
Inputs
Formula
ΔV = 2·I·L·Rkm/1000
Excess drop needs larger cross-section or shorter run.
Fundamentals
Estimate single-phase cable voltage drop ΔV from current I, length L and R per km (Ω/km).
This tool computes Cable Voltage Drop from the formula: ΔV = 2·I·L·Rkm/1000
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
| Current I | Input parameter |
| Length L | Input parameter |
| R per km | Input parameter |
| Voltage drop ΔV | Output result |
How to use
- Fill in Current I, Length L, R per km in the Inputs section (watch the unit on each field).
- Click Calculate; the tool evaluates the formula shown above.
- Read Voltage drop ΔV in the results area.
Formula · Worked Example · Knowledge
Formula
核心计算关系：ΔV = 2·I·L·Rkm/1000
输入变量：
- Current I
I— A - Length L
L— m - R per km
Rkm— Ω/km
输出结果：
- Voltage drop ΔV
dV— V
假设/适用：Gearing/thread formulas assume standard, zero-backlash mounting; include error & load factors K_A.
Worked Example
根据公式 ΔV = 2·I·L·Rkm/1000，取 Current I = 20 A；Length L = 50 m；R per km = 12.1 Ω/km。
代入计算得：Voltage drop ΔV = 24.2 V。
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 |
|---|---|---|---|
| Current I (A) | I | A | 20 |
| Length L (m) | L | m | 50 |
| R per km (Ω/km) | Rkm | Ω/km | 12.1 |
Outputs
| Result | Symbol | Unit |
|---|---|---|
| Voltage drop ΔV | dV | V |
Applications
- Common engineering use cases
FAQ
What formula does this tool use?
This tool computes per ISO / AGMA / ASME standard formulas: ΔV = 2·I·L·Rkm/1000
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