Transformer Turns Ratio
Compute turns ratio and secondary current I2 from primary/secondary voltages V1/V2 and primary current I1.
Inputs
Formula
Fundamentals
Compute turns ratio and secondary current I2 from primary/secondary voltages V1/V2 and primary current I1.
This tool computes Transformer Turns Ratio from the formula: k = V2/V1 = N2/N1; I2 = I1/k
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
| Primary V1 | Input parameter |
| Secondary V2 | Input parameter |
| Primary I1 | Input parameter |
| Ratio k | Output result |
| Secondary I2 | Output result |
How to use
- Fill in Primary V1, Secondary V2, Primary I1 in the Inputs section (watch the unit on each field).
- Click Calculate; the tool evaluates the formula shown above.
- Read Ratio k, Secondary I2 in the results area.
Formula · Worked Example · Knowledge
Formula
核心计算关系：k = V2/V1 = N2/N1; I2 = I1/k
输入变量：
- Primary V1
V1— V - Secondary V2
V2— V - Primary I1
I1— A
输出结果：
- Ratio k
k - Secondary I2
I2— 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 k = V2/V1 = N2/N1; I2 = I1/k，取 Primary V1 = 220 V；Secondary V2 = 24 V；Primary I1 = 2 A。
代入计算得：Ratio k = 0.1091；Secondary I2 = 18.33 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 |
|---|---|---|---|
| Primary V1 (V) | V1 | V | 220 |
| Secondary V2 (V) | V2 | V | 24 |
| Primary I1 (A) | I1 | A | 2 |
Outputs
| Result | Symbol | Unit |
|---|---|---|
| Ratio k | k | |
| Secondary I2 | I2 | A |
Applications
- Common engineering use cases