Transformer

Transformer Primary and Secondary Current Calculation: Formula, Example, and Diagrama

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Transformer Primary and Secondary Current Calculation: Formula, Example

Transformers are the backbone of power distribution systems. Whether you’re designing, analyzing, or studying transformers, it’s essential to know how to calculate transformer HV and LV side current accurately.

You’ll learn:

  • How to calculate transformer HV and LV side current?

  • Transformer primary and secondary current formula?

  • 3-phase transformer primary and secondary current calculation?

  • Transformer turns calculation formula?

  • Practical examples and diagrams?

  1. Transformer

Transformer Primary and Secondary Current Formula

Single-Phase Transformer Current Formula

The formula to calculate current on either side of a single-phase transformer is:

Primary Current (I₁) = Power (P) / Primary Voltage (V₁)  Secondary Current (I₂) = Power (P) / Secondary Voltage (V₂)

3-Phase Transformer Current Formula

For 3-phase transformers, use the following formula:

Primary Current (I₁) = Power (P) / (√3 × V₁)  Secondary Current (I₂) = Power (P) / (√3 × V₂)

Explanation of Variables:

  • P = Rated Power of the transformer (in VA or kVA)
  • V₁ = Voltage on the HV (primary) side
  • V₂ = Voltage on the LV (secondary) side
  • I₁ = Current on the primary side
  • I₂ = Current on the secondary side
  • √3 = 1.732 (for 3-phase systems)

Let’s go through a real-world example to understand how the calculation works.

Example:

A 3-phase transformer has the following ratings:

  • Power: 1000 kVA
  • Primary Voltage (HV): 11,000 V
  • Secondary Voltage (LV): 433 V

Calculate:

  • Transformer primary current
  • Transformer secondary current

Solution:

Using the 3-phase current formula:

Primary Current (HV side):

I₁ = 1,000,000 / (√3 × 11,000)  I₁ ≈ 52.48 A

Secondary Current (LV side):

I₂ = 1,000,000 / (√3 × 433)  I₂ ≈ 1333.5 A

Transformer Current and Turns Ratio Diagram

To visualize the flow of current and the winding ratio, refer to the diagram below:

Image Suggestion: Upload a diagram showing:

  • Primary (HV) and Secondary (LV) windings
  • Arrow showing current direction
  • Voltage and turns indicated as V₁, V₂ and N₁, N₂ respectively

Use an image with filename and alt tag:.

Transformer Turns Calculation Formula

To find the number of turns on the secondary coil, use the turns ratio formula:

Formula:

V₁ / V₂ = N₁ / N₂

Where:

  • V₁ = Primary voltage
  • V₂ = Secondary voltage
  • N₁ = Number of primary turns
  • N₂ = Number of secondary turns

Example:

If a transformer has:

  • N₁ = 2200 turns
  • V₁ = 11,000 V
  • V₂ = 433 V

Then:

N₂ = (2200 × 433) / 11,000  N₂ ≈ 87 turns

This shows the transformer turns calculation formula in practice.

Transformer Current Calculator (Manual Method)

You can manually calculate the transformer current using these formulas:

For Single-Phase Transformers:

I = P / V

For 3-Phase Transformers:

I = P / (√3 × V)

These formulas act as a transformer primary and secondary current calculator when used with known transformer ratings.

Summary Table of Transformer Calculation Formulas

Calculation Type Formula
Single-phase current (primary or secondary) I = P / V
3-phase current (primary or secondary) I = P / (√3 × V)
Turns ratio formula V₁ / V₂ = N₁ / N₂

Use this table as a quick reference for transformer current and turns ratio calculations.

Conclusion

Understanding how to calculate transformer HV and LV side current is vital for engineers, electricians, and students alike. By applying the correct transformer primary and secondary current formula and using the turns calculation formula, you can:

  • Size transformers accurately
  • Design safe and efficient systems
  • Verify transformer performance in real time

This guide also serves as a transformer secondary current calculator and a resource for understanding the turns ratio between windings. Bookmark this page and refer back whenever you’re working with transformer ratings and current calculations.

Key Learning :

  1. How to calculate transformer HV and LV side current

  2. Transformer primary and secondary current formula

  3. Transformer primary current formula

  4. 3 phase transformer primary and secondary current calculation

  5. Transformer primary and secondary current calculator

  6. Transformer primary and secondary current formula example

  7. Transformer secondary current formula

  8. Transformer calculation formula

  9. Transformer secondary current calculator

  10. Transformer turns calculation formula

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