Transformer Iron (Core) Loss

Piron = Physt + Peddy

Quick answer

This calculator solves Piron = Physteresis + Peddy-current for Core Loss. With Hysteresis Loss 22 W, Eddy-Current Loss 47 W, the result is 69 W. It solves in 3 directions, so you can enter the values you have and get the one you need.

Calculator

Core Loss (W)
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Formula

Piron = Physteresis + Peddy-current

Description

Iron or core loss is the power dissipated in the magnetic core itself, independent of load current. It has two parts: hysteresis loss, from the energy needed to repeatedly reverse the magnetic domains each cycle, and eddy-current loss, from circulating currents induced in the core. Iron loss is essentially constant whenever the transformer is energized, so it dominates the no-load and light-load efficiency.

Variables

  • Piron — Total core loss (W)
  • Physt — Hysteresis loss (W)
  • Peddy — Eddy-current loss (W)

Practical Notes

Laminating the core and using silicon steel or ferrite reduces eddy losses; choosing a low-coercivity material reduces hysteresis loss. Iron loss is measured by the open-circuit test.

Symbols and units

Symbol Meaning Default unit Accepted units
Piron Core Loss W µW, mW, W, kW
Physt Hysteresis Loss W µW, mW, W, kW
Peddy Eddy-Current Loss W µW, mW, W, kW

Step by step

  1. 1. What you know: Hysteresis Loss 22 W, Eddy-Current Loss 47 W
  2. 2. The relation: Piron = Physteresis + Peddy-current
  3. 3. Substitute: Physt = 22 W, Peddy = 47 W
  4. 4. Result: Core Loss = 69 W

Worked examples

Minimum range

Given: Hysteresis Loss 22 mW, Eddy-Current Loss 47 mW

Result: Core Loss = 69 mW

Low range

Given: Hysteresis Loss 0.22 W, Eddy-Current Loss 0.47 W

Result: Core Loss = 0.69 W

Typical

Given: Hysteresis Loss 22 W, Eddy-Current Loss 47 W

Result: Core Loss = 69 W

High range

Given: Hysteresis Loss 2.2 kW, Eddy-Current Loss 4.7 kW

Result: Core Loss = 6.9 kW

Maximum range

Given: Hysteresis Loss 22 kW, Eddy-Current Loss 47 kW

Result: Core Loss = 69 kW

Solving for each variable

Solve for Core Loss

Hysteresis Loss 22 mW, Eddy-Current Loss 47 mW → 69 mW

Solve for Hysteresis Loss

Core Loss 100 mW, Eddy-Current Loss 22 mW → 78 mW

Solve for Eddy-Current Loss

Core Loss 100 mW, Hysteresis Loss 47 mW → 53 mW

How Core Loss changes with Hysteresis Loss

Hysteresis Loss (input) Core Loss (result)
2.2 W 49.2 W
5.5 W 52.5 W
11 W 58 W
16.5 W 63.5 W
22 W 69 W
33 W 80 W
44 W 91 W
88 W 135 W
154 W 0.201 kW
0.22 kW 0.267 kW

The same result in other units

Unit Value
mW 69000
W 69
kW 0.069

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<p><a href="https://vbatpower.com/formulas/transformer-iron-loss/">Transformer Iron (Core) Loss</a> Calculator by vbatpower.com</p>

Frequently asked questions

How do you calculate Transformer Iron (Core) Loss?

Use Piron = Physteresis + Peddy-current. With Hysteresis Loss 22 W, Eddy-Current Loss 47 W, Core Loss works out to 69 W.

What is the formula for Transformer Iron (Core) Loss?

The formula is Piron = Physteresis + Peddy-current. Iron or core loss is the power dissipated in the magnetic core itself, independent of load current.

How do you find Hysteresis Loss when you know the other values?

Rearrange for Hysteresis Loss: with Core Loss 100 mW, Eddy-Current Loss 22 mW, Hysteresis Loss is 78 mW.

How do you find Eddy-Current Loss when you know the other values?

Rearrange for Eddy-Current Loss: with Core Loss 100 mW, Hysteresis Loss 47 mW, Eddy-Current Loss is 53 mW.

What units does Transformer Iron (Core) Loss use?

Core Loss is shown in mW, W, kW. Values are held in SI base units internally, so you can mix prefixes without converting by hand.

Related Concepts

All Magnetics & Transformers formulas →
Transformer EMF Equation Transformer VA Rating Transformer Voltage Regulation Transformer Current Ratio Transformer Copper Loss Transformer Iron (Core) Loss Transformer Turns-per-Volt Transformer Impedance Matching

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