Transformers and Power Supplies
Transformer Core Loss Calculator
Transformer Core Loss provides a checkable estimate of core loss. It is intended for scenario comparison, not as automatic approval of a component or installation.
Run the Transformer Core Loss scenario
Do not mix values recorded under different conditions.
Input notes
Use voltage and current values from the same side of the transformer or converter. Do not combine a worst-case value with unrelated nominal data.
Check every prefix before entry; micro, milli, kilo, and mega are not interchangeable. For capacity remaining, use Battery Self-Discharge Calculator.
- No-load input power
- Default example: 32 W. Enter no-load input power in W.
- No-load copper loss
- Default example: 3 W. Enter no-load copper loss in W.
Understanding the equation
The displayed result follows core loss ≈ no-load power − copper loss. Only No-load input power and No-load copper loss enter the numerical result.
Using the loaded examples gives 29.00 W. Your saved case should identify where each entry came from.
Calculate core loss from no-load input power and no-load copper loss. If you also need copper loss, continue with Transformer Copper Loss Calculator.
Reading Core loss
Interpret Core loss on the same basis used for the source values. Compare it with a no-load, nominal-load, and limiting-load case.
Keep the input set beside the output so another reader can reproduce it. Current Transformer Burden Calculator covers the related CT burden step.
Using the answer downstream
Record no-load input power and no-load copper loss with core loss. Include the operating state and data source.
Carry core loss at its stored precision for dependent calculations. Round at the final reporting step.
Where this estimate can fail
Instrumentation error matters at low power factor.
Depending on the application, account for diode loss, ESR, regulation, ripple current, and thermal resistance. Use measurements, manufacturer data, or another calculation for effects that can change the decision.
Use voltage and current values from the same side of the transformer or converter. For the companion primary current calculation, open Current Transformer Ratio Calculator.
Before carrying the answer forward
Check the source of no-load copper loss before calculating. A credible result requires every field to describe the same physical condition and unit basis.
After calculating core loss, compare its magnitude with voltage stress, current stress, ripple, loss, regulation, and temperature. An independent order-of-magnitude check can reveal a misplaced decimal or unit prefix.
Document any effect handled outside this page, especially isolation, creepage, waveform shape, and manufacturer operating limits. That note prevents a later reader from assuming the simple equation covered it.
Questions about Transformer Core Loss
How do I run a useful sensitivity check?
Keep unaffected entries fixed so the cause of the difference remains visible. Record waveform, frequency, load level, and winding or device temperature.