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Transformers and Power Supplies

Transformer Copper Loss Calculator

Transformer Copper Loss estimates copper loss from the visible inputs and keeps the assumptions close to the number.

Set up the Transformer Copper Loss case

Document whether winding current and the other entries are measured, rated, assumed, or calculated.

A

Enter winding current in A.

Ω

Enter winding resistance in Ω.

Set up Transformer Copper Loss carefully

The setup starts with Winding current, and Winding resistance. Keep those entries on one unit basis before the formula is evaluated.

loss = I²R
  • Winding current: 10 A in the sample case.
  • Winding resistance: 0.18 Ω in the sample case.

What copper loss means here

This worksheet is for calculate copper loss from winding current and winding resistance. The answer is easier to trust when the entered values describe the same equipment, period, and operating condition.

Transformer Copper Loss depends on topology, duty cycle, thermal path, ripple, and input voltage range.

If two cases differ in winding current, save them as separate runs. A blended entry can hide the reason the copper loss changed.

If the next step shifts toward Autotransformer Rating, keep that as a separate worksheet instead of forcing the numbers into Transformer Copper Loss.

Using the Transformer Copper Loss answer

Read copper loss together with the input values, not as a standalone fact. The same number can imply different decisions under a different equipment rating or operating period.

Changing winding current while leaving winding resistance fixed is a useful way to see which assumption controls the answer.

If the next step shifts toward Transformer Core Loss, keep that as a separate worksheet instead of forcing the numbers into Transformer Copper Loss.

Testing winding current

Using the sample values, Winding current = 10 A; Winding resistance = 0.18 Ω, the primary result is 18.00 W.

Baseline18.00 W
Change Winding current11.5 A
New result23.80 W

This Transformer Copper Loss one-input test is a scale check, showing direction and sensitivity without turning the changed case into a recommendation.

If the changed winding resistance comes from a real measurement, keep the original Transformer Copper Loss run so the source of the difference remains clear.

Checks outside Transformer Copper Loss

Winding resistance rises as the transformer warms.

  • Ripple current
  • Minimum load behavior
  • Core saturation

A numerically valid Transformer Copper Loss result can still be wrong if the field condition, connection type, tariff period, or equipment rating does not match.

When your notes point to Boost Converter, open it after saving this baseline so the two cases do not get mixed.

Before saving copper loss

Which value should be rounded first?

Keep winding resistance at source precision during Transformer Copper Loss; round copper loss only where presentation or purchasing requires it.

Can the default values be used as a recommendation?

No. The Transformer Copper Loss defaults only demonstrate the form. Replace them with measured or rated values for the actual transformers and power supplies case.