Motors, Generators & Electrification Equipment worked example

Copper Fill Factor at 48% target slot copper fill factor: a worked example

Push target slot copper fill factor up to 48% and the picture changes. This example computes every intermediate figure at that operating point. Use it when you need a clean copper fill percentage and gap to target for a stator slot design or winding review.

The inputs for this scenario

  • Net copper conductor area in the slot: 100 mm² (unchanged)
  • Total stator slot cross-section area: 250 mm² (unchanged)
  • Target slot copper fill factor: 48 % (raised for this scenario; the documented default is 42)

Working through the calculation

  • Applying the documented formula (Copper fill factor = copper conductor area in slot ÷ total slot area × 100) to the inputs above produces each figure below.
  • At this operating point the engine returns 40 % for copper fill factor, the number this scenario is built around.
  • At this operating point the engine returns 8 points for fill factor gap to target.
  • At this operating point the engine returns 100 count for copper conductor area in slot.
  • At this operating point the engine returns 250 count for total slot area.

How this compares with the baseline

  • Against the tool's baseline example, where target slot copper fill factor sits at 42% and the headline result is 40 %, this scenario lands almost exactly on the baseline at 40 %.
  • It computes the percentage of total slot area filled by copper conductor and reports the point gap between that achieved fill and your target. The value of this scenario is the size of the gap it exposes: that gap, priced out over a year, is the budget you can justify spending to close it.

Results at a glance

  • Copper fill factor: 40 % (headline result)
  • Fill factor gap to target: 8 points
  • Copper conductor area in slot: 100 count
  • Total slot area: 250 count

Run it with your numbers

  • Every input above is editable in the live Copper Fill Factor calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.