# @stem_antics on Instagram

- **Type:** Video
- **Original URL:** https://www.instagram.com/p/DZgJ08PSqMr
- **Gondola URL:** https://gondola.cc/posts/66591647-stem-antics-instagram
- **Thumbnail:** https://img.gondola.cc/tr:w-,h-,fo-auto/postThumbnails/f544c2515f.jpg
- **Posted:** 2026-06-12T22:24:58.000+00:00
- **Account Owner:** Stem Antics (@stem_antics) — https://gondola.cc/stem_antics

## Caption

A 2-megawatt traction motor and the cooling fan in a server rack share the same physics, but almost nothing about how they’re built. Scaling electric motor production is less about magnetic design and more about turning that design into something a stamping press, a winding head, and an impregnation tank can reproduce thousands of times a day.

The bottleneck is almost always the laminations. Motors run on thin sheets of non-oriented electrical steel, typically 0.2 to 0.5 mm thick, stamped and stacked to suppress eddy currents. At scale this means:

	•	Progressive dies running at 200+ strokes per minute, holding tolerances under 10 microns
	•	Interlocking or laser-welded stacks that hold the core without adhesive
	•	Annealing to restore the magnetic permeability lost to punch-shock stress

Then comes the copper. Hairpin winding has largely displaced randomly wound coils in EV traction motors because rectangular bar conductors pack the slot far tighter. Slot fill jumps from roughly 45% to over 70%, cutting resistive losses hard. But every hairpin must be bent, inserted, twisted, and laser-welded at hundreds of joints per stator, all without nicking the enamel insulation.

Squirrel-cage rotors get their conductors die-cast straight into the lamination stack. Molten aluminum, or increasingly copper, is injected under pressure to form the bars and end rings in a single shot.

Everything then gets vacuum-pressure impregnated with resin, cured, balanced to within grams at thousands of RPM, and run through back-EMF and surge tests before it ships.

The magnetic design is elegant. The manufacturing is brutal repeatability at micron scale.

#stemantics #electricmotors #manufacturing #engineering #emobility

## Stats

- **Views:** 7,037
- **Likes:** 306
- **Shares:** 0
- **Comments:** 5

## Tags

engineering, emobility, manufacturing, electricmotors, stemantics

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