{"id":74017,"date":"2025-09-02T16:35:53","date_gmt":"2025-09-02T08:35:53","guid":{"rendered":"https:\/\/xometry.asia\/?p=74017"},"modified":"2025-09-02T16:35:56","modified_gmt":"2025-09-02T08:35:56","slug":"exploring-magnetic-couplings-no-gears-no-belts-just-magnets","status":"publish","type":"post","link":"https:\/\/staging-wp.xometry.asia\/en\/exploring-magnetic-couplings-no-gears-no-belts-just-magnets\/","title":{"rendered":"Exploring Magnetic Couplings: No Gears, No Belts, Just Magnets"},"content":{"rendered":"\n

What if I told you I could spin a propeller without touching it? No gears. No belts. Nothing but magnets. Sounds like science fiction, right? I\u2019m Emiel, The Practical Engineer \u2014 you might know me from my last project, the booster backpack. This time, I dove into magnetic couplings, and what I discovered honestly surprised me.<\/p>\n\n\n\n

\"Practical<\/figure>\n\n\n\n

As an aerospace engineering graduate with a passion for hands-on design, I spend most of my time experimenting and building functional things. Through my YouTube channel<\/a>, I share engineering challenges like this one to inspire others to get creative and start building themselves.<\/p>\n\n\n\n

Why Build a Motor With No Contact?<\/strong><\/h2>\n\n\n\n

I\u2019d heard of magnetic couplings before, mainly in the context of stirrers at the bottom of lab beakers, where the spinning magnetic field drives a tiny bar in a sealed container. But I had never built one myself.<\/p>\n\n\n\n

It seemed like the perfect hands-on challenge: how strong and functional could these non-contact connections actually be? Could I spin a shaft with nothing but magnetic force \u2014 and could I control it?<\/p>\n\n\n\n

As I was researching different setups, I stumbled upon a curious variant that didn\u2019t rely on a second magnet at all. Instead, it used a solid copper plate and rotating magnets to generate motion. That\u2019s when the real excitement began.<\/p>\n\n\n\n

This setup makes use of eddy currents \u2014 swirling loops of electric current induced in conductors, which in turn generate opposing magnetic fields. It\u2019s the same principle behind magnetic braking in roller coasters or high-speed trains.<\/p>\n\n\n\n

My goal was simple: build both versions, test them, and get a feel for the forces involved.<\/p>\n\n\n\n

<\/p>\n\n\n\n

From CAD Sketch to Copper and Magnets<\/strong><\/h2>\n\n\n\n

Everything started as a sketch in Fusion 360. I modeled two rotating disks, each holding six neodymium magnets in alternating polarity: north pole up on one disk, south pole up on the other. The idea was that when one disk spun, magnetic forces would transfer that motion to the other.<\/p>\n\n\n\n

\"CAD<\/p>\n\n\n\n

CAD model of the copper disk, designed in Fusion 360 to interact with the magnetic coupling.\u00a9<\/p>\n\n\n\n

\"The<\/figure>\n\n\n\n

I 3D printed the housings using my Bambu Lab printers and sourced the copper plates from Xometry. <\/p>\n\n\n\n

Version 1: Magnet vs Magnet<\/strong><\/h3>\n\n\n\n

This version used two identical magnetic disks placed face to face. When one disk spun, the magnetic field pulled the second one into rotation with it. The coupling was surprisingly strong and extremely responsive.<\/p>\n\n\n\n

\"Aligning
Aligning the magnet disks during assembly \u2014 alternating poles create the magnetic link.\u00a9<\/figcaption><\/figure>\n\n\n\n
\"Assembling
Assembling the magnetic coupler \u2014 magnets face each other in alternating polarity.\u00a9<\/figcaption><\/figure>\n\n\n\n

<\/p>\n\n\n\n

However, the connection was rigid, too rigid. If anything jammed or encountered resistance, the entire system halted. There was no slip, which is great for torque transfer, but not ideal in applications where flexibility or safety is needed.<\/p>\n\n\n\n

Version 2: Magnet vs Copper Plate<\/strong><\/h3>\n\n\n\n

This is where it got really exciting. When I spun the magnetic disk near the copper plate, the plate started to rotate, without touching anything. That\u2019s the magic of eddy currents in action.<\/p>\n\n\n\n

\"Though<\/figure>\n\n\n\n

Though copper isn\u2019t magnetic, the falling magnet slows slightly as eddy currents create resistance just before contact.\u00a9<\/p>\n\n\n\n

It felt like turning a paddle through honey. The connection was smooth, resistant, and self-regulating. The faster the magnets moved, the stronger the induced currents and torque. The closer the magnets were to the plate, the more force they could transfer.<\/p>\n\n\n\n

\"The
The copper plate begins spinning \u2014 driven only by the magnetic field and eddy currents.\u00a9<\/figcaption><\/figure>\n\n\n\n

Too far, and the coupling weakened. Too close, and the system tried to pull itself forward. The effect was surprisingly strong \u2014 even with a gap of over 8mm, the interaction still worked.<\/p>\n\n\n\n

One thing that amazed me: the copper setup also worked in reverse. When I spun the copper plate, it started rotating the magnet disk. I didn\u2019t expect that.<\/p>\n\n\n\n

I even tried different thicknesses \u2014 a 6mm plate versus a 3mm one. The thinner one responded faster, likely due to its lower inertia.<\/p>\n\n\n\n

Real-World Potential<\/strong><\/h2>\n\n\n\n

Could this have real-world applications? Definitely. <\/p>\n\n\n\n

Think about situations where you need to drive a shaft through a sealed wall \u2014 for example, in chemical processing, underwater systems, or food production lines. These environments benefit from non-contact torque transfer, since there\u2019s no risk of contamination or leaks.<\/p>\n\n\n\n

The copper version\u2019s natural slip could even act as a safety feature \u2014 providing soft starts or disengaging when overloaded.<\/p>\n\n\n\n

What\u2019s Next?<\/strong><\/h2>\n\n\n\n

If I build a next version, I\u2019d design a system that lets me adjust the spacing between the magnet disk and the copper plate on the fly. That way, I could fine-tune the amount of torque transferred.<\/p>\n\n\n\n

I\u2019d also like to try out different magnet configurations or materials, maybe even turn this into a real-world application.<\/p>\n\n\n\n

For now, I\u2019m just glad I gave the copper version a shot \u2014 even though I didn\u2019t believe in it at first. Turns out, sometimes the best results come from the ideas you doubt the most.<\/p>\n\n\n\n

\n\n\n\n

Want to see it in action? Check out the full video on my channel.\u00a0<\/strong>And if you\u2019ve got an idea for where magnetic couplings could be useful, I\u2019d love to hear from you.<\/p>\n","protected":false},"excerpt":{"rendered":"

Emiel explores magnetic couplings using Xometry copper plates and 3D-printed housings, achieving contactless torque transfer.<\/p>\n","protected":false},"author":37,"featured_media":73853,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[36,735],"tags":[],"class_list":["post-74017","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-customer-stories","category-innovation-stories-en"],"acf":[],"publishpress_future_action":{"enabled":false,"date":"2026-09-13 20:09:30","action":"change-status","newStatus":"draft","terms":[],"taxonomy":"category","extraData":[]},"publishpress_future_workflow_manual_trigger":{"enabledWorkflows":[]},"_links":{"self":[{"href":"https:\/\/staging-wp.xometry.asia\/en\/wp-json\/wp\/v2\/posts\/74017","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/staging-wp.xometry.asia\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/staging-wp.xometry.asia\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/staging-wp.xometry.asia\/en\/wp-json\/wp\/v2\/users\/37"}],"replies":[{"embeddable":true,"href":"https:\/\/staging-wp.xometry.asia\/en\/wp-json\/wp\/v2\/comments?post=74017"}],"version-history":[{"count":0,"href":"https:\/\/staging-wp.xometry.asia\/en\/wp-json\/wp\/v2\/posts\/74017\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/staging-wp.xometry.asia\/en\/wp-json\/wp\/v2\/media\/73853"}],"wp:attachment":[{"href":"https:\/\/staging-wp.xometry.asia\/en\/wp-json\/wp\/v2\/media?parent=74017"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/staging-wp.xometry.asia\/en\/wp-json\/wp\/v2\/categories?post=74017"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/staging-wp.xometry.asia\/en\/wp-json\/wp\/v2\/tags?post=74017"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}