So i got this idea waay back when i was in highschool as a kind of electromagnetic analogue to a biological muscle. it is basically a long stack of thin electromagnets connected in parallel. (the picture). when current is applied gaps between electromagnets shrink thus providing contraction of the whole chain.

I am pretty sure it can work. It can't offer great contraction range (up to 50% i would guess) but it has potential to provide good speed and be compact so that multiple chains can be combined to form stong and fast linear actuators. The thing is, i never heard of this type of actuator being used. so what is the catch? is there a better alternative? is there a design flaw? too much heat generated making them unpractical?


1 Answer 1


This design is definitely plausible, but there are some problems I can see.

  • The maximum length is defined by the force the magnets can lift, since the ones lowest in the stack won't push the other ones up after some amount of them.
  • The magnets will want to get as far from the force as possible, so they will most definitely not go straight up. This calls for a use of something like a flexible tube. This may mean the design won't be as space-efficient as it seems (if it is even possible).
  • The stack won't keep it's shape if the magnets are not energized all the time, so the current consumption may be bigger than readily-available parts.

It is an interesting concept, but I can't see using it to lift any significant load to a reasonable distance.

  • $\begingroup$ I didn't consider added weight of all the magnets down the chain. that is obviously an issue. I neglected to mention that initial idea included some sort of compressible spongy material between magnets so the chain stays together. $\endgroup$ Aug 28, 2013 at 14:55

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.