I am interface designer that occasionally steps out and does some product/concept design. The last one I'm working on is something that would require me to make a matrix of little electromagnets, and i am just starting to inform my self about all that.
For the project I'm playing with right now, I used 1x1x1cm neodymium magnet for experimenting, and it did the job just perfectly. I tried bigger, I tried smaller, but this one is perfect.
The problem is that i need an electromagnet to do the same thing in future. (probably lots of them)
The question is, how large does an electromagnet needs to be in volume to have the same/similar power as neodymium magnet sized 1x1x1cm.
Or even better question, how small can it be, because I really need it small but powerful.
The point of the question is just for me to hear someone experienced on the subject with some theoretical answer (Because i assume it will be enough for this stage of exploration). The real work will be done in collaboration with some professional guy just like you that I will look for if i decide to dive into all this.
Now I am aware of the fact that there are probably different ways you can measure one magnets strength, and that not all neodymium magnets are the same, so it can't be treated as a constant, but I would just like to know in general, is it like 2ccm electromagnet or is it like 20ccm electromagnet.
Best Answer
On the one hand, @sai's reasoning seems sound, on the other hand, we should not forget that an electromagnet can have a ferromagnetic core. I cannot offer any specific data right now, but I would suspect that an electromagnet with a suitable core might have comparable strength to that of a permanent magnet. The core can be magnetically soft, so it can have little average permanent magnetization when the electromagnet is switched off.
Using an electromagnet, you need extra power and/or cooling, but you also have extra control (you can vary or switch on/off the magnetic field at will).