5 ms·
It's mostly Coulomb's law; electrostatic force is proportional to the involved charges divided by their separation. You don't have that problem in electromagnet
by blattimwind 7y ago
It's mostly Coulomb's law; electrostatic force is proportional to the involved charges divided by their separation. You don't have that problem in electromagnetic motors because strong magnetic fields don't break down the rotor/stator air gap. You might turn the air gap into a dielectric oil gap, but now you have fluid friction losses which again limit how narrow that gap can be.
You'll note that this is a recurring pattern with electromagnetic vs. electrostatic implementations of roughly the same idea.
- mrfusion 7y agoGood explanation. So it makes me wonder if we could improve on the capacitor if we could find its magnetic counterpart. Does that even make sense?
- hwillis 7y agolike... an inductor? Inductors and capacitors are opposite in behavior, but a series capacitor can be replaced with a parallel inductor and vice versa. In that sense they are counterparts. It is not possible to make an inductor out of purely passive capacitive components, or vice versa. In fact the Gyrator[1] is a transistor circuit that exists specifically to act like an large inductor using capacitors, which are cheaper to build at large values. The function of a Gyrator inherently requires active power input; it isn't possible to passively convert the phase lag of a magnetic circuit into the phase lead of a capacitive circuit. [1]: https://en.wikipedia.org/wiki/Gyrator https://en.wikipedia.org/wiki/Gyrator