When a really powerful permanent magnet is put next to an electromagnet, the EM loses power. Why?
Ok, check this out: An electromagnet is simply many coils of wire wrapped around a material that is ferromagnetic (iron works nicely). When you run a current through the wire you get a magnetic field inside the coil, that magnetic field goes through the Ferromagnet. Now the ferromagnet has many randomly distributed magnetic domains, which means their magnetization cancels out in a normal situation. However, those domains tend to align when in the presence of a magnetic field (like the one being provided by your coils!). When the magnetic domains begin to align, they create a net magnetic field that is much more powerful than what you’d be able to get with just a coil. When the powerful permanent magnet comes into play, you get ANOTHER field that acts on the ferromagnet, causing its domains to want to shift in the direction of the new field. Depending on the alignment of your EM and Permanent magnet, you could either cause it to reinforce the EM or cause the EM to become weaker.
