It is said that Einstein began his inquiry into relativity as a teenager working in his father’s electric motor shop because the Maxwell and Gauss equations did not adequately explain the difference between a motor and a generator. Whew! If it took Einstein to explain the difference, where does that put the rest of us?
Magnetism remains a poorly understood phenomenon at best, in spite of the fact that every electric motor in the world is the result of a basic understanding of electromagnetism and magnets. This would seem at odds with the fact that there are only a few ferromagnetic elements in the periodic table; Iron, Nickel, and Cobalt. The three elements are all next to each other in the middle of the periodic table.
You would think that with so few materials to work with it would be easy to characterize, but the number of alloys and complex additive materials has lead to dozens of useful materials. For those old enough to remember magnetic audio recording, the cassette and 8 track tapes of the 1960’s and 1970’s were all made using magnetic powders applied to thin mylar strips. Manufacturers came up with all manner of performance enhancements based on new alloy mixtures that improved frequency content of the playback.
Even more interesting was the creation of improved permeability magnetic alloys for the record and playback heads of tape recorders. The recording head of the tape recorder was critical to the performance of the machine and the use of exotic alloys in the magnetic recording head became very popular feature of quality equipment.
Strangely, the advancement of alloys used in magnetic recording systems did not translate into improved performance in electric motor technology. In later years motor performance did become influenced by the use of silicon steels in the stator, or inductor side of the motor. This was mostly a result of the higher efficiency that stainless steel alloys produce when used in the stator of an electric motor. Some manufacturers began producing motors using the higher grade steel, but legislation created the demand for more widespread application of high efficiency machines.
The semiconductor industry began developing unusual thin film magnetic materials for the surface of the disk in hard disk and the now obsolete floppy disk drive. These alloys have been around for some time, but are largely based on the known materials from the audio tape era.
Evan the humble kitchen magnet started out from the basic building block of powdered ceramic magnets with some vinyl binder and glue.
Somehow, despite the widespread demand for magnetic materials, and the incredible number of variations available, the impact on the electric motor has been very limited. Perhaps the high cost of exotics has been a limitation.
It is a challenge we need to address.