Back in the old days, before home computers, there were certain things that technically minded boys just had to have done, and one of those was to build a working electric motor from scratch. I built this one when I unexpectedly had time off school because of a fire in the auto shop there.
The main shaft is a nail. The armature is a stack of metal sheets salvaged from a transformer. The commutator is a bit of wooden dowel with contacts formed out of aluminum (not, in retrospect, a good commutator material). The brushes are 14 gauge copper wire. The stator is just a scrap of sheet metal bent into a "U" shape.
A primitive 2-pole motor like this has no practical use whatsoever. It won't start if the rotor happens to be horizontal. It barely develops enough power to stay running, and it would wear out quickly if it was left running due to the primitive commutator and nonexistent bearing technology.
But it works. With a suitable power supply (e.g. a car battery) it spins up to maybe 2000-3000rpm. And that's all the justification needed for building it, really. I made my own working electric motor!
I was 15 years old at the time. Nowadays I guess it would be "I made my own web blog system" or something like that.
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