Minimalist motor

Someone asked me how a motor works so I put together this absolute minimalist DC motor as a demonstration.

Attachment 50187

Two stanchions made of bent paperclips support a coil of magnet wire above a Harbor Freight magnet. The coil is free to spin in the supports. A small power supply supplies a couple of volts to make it work. As the video shows, it hums right along.

https://www.youtube.com/watch?v=fOnfm5MG884

Now, a puzzle for you to solve. This configuration of motor requires a commutator to work yet none is visible. How is commutation accomplished?

I'm guessing that you removed some insulation at certain degrees from each end of the coil wire that rides in the powered supports, or maybe all of the insulation from one end and some strips from the other end.

It could be a totally wrong observation. Either way or neither way, that's a neat little demonstration.

Quote:

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Originally Posted by ductape

I'm guessing that you removed some insulation at certain degrees from each end of the coil wire that rides in the powered supports, or maybe all of the insulation from one end and some strips from the other end.

It could be a totally wrong observation. Either way or neither way, that's a neat little demonstration.

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Absolutely correct. Congratulations.

One of the "axle" wires has all its insulation removed. On the other axle wire the insulation is scraped off on only one side. Thus, as the coil spins, it receives pulses of current when the bare side of the wire comes in contact with the supports.