Spinning an aluminum can in a motor stator - GIF

Spinning an aluminum can in a motor stator.

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Previously:

https://www.homemadetools.net/forum/...670#post136574
https://www.homemadetools.net/forum/...657#post174472
https://www.homemadetools.net/forum/...359#post227971
https://www.homemadetools.net/forum/...302#post200104
https://www.homemadetools.net/forum/...913#post190957

What's the purpose of the tapping?

And Al has very little magnetic attraction?

hoping the tapping was because some of the pole keepers may have been a little loose

Quote:

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Originally Posted by Bony

And Al has very little magnetic attraction?

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Aluminium isn't magnetic, but the induced currents in the aluminium (because it is a conductor) create a magnetic feild which interacts with the rotating feild in the stator. Copper isn't magnetic either, yet moves in a magnetic feild when it has a current in it for the same reason (think coils in a loudspeaker). The forces exerted on a conductor (with current present) in a magnetic feild are defined by Lenz's law. Lenz's law has no consideration regardign if the conductor is a magnetic material or not since it is the current which is interacting, not the material containing the current.
The iron/steel in a commercial motor is predominantly there to help shape and concentrate the magnetic field... it also adds some other effects like rotational inertia, etc but the principal purpose is to shape the flux field to improve magnetic coupling, and therefore improve efficiency.