The railgun revisited

[Low-Q]

Sure the magnet is the dominant magnetic field. From 5A and single winding "coil" it does not produce much magtism. So little it cannot make the rod roll, but the tiny magnetic field is "grabbed" by the stronger field from the magnet. That is demonstrated when you swap polarity on the powersupply.

How are you using coils instead for this experiment?

Vidar

[broli]

See below image for the next experiment. The reason why I performed the wide rail experiment was to lead up to this experiment and more.

So the next question is will the coil move or not? Again considering the magnet array is long enough.

[broli]

Recently I have been playing around with this concept again and I believe I have discovered something interesting that I have not seen before here or anywhere.

Most are familliar with the "Laplace Rail" experiment, for the unfamiliar please watch this:

https://www.youtube.com/watch?v=A5Z-FHfs7tg

This can also be used to show an induced voltage when the rail is moved by hand:

https://www.youtube.com/watch?v=2TB2mnfR4Qo

This so far is all well understood behavior. However an interesting question arises now; What happens if you remove all magnets below the rails and stick a single magnet to the moving rod, so the magnet now moves with the rod:

A) No voltage is induced because the magnet is moving with the conductor
B) A voltage is induced just like when the magnets were stationary below the rails
C) A voltage is induced but with opposite sign

I did this experiment and know the results but it's interesting to see what you guys might guess because it gets much more interesting then that.

[broli]

Well the answer seems to be a mix of A and B. In the following experiment you see the reversibility of the induced voltage:

https://www.youtube.com/watch?v=yny1mkUpUks

This seems to indicate the a voltage is induced even if the magnet and conductor are moving together.