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chalker wrote: 2. Bar magnets. Since one end is N and the other is S, if you get a long enough bar magnet you can just use them like railroad ties. Obviously 'flipping them over' won't do anything since they are standard bar magnets. If you want to have the same polarity, you need to get shorted bar magnets and put 2 per row (but technically then you actually have 4 magnetic rails (N-S-S-N).

While it is true that the "standard" bar magnet does have a north and south end, the magnets (at least the ones from Kelvin) are magnetized through the face of the magnet. To demonstrate this, if you take two of the rectangular magnets sold by Kelvin and connect them so that they form the longest possible magnet (i.e. short sides touching) and then merely rotate one of the magnets about the axis going down the length of the two of them, it will suddenly be repelled. This is so even though no end-to-end flipping has been performed. This means that laying two rows of magnets with all of the North sides facing up is easy.

Rule 3, i. prohibits integrated circuits.

Is that just ICs or did they mean all semi-conductors?

erikb wrote:Rule 3, i. prohibits integrated circuits.

Is that just ICs or did they mean all semi-conductors?

Purely personal opinion- usual caveats, "only official place for clarifications is..."

1) IC mention is in conjunction with brushless motors (which require fairly complex ICs to work)
2) there is no language addressing/mentioning/allowing/prohibiting other electrical/electronic components
3) definition of IC is multiple, integrated, circuits
4) a single semi-conductor is not an IC
5) multiple semi-conductors, unless 'integrated' onto some sort of....substrate do not constitute an "IC."

Balsa Man wrote:

erikb wrote:Rule 3, i. prohibits integrated circuits.

Is that just ICs or did they mean all semi-conductors?

Purely personal opinion- usual caveats, "only official place for clarifications is..."

1) IC mention is in conjunction with brushless motors (which require fairly complex ICs to work)
2) there is no language addressing/mentioning/allowing/prohibiting other electrical/electronic components
3) definition of IC is multiple, integrated, circuits
4) a single semi-conductor is not an IC
5) multiple semi-conductors, unless 'integrated' onto some sort of....substrate do not constitute an "IC."

I agree with balsa's interpretation (that's all it is though, a interpretation). A event supervisor could rule else-wise without the necessary clarification from soinc.

Has anyone been able to get their maglev to levitate without touching the side rails AT ALL? I have exhausted a great deal of effort to solve this problem and I have made very little progress towards a perfectly levitated train.

sodiumgood wrote:Has anyone been able to get their maglev to levitate without touching the side rails AT ALL? I have exhausted a great deal of effort to solve this problem and I have made very little progress towards a perfectly levitated train.

As mentioned before on this thread, Earnshaw's theorem appears to prohibit this.

sodiumgood wrote:Has anyone been able to get their maglev to levitate without touching the side rails AT ALL? I have exhausted a great deal of effort to solve this problem and I have made very little progress towards a perfectly levitated train.

Unless you have magnets on the sides of the track and the car, touching the side rails is pretty much unavoidable. Assuming you're not trying side magnets, as long as your car's width is just under the track width, touching the sides won't matter much and it'll go down the track just fine. You could then also try lining the sides with low friction material or bearings to minimize the effects.

Are magnet strips ideal for this year's parameter? I tried to place a 1+ kg cart on the track I bought last year from Science Kit, and it's touching the bottom magnet strips already. I am planning on replacing the strips with bar magnets with holes (5 lb max pull). Do you think this will be enough for a 2 kg car?

We're having the same issue with pitsco magnet strips. One suggestion is to try doubling up on the magnets on your car, but I haven't tried it yet. I know some people were able to levitate more than 2kg without rare earth magnets last year so there must be a way.

iwonder wrote:We're having the same issue with pitsco magnet strips. One suggestion is to try doubling up on the magnets on your car, but I haven't tried it yet. I know some people were able to levitate more than 2kg without rare earth magnets last year so there must be a way.

In my experience, those magnet strips won't cut it for anything over a kilogram. Doubling up could work, but I'd recommend moving to ceramic block magnets, and by doing some searching it can actually be pretty affordable.