Garden Railway Forum

Does any one have any information where to buy non polarised magnets from? I can't seem to find any, not even from China

I'm happy to be corrected, but I don't think that such a thing exists? What makes you think they do?

I do vaguely thnk I've read something about toroidal electromagnets not having poles - is that how the subatomic accelerators work? ( probably wrong its waaaay outside my brain power!).

I know nothing on the subject but, if they are for coupling wagons etc. Trevor Thompson has done work on this and developed his own 3D printed system.

I came across non polarised magnetic couplings on eBay and it looks to me as if they comprise two tiny round magnets mounted side by side.
https://www.ebay.co.uk/itm/234518129714
Presumably, one magnet has its N end exposed and the other has its S end exposed. I worked out that, provided the couplings are mounted on an item of stock correctly, they would always couple up whichever way the vehicle was facing.

Rik

That makes sense Rik, in that it is the coupling that is non polarised, not the magnet, which is what Steve asked about.

However, uncoupling could be a bit of a 'mare if the magnets are strong enough to hold the length of a train.

I don't think the idea of a non polarised magnet is what you think it is.

There may be some clever definition of "non polarised" in the realms of advanced particle physics - but that is beyond my knowledge. However vague memory suggests that it might involve rotating magnetic fields.

Back to couplings. If a magnet isn't polarised I would have thought it was not magnetised. All magnets which are magnetised must have poles. It is part of how they work. A magnet generates a magnetic field, which is conventionally visualised as lines emanating from one pole swinging around the magnet and entering at the other pole. Hence a N and a S pole, where the fields converge on the ends of the magnets. Then there is all that stuff about like poles repelling etc.

The coupling in the picture does have 2 magnets in it - visible - in the photos. I am sure that it works as you suggest whichever end of the vehicle it is attached to. The magnets in the photo are smaller than the ones I have found satisfactory - but I can't comment beyond that. However those are not non polarised magnets. The coupling may be "non polarised" in that it is used on both ends of a coach etc. The magnets are not non polarised.

As Peter said I have been using magnetic couplings for the last season. I have converted almost everything to magnetic couplings. I have successfully hauled long trains up my 1:60 gradients held together only by magnets. Including my 10 coach quarryman's train. Uncoupling is no problem. You can just pull the wagons apart - or preferably slide the couplings sideways and they part easily. I think I have already shared it all as a topic on its own - and the files to print the couplings. Of course there is the issue of them only coupling when the stock is the right way around. That isn't an issue in practice. If they are placed on the track the right way around the problem doesn't occur. I have to admit that on an end to end line, like mine, (without turntables) then it will never be an issue. Locomotives always face up hill etc.

If further comments and photos are required perhaps we can go to my thread on magnetic couplings.

Trevor

ge_rik wrote: ↑Wed Dec 07, 2022 8:55 am I came across non polarised magnetic couplings on eBay and it looks to me as if they comprise two tiny round magnets mounted side by side.
https://www.ebay.co.uk/itm/234518129714

Those are from our new member, Porterhouse Models, I think? Or very similar.

Cheers,

Andrew

I experimented with magnetic couplings using some small jewellery magnets. I needed to ensure wagons were the correct way round on the track so the magnets were N/S N/S N/S the length of the train. The magnets I used were a bit small for the job and too much tension would cause the wagons to separate. Another problem was when fitted to locos (or metal bodied wagons such as Mamod ) the magnets became more interested in the buffer beam than the magnet on the adjacent wagon. The magnetic couplings shown above presumably overcome these shortcomings.

Andrew wrote: ↑Wed Dec 07, 2022 11:42 am

ge_rik wrote: ↑Wed Dec 07, 2022 8:55 am I came across non polarised magnetic couplings on eBay and it looks to me as if they comprise two tiny round magnets mounted side by side.
https://www.ebay.co.uk/itm/234518129714

Those are from our new member, Porterhouse Models, I think? Or very similar.

Cheers,

Andrew

Yes they are available from us.

As long as the couplings are mounted the same way up you can couple to either end of the vehicle as the magnets are all mounted in the buffer housing the same way.

There is a bit more information on our page about them.

https://www.porterhousemodels.co.uk/sto ... -couplings

Best wishes

Porterhouse Models

Have you devised a remote uncoupler for these?

Phil.P

Phil.P wrote: ↑Thu Dec 08, 2022 9:29 pm Have you devised a remote uncoupler for these?

Phil.P

I wondered about that. What would happen if a third magnet was introduced at the interface between the couplings? Would it increase the magnetic effect or cancel it out?

Rik

I have an idea or two..

I will need to get a couple of pairs of magnetic couplings..

Phil.P